[PATCH 0/5] submodule config lookup API

[PATCH 0/5] submodule config lookup API

[Heiko Voigt]

I have been holding back this series during the RC phase but now I think
it is ready for another round. The most important changes:

  * The API is using a singleton now. No need to pass in the cache
    object anymore.

  * Local configuration can be looked up by passing in the null_sha1

  * We use the API for existing lookup of submodule values

One open question:

  * Since behind the scenes there is a global cache filled with the
    values: Do we need to free it explicitely? Or is it ok to let it be
    dealt with on exit?

The last iteration was here:

http://article.gmane.org/gmane.comp.version-control.git/243818

Heiko Voigt (5):
  hashmap: add enum for hashmap free_entries option
  implement submodule config cache for lookup of submodule names
  extract functions for submodule config set and lookup
  use new config API for worktree configurations of submodules
  do not die on error of parsing fetchrecursesubmodules option

 .gitignore                                       |   1 +
 Documentation/technical/api-hashmap.txt          |   2 +-
 Documentation/technical/api-submodule-config.txt |  63 ++++
 Makefile                                         |   2 +
 builtin/checkout.c                               |   1 +
 builtin/fetch.c                                  |   1 +
 diff.c                                           |   1 +
 diffcore-rename.c                                |   2 +-
 hashmap.c                                        |   2 +-
 hashmap.h                                        |   8 +-
 name-hash.c                                      |   4 +-
 submodule-config.c                               | 435 +++++++++++++++++++++++
 submodule-config.h                               |  29 ++
 submodule.c                                      | 122 ++-----
 submodule.h                                      |   4 +-
 t/t7410-submodule-config.sh                      | 141 ++++++++
 test-hashmap.c                                   |   6 +-
 test-submodule-config.c                          |  74 ++++
 18 files changed, 791 insertions(+), 107 deletions(-)
 create mode 100644 Documentation/technical/api-submodule-config.txt
 create mode 100644 submodule-config.c
 create mode 100644 submodule-config.h
 create mode 100755 t/t7410-submodule-config.sh
 create mode 100644 test-submodule-config.c

-- 
2.0.0

[PATCH 1/5] hashmap: add enum for hashmap free_entries option

[Heiko Voigt]

This allows a reader to immediately know which options can be used and
what this parameter is about.

Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
---
 Documentation/technical/api-hashmap.txt | 2 +-
 diffcore-rename.c                       | 2 +-
 hashmap.c                               | 2 +-
 hashmap.h                               | 8 +++++++-
 name-hash.c                             | 4 ++--
 test-hashmap.c                          | 6 +++---
 6 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/Documentation/technical/api-hashmap.txt b/Documentation/technical/api-hashmap.txt
index b977ae8..b04bb40 100644
--- a/Documentation/technical/api-hashmap.txt
+++ b/Documentation/technical/api-hashmap.txt
@@ -187,7 +187,7 @@ void long2double_init(void)
 
 void long2double_free(void)
 {
-	hashmap_free(&map, 1);
+	hashmap_free(&map, HASHMAP_FREE_ENTRIES);
 }
 
 static struct long2double *find_entry(long key)
diff --git a/diffcore-rename.c b/diffcore-rename.c
index 749a35d..f30239a 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -335,7 +335,7 @@ static int find_exact_renames(struct diff_options *options)
 		renames += find_identical_files(&file_table, i, options);
 
 	/* Free the hash data structure and entries */
-	hashmap_free(&file_table, 1);
+	hashmap_free(&file_table, HASHMAP_FREE_ENTRIES);
 
 	return renames;
 }
diff --git a/hashmap.c b/hashmap.c
index d1b8056..9a3555a 100644
--- a/hashmap.c
+++ b/hashmap.c
@@ -135,7 +135,7 @@ void hashmap_init(struct hashmap *map, hashmap_cmp_fn equals_function,
 	alloc_table(map, size);
 }
 
-void hashmap_free(struct hashmap *map, int free_entries)
+void hashmap_free(struct hashmap *map, enum hashmap_free_options free_entries)
 {
 	if (!map || !map->table)
 		return;
diff --git a/hashmap.h b/hashmap.h
index a816ad4..6c558df 100644
--- a/hashmap.h
+++ b/hashmap.h
@@ -1,6 +1,11 @@
 #ifndef HASHMAP_H
 #define HASHMAP_H
 
+enum hashmap_free_options {
+	HASHMAP_NO_FREE_ENTRIES = 0,
+	HASHMAP_FREE_ENTRIES = 1,
+};
+
 /*
  * Generic implementation of hash-based key-value mappings.
  * See Documentation/technical/api-hashmap.txt.
@@ -39,7 +44,8 @@ struct hashmap_iter {
 
 extern void hashmap_init(struct hashmap *map, hashmap_cmp_fn equals_function,
 		size_t initial_size);
-extern void hashmap_free(struct hashmap *map, int free_entries);
+extern void hashmap_free(struct hashmap *map,
+			 enum hashmap_free_options free_entries);
 
 /* hashmap_entry functions */
 
diff --git a/name-hash.c b/name-hash.c
index 97444d0..be7c4ae 100644
--- a/name-hash.c
+++ b/name-hash.c
@@ -233,6 +233,6 @@ void free_name_hash(struct index_state *istate)
 		return;
 	istate->name_hash_initialized = 0;
 
-	hashmap_free(&istate->name_hash, 0);
-	hashmap_free(&istate->dir_hash, 1);
+	hashmap_free(&istate->name_hash, HASHMAP_NO_FREE_ENTRIES);
+	hashmap_free(&istate->dir_hash, HASHMAP_FREE_ENTRIES);
 }
diff --git a/test-hashmap.c b/test-hashmap.c
index f5183fb..ac8d6a2 100644
--- a/test-hashmap.c
+++ b/test-hashmap.c
@@ -100,7 +100,7 @@ static void perf_hashmap(unsigned int method, unsigned int rounds)
 				hashmap_add(&map, entries[i]);
 			}
 
-			hashmap_free(&map, 0);
+			hashmap_free(&map, HASHMAP_NO_FREE_ENTRIES);
 		}
 	} else {
 		/* test map lookups */
@@ -121,7 +121,7 @@ static void perf_hashmap(unsigned int method, unsigned int rounds)
 			}
 		}
 
-		hashmap_free(&map, 0);
+		hashmap_free(&map, HASHMAP_NO_FREE_ENTRIES);
 	}
 }
 
@@ -250,6 +250,6 @@ int main(int argc, char *argv[])
 		}
 	}
 
-	hashmap_free(&map, 1);
+	hashmap_free(&map, HASHMAP_FREE_ENTRIES);
 	return 0;
 }
-- 
2.0.0

[PATCH 2/5] implement submodule config cache for lookup of submodule names

[Heiko Voigt]

This submodule configuration cache allows us to lazily read .gitmodules
configurations by commit into a runtime cache which can then be used to
easily lookup values from it. Currently only the values for path or name
are stored but it can be extended for any value needed.

It is expected that .gitmodules files do not change often between
commits. Thats why we lookup the .gitmodules sha1 from a commit and then
either lookup an already parsed configuration or parse and cache an
unknown one for each sha1. The cache is lazily build on demand for each
requested commit.

This cache can be used for all purposes which need knowledge about
submodule configurations. Example use cases are:

 * Recursive submodule checkout needs lookup a submodule name from its
   path when a submodule first appears. This needs be done before this
   configuration exists in the worktree.

 * The implementation of submodule support for 'git archive' needs to
   lookup the submodule name to generate the archive when given a
   revision that is not checked out.

 * 'git fetch' when given the --recurse-submodules=on-demand option (or
   configuration) needs to lookup submodule names by path from the
   database rather than reading from the worktree. For new submodule it
   needs to lookup the name from its path to allow cloning new
   submodules into the .git folder so they can be checked out without
   any network interaction when the user does a checkout of that
   revision.

Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
---
 .gitignore                                       |   1 +
 Documentation/technical/api-submodule-config.txt |  46 +++
 Makefile                                         |   2 +
 submodule-config.c                               | 396 +++++++++++++++++++++++
 submodule-config.h                               |  27 ++
 submodule.c                                      |   1 +
 submodule.h                                      |   1 +
 t/t7410-submodule-config.sh                      |  73 +++++
 test-submodule-config.c                          |  64 ++++
 9 files changed, 611 insertions(+)
 create mode 100644 Documentation/technical/api-submodule-config.txt
 create mode 100644 submodule-config.c
 create mode 100644 submodule-config.h
 create mode 100755 t/t7410-submodule-config.sh
 create mode 100644 test-submodule-config.c

diff --git a/.gitignore b/.gitignore
index dc600f9..9e3352a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -198,6 +198,7 @@
 /test-sha1
 /test-sigchain
 /test-string-list
+/test-submodule-config
 /test-subprocess
 /test-svn-fe
 /test-urlmatch-normalization
diff --git a/Documentation/technical/api-submodule-config.txt b/Documentation/technical/api-submodule-config.txt
new file mode 100644
index 0000000..2ff4907
--- /dev/null
+++ b/Documentation/technical/api-submodule-config.txt
@@ -0,0 +1,46 @@
+submodule config cache API
+==========================
+
+The submodule config cache API allows to read submodule
+configurations/information from specified revisions. Internally
+information is lazily read into a cache that is used to avoid
+unnecessary parsing of the same .gitmodule files. Lookups can be done by
+submodule path or name.
+
+Usage
+-----
+
+The caller can look up information about submodules by using the
+`submodule_from_path()` or `submodule_from_name()` functions. They return
+a `struct submodule` which contains the values. The API automatically
+initializes and allocates the needed infrastructure on-demand.
+
+If the internal cache might grow too big or when the caller is done with
+the API, all internally cached values can be freed with submodule_free().
+
+Data Structures
+---------------
+
+`struct submodule`::
+
+	This structure is used to return the information about one
+	submodule for a certain revision. It is returned by the lookup
+	functions.
+
+Functions
+---------
+
+`void submodule_free()`::
+
+	Use these to free the internally cached values.
+
+`const struct submodule *submodule_from_path(const unsigned char *commit_sha1, const char *path)`::
+
+	Lookup values for one submodule by its commit_sha1 and path or
+	name.
+
+`const struct submodule *submodule_from_name(const unsigned char *commit_sha1, const char *name)`::
+
+	The same as above but lookup by name.
+
+For an example usage see test-submodule-config.c.
diff --git a/Makefile b/Makefile
index 08fc9ca..0c96e1f 100644
--- a/Makefile
+++ b/Makefile
@@ -570,6 +570,7 @@ TEST_PROGRAMS_NEED_X += test-scrap-cache-tree
 TEST_PROGRAMS_NEED_X += test-sha1
 TEST_PROGRAMS_NEED_X += test-sigchain
 TEST_PROGRAMS_NEED_X += test-string-list
+TEST_PROGRAMS_NEED_X += test-submodule-config
 TEST_PROGRAMS_NEED_X += test-subprocess
 TEST_PROGRAMS_NEED_X += test-svn-fe
 TEST_PROGRAMS_NEED_X += test-urlmatch-normalization
@@ -878,6 +879,7 @@ LIB_OBJS += strbuf.o
 LIB_OBJS += streaming.o
 LIB_OBJS += string-list.o
 LIB_OBJS += submodule.o
+LIB_OBJS += submodule-config.o
 LIB_OBJS += symlinks.o
 LIB_OBJS += tag.o
 LIB_OBJS += trace.o
diff --git a/submodule-config.c b/submodule-config.c
new file mode 100644
index 0000000..e7ca2b0
--- /dev/null
+++ b/submodule-config.c
@@ -0,0 +1,396 @@
+#include "cache.h"
+#include "submodule-config.h"
+#include "submodule.h"
+#include "strbuf.h"
+
+/*
+ * submodule cache lookup structure
+ * There is one shared set of 'struct submodule' entries which can be
+ * looked up by their sha1 blob id of the .gitmodule file and either
+ * using path or name as key.
+ * for_path stores submodule entries with path as key
+ * for_name stores submodule entries with name as key
+ */
+struct submodule_cache {
+	struct hashmap for_path;
+	struct hashmap for_name;
+};
+
+/*
+ * thin wrapper struct needed to insert 'struct submodule' entries to
+ * the hashmap
+ */
+struct submodule_entry {
+	struct hashmap_entry ent;
+	struct submodule *config;
+};
+
+static struct submodule_cache cache;
+static int is_cache_init = 0;
+
+static int config_path_cmp(const struct submodule_entry *a,
+			   const struct submodule_entry *b,
+			   const void *unused)
+{
+	return strcmp(a->config->path, b->config->path) ||
+	       hashcmp(a->config->gitmodules_sha1, b->config->gitmodules_sha1);
+}
+
+static int config_name_cmp(const struct submodule_entry *a,
+			   const struct submodule_entry *b,
+			   const void *unused)
+{
+	return strcmp(a->config->name, b->config->name) ||
+	       hashcmp(a->config->gitmodules_sha1, b->config->gitmodules_sha1);
+}
+
+static void cache_init(struct submodule_cache *cache)
+{
+	hashmap_init(&cache->for_path, (hashmap_cmp_fn) config_path_cmp, 0);
+	hashmap_init(&cache->for_name, (hashmap_cmp_fn) config_name_cmp, 0);
+}
+
+static void free_one_config(struct submodule_entry *entry)
+{
+	free((void *) entry->config->path);
+	free((void *) entry->config->name);
+	free(entry->config);
+}
+
+static void cache_free(struct submodule_cache *cache)
+{
+	struct hashmap_iter iter;
+	struct submodule_entry *entry;
+
+	/*
+	 * We iterate over the name hash here to be symmetric with the
+	 * allocation of struct submodule entries. Each is allocated by
+	 * their .gitmodule blob sha1 and submodule name.
+	 */
+	hashmap_iter_init(&cache->for_name, &iter);
+	while ((entry = hashmap_iter_next(&iter)))
+		free_one_config(entry);
+
+	hashmap_free(&cache->for_path, HASHMAP_FREE_ENTRIES);
+	hashmap_free(&cache->for_name, HASHMAP_FREE_ENTRIES);
+}
+
+static unsigned int hash_sha1_string(const unsigned char *sha1,
+				     const char *string)
+{
+	return memhash(sha1, 20) + strhash(string);
+}
+
+static void cache_put_path(struct submodule_cache *cache,
+			   struct submodule *submodule)
+{
+	unsigned int hash = hash_sha1_string(submodule->gitmodules_sha1,
+					     submodule->path);
+	struct submodule_entry *e = xmalloc(sizeof(*e));
+	hashmap_entry_init(e, hash);
+	e->config = submodule;
+	hashmap_put(&cache->for_path, e);
+}
+
+static void cache_remove_path(struct submodule_cache *cache,
+			      struct submodule *submodule)
+{
+	unsigned int hash = hash_sha1_string(submodule->gitmodules_sha1,
+					     submodule->path);
+	struct submodule_entry e;
+	struct submodule_entry *removed;
+	hashmap_entry_init(&e, hash);
+	e.config = submodule;
+	removed = hashmap_remove(&cache->for_path, &e, NULL);
+	free(removed);
+}
+
+static void cache_add(struct submodule_cache *cache,
+		      struct submodule *submodule)
+{
+	unsigned int hash = hash_sha1_string(submodule->gitmodules_sha1,
+					     submodule->name);
+	struct submodule_entry *e = xmalloc(sizeof(*e));
+	hashmap_entry_init(e, hash);
+	e->config = submodule;
+	hashmap_add(&cache->for_name, e);
+}
+
+static const struct submodule *cache_lookup_path(struct submodule_cache *cache,
+		const unsigned char *gitmodules_sha1, const char *path)
+{
+	struct submodule_entry *entry;
+	unsigned int hash = hash_sha1_string(gitmodules_sha1, path);
+	struct submodule_entry key;
+	struct submodule key_config;
+
+	hashcpy(key_config.gitmodules_sha1, gitmodules_sha1);
+	key_config.path = path;
+
+	hashmap_entry_init(&key, hash);
+	key.config = &key_config;
+
+	entry = hashmap_get(&cache->for_path, &key, NULL);
+	if (entry)
+		return entry->config;
+	return NULL;
+}
+
+static struct submodule *cache_lookup_name(struct submodule_cache *cache,
+		const unsigned char *gitmodules_sha1, const char *name)
+{
+	struct submodule_entry *entry;
+	unsigned int hash = hash_sha1_string(gitmodules_sha1, name);
+	struct submodule_entry key;
+	struct submodule key_config;
+
+	hashcpy(key_config.gitmodules_sha1, gitmodules_sha1);
+	key_config.name = name;
+
+	hashmap_entry_init(&key, hash);
+	key.config = &key_config;
+
+	entry = hashmap_get(&cache->for_name, &key, NULL);
+	if (entry)
+		return entry->config;
+	return NULL;
+}
+
+static int name_and_item_from_var(const char *var, struct strbuf *name,
+				  struct strbuf *item)
+{
+	const char *subsection, *key;
+	int subsection_len, parse;
+	parse = parse_config_key(var, "submodule", &subsection,
+			&subsection_len, &key);
+	if (parse < 0 || !subsection)
+		return 0;
+
+	strbuf_add(name, subsection, subsection_len);
+	strbuf_addstr(item, key);
+
+	return 1;
+}
+
+static struct submodule *lookup_or_create_by_name(struct submodule_cache *cache,
+		const unsigned char *gitmodules_sha1, const char *name)
+{
+	struct submodule *submodule;
+	struct strbuf name_buf = STRBUF_INIT;
+
+	submodule = cache_lookup_name(cache, gitmodules_sha1, name);
+	if (submodule)
+		return submodule;
+
+	submodule = xmalloc(sizeof(*submodule));
+
+	strbuf_addstr(&name_buf, name);
+	submodule->name = strbuf_detach(&name_buf, NULL);
+
+	submodule->path = NULL;
+	submodule->url = NULL;
+	submodule->fetch_recurse = RECURSE_SUBMODULES_NONE;
+	submodule->ignore = NULL;
+
+	hashcpy(submodule->gitmodules_sha1, gitmodules_sha1);
+
+	cache_add(cache, submodule);
+
+	return submodule;
+}
+
+static void warn_multiple_config(const unsigned char *commit_sha1,
+				 const char *name, const char *option)
+{
+	const char *commit_string = "WORKTREE";
+	if (commit_sha1)
+		commit_string = sha1_to_hex(commit_sha1);
+	warning("%s:.gitmodules, multiple configurations found for "
+			"submodule.%s.%s. Skipping second one!",
+			commit_string, name, option);
+}
+
+struct parse_config_parameter {
+	struct submodule_cache *cache;
+	const unsigned char *commit_sha1;
+	const unsigned char *gitmodules_sha1;
+	int overwrite;
+};
+
+static int parse_config(const char *var, const char *value, void *data)
+{
+	struct parse_config_parameter *me = data;
+	struct submodule *submodule;
+	struct strbuf name = STRBUF_INIT, item = STRBUF_INIT;
+	int ret = 0;
+
+	/* this also ensures that we only parse submodule entries */
+	if (!name_and_item_from_var(var, &name, &item))
+		return 0;
+
+	submodule = lookup_or_create_by_name(me->cache, me->gitmodules_sha1,
+			name.buf);
+
+	if (!strcmp(item.buf, "path")) {
+		struct strbuf path = STRBUF_INIT;
+		if (!value) {
+			ret = config_error_nonbool(var);
+			goto release_return;
+		}
+		if (!me->overwrite && submodule->path != NULL) {
+			warn_multiple_config(me->commit_sha1, submodule->name,
+					"path");
+			goto release_return;
+		}
+
+		if (submodule->path)
+			cache_remove_path(me->cache, submodule);
+		free((void *) submodule->path);
+		strbuf_addstr(&path, value);
+		submodule->path = strbuf_detach(&path, NULL);
+		cache_put_path(me->cache, submodule);
+	} else if (!strcmp(item.buf, "fetchrecursesubmodules")) {
+		if (!me->overwrite &&
+		    submodule->fetch_recurse != RECURSE_SUBMODULES_NONE) {
+			warn_multiple_config(me->commit_sha1, submodule->name,
+					"fetchrecursesubmodules");
+			goto release_return;
+		}
+
+		submodule->fetch_recurse = parse_fetch_recurse_submodules_arg(var, value);
+	} else if (!strcmp(item.buf, "ignore")) {
+		struct strbuf ignore = STRBUF_INIT;
+		if (!me->overwrite && submodule->ignore != NULL) {
+			warn_multiple_config(me->commit_sha1, submodule->name,
+					"ignore");
+			goto release_return;
+		}
+		if (!value) {
+			ret = config_error_nonbool(var);
+			goto release_return;
+		}
+		if (strcmp(value, "untracked") && strcmp(value, "dirty") &&
+		    strcmp(value, "all") && strcmp(value, "none")) {
+			warning("Invalid parameter \"%s\" for config option "
+					"\"submodule.%s.ignore\"", value, var);
+			goto release_return;
+		}
+
+		free((void *) submodule->ignore);
+		strbuf_addstr(&ignore, value);
+		submodule->ignore = strbuf_detach(&ignore, NULL);
+	} else if (!strcmp(item.buf, "url")) {
+		struct strbuf url = STRBUF_INIT;
+		if (!value) {
+			ret = config_error_nonbool(var);
+			goto release_return;
+		}
+		if (!me->overwrite && submodule->url != NULL) {
+			warn_multiple_config(me->commit_sha1, submodule->name,
+					"url");
+			goto release_return;
+		}
+
+		free((void *) submodule->url);
+		strbuf_addstr(&url, value);
+		submodule->url = strbuf_detach(&url, NULL);
+	}
+
+release_return:
+	strbuf_release(&name);
+	strbuf_release(&item);
+
+	return ret;
+}
+
+static const struct submodule *config_from_path(struct submodule_cache *cache,
+		const unsigned char *commit_sha1, const char *path)
+{
+	struct strbuf rev = STRBUF_INIT;
+	unsigned long config_size;
+	char *config;
+	unsigned char sha1[20];
+	enum object_type type;
+	const struct submodule *submodule = NULL;
+	struct parse_config_parameter parameter;
+
+	/*
+	 * If any parameter except the cache is a NULL pointer just
+	 * return the first submodule. Can be used to check whether
+	 * there are any submodules parsed.
+	 */
+	if (!commit_sha1 || !path) {
+		struct hashmap_iter iter;
+		struct submodule_entry *entry;
+
+		hashmap_iter_init(&cache->for_name, &iter);
+		entry = hashmap_iter_next(&iter);
+		if (!entry)
+			return NULL;
+		return entry->config;
+	}
+
+	if (is_null_sha1(commit_sha1))
+		return cache_lookup_path(cache, null_sha1, path);
+
+	strbuf_addf(&rev, "%s:.gitmodules", sha1_to_hex(commit_sha1));
+	if (get_sha1(rev.buf, sha1) < 0)
+		goto free_rev;
+
+	submodule = cache_lookup_path(cache, sha1, path);
+	if (submodule)
+		goto free_rev;
+
+	config = read_sha1_file(sha1, &type, &config_size);
+	if (!config)
+		goto free_rev;
+
+	if (type != OBJ_BLOB) {
+		free(config);
+		goto free_rev;
+	}
+
+	/* fill the submodule config into the cache */
+	parameter.cache = cache;
+	parameter.commit_sha1 = commit_sha1;
+	parameter.gitmodules_sha1 = sha1;
+	parameter.overwrite = 0;
+	git_config_from_buf(parse_config, rev.buf, config, config_size,
+			&parameter);
+	free(config);
+
+	submodule = cache_lookup_path(cache, sha1, path);
+
+free_rev:
+	strbuf_release(&rev);
+	return submodule;
+}
+
+static void ensure_cache_init()
+{
+	if (is_cache_init)
+		return;
+
+	cache_init(&cache);
+	is_cache_init = 1;
+}
+
+const struct submodule *submodule_from_name(const unsigned char *commit_sha1,
+		const char *name)
+{
+	ensure_cache_init();
+	return cache_lookup_name(&cache, commit_sha1, name);
+}
+
+const struct submodule *submodule_from_path(const unsigned char *commit_sha1,
+		const char *path)
+{
+	ensure_cache_init();
+	return config_from_path(&cache, commit_sha1, path);
+}
+
+void submodule_free()
+{
+	cache_free(&cache);
+	is_cache_init = 0;
+}
diff --git a/submodule-config.h b/submodule-config.h
new file mode 100644
index 0000000..972496d
--- /dev/null
+++ b/submodule-config.h
@@ -0,0 +1,27 @@
+#ifndef SUBMODULE_CONFIG_CACHE_H
+#define SUBMODULE_CONFIG_CACHE_H
+
+#include "hashmap.h"
+#include "strbuf.h"
+
+/*
+ * Submodule entry containing the information about a certain submodule
+ * in a certain revision.
+ */
+struct submodule {
+	const char *path;
+	const char *name;
+	const char *url;
+	int fetch_recurse;
+	const char *ignore;
+	/* the sha1 blob id of the responsible .gitmodules file */
+	unsigned char gitmodules_sha1[20];
+};
+
+const struct submodule *submodule_from_name(const unsigned char *commit_sha1,
+		const char *name);
+const struct submodule *submodule_from_path(const unsigned char *commit_sha1,
+		const char *path);
+void submodule_free();
+
+#endif /* SUBMODULE_CONFIG_H */
diff --git a/submodule.c b/submodule.c
index b80ecac..85e2b12 100644
--- a/submodule.c
+++ b/submodule.c
@@ -355,6 +355,7 @@ int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg)
 	default:
 		if (!strcmp(arg, "on-demand"))
 			return RECURSE_SUBMODULES_ON_DEMAND;
+		/* TODO: remove the die for history parsing here */
 		die("bad %s argument: %s", opt, arg);
 	}
 }
diff --git a/submodule.h b/submodule.h
index 7beec48..920fef3 100644
--- a/submodule.h
+++ b/submodule.h
@@ -5,6 +5,7 @@ struct diff_options;
 struct argv_array;
 
 enum {
+	RECURSE_SUBMODULES_NONE = -2,
 	RECURSE_SUBMODULES_ON_DEMAND = -1,
 	RECURSE_SUBMODULES_OFF = 0,
 	RECURSE_SUBMODULES_DEFAULT = 1,
diff --git a/t/t7410-submodule-config.sh b/t/t7410-submodule-config.sh
new file mode 100755
index 0000000..ea453c5
--- /dev/null
+++ b/t/t7410-submodule-config.sh
@@ -0,0 +1,73 @@
+#!/bin/sh
+#
+# Copyright (c) 2014 Heiko Voigt
+#
+
+test_description='Test submodules config cache infrastructure
+
+This test verifies that parsing .gitmodules configuration directly
+from the database works.
+'
+
+TEST_NO_CREATE_REPO=1
+. ./test-lib.sh
+
+test_expect_success 'submodule config cache setup' '
+	mkdir submodule &&
+	(cd submodule &&
+		git init
+		echo a >a &&
+		git add . &&
+		git commit -ma
+	) &&
+	mkdir super &&
+	(cd super &&
+		git init &&
+		git submodule add ../submodule &&
+		git submodule add ../submodule a &&
+		git commit -m "add as submodule and as a" &&
+		git mv a b &&
+		git commit -m "move a to b"
+	)
+'
+
+cat >super/expect <<EOF
+Submodule name: 'a' for path 'a'
+Submodule name: 'a' for path 'b'
+Submodule name: 'submodule' for path 'submodule'
+Submodule name: 'submodule' for path 'submodule'
+EOF
+
+test_expect_success 'test parsing of submodule config' '
+	(cd super &&
+		test-submodule-config \
+			HEAD^ a \
+			HEAD b \
+			HEAD^ submodule \
+			HEAD submodule \
+				>actual &&
+		test_cmp expect actual
+	)
+'
+
+cat >super/expect_error <<EOF
+Submodule name: 'a' for path 'b'
+Submodule name: 'submodule' for path 'submodule'
+EOF
+
+test_expect_success 'error in one submodule config lets continue' '
+	(cd super &&
+		cp .gitmodules .gitmodules.bak &&
+		echo "	value = \"" >>.gitmodules &&
+		git add .gitmodules &&
+		mv .gitmodules.bak .gitmodules &&
+		git commit -m "add error" &&
+		test-submodule-config \
+			HEAD b \
+			HEAD submodule \
+				>actual &&
+		test_cmp expect_error actual
+	)
+'
+
+test_done
diff --git a/test-submodule-config.c b/test-submodule-config.c
new file mode 100644
index 0000000..969d957
--- /dev/null
+++ b/test-submodule-config.c
@@ -0,0 +1,64 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "cache.h"
+#include "submodule-config.h"
+
+static void die_usage(int argc, char **argv, const char *msg)
+{
+	fprintf(stderr, "%s\n", msg);
+	fprintf(stderr, "Usage: %s [<commit> <submodulepath>] ...\n", argv[0]);
+	exit(1);
+}
+
+int main(int argc, char **argv)
+{
+	char **arg = argv;
+	int my_argc = argc;
+	int output_url = 0;
+
+	arg++;
+	my_argc--;
+	while (starts_with(arg[0], "--")) {
+		if (!strcmp(arg[0], "--url"))
+			output_url = 1;
+		arg++;
+		my_argc--;
+	}
+
+	if (my_argc % 2 != 0)
+		die_usage(argc, argv, "Wrong number of arguments.");
+
+	while (*arg) {
+		unsigned char commit_sha1[20];
+		const struct submodule *submodule;
+		const char *commit;
+		const char *path;
+
+		commit = arg[0];
+		path = arg[1];
+
+		if (commit[0] == '\0')
+			hashcpy(commit_sha1, null_sha1);
+		else if (get_sha1(commit, commit_sha1) < 0)
+			die_usage(argc, argv, "Commit not found.");
+
+		submodule = submodule_from_path(commit_sha1, path);
+		if (!submodule)
+			die_usage(argc, argv, "Submodule not found.");
+
+		if (output_url)
+			printf("Submodule url: '%s' for path '%s'\n",
+					submodule->url, path);
+		else
+			printf("Submodule name: '%s' for path '%s'\n",
+					submodule->name, path);
+
+		arg += 2;
+	}
+
+	submodule_free();
+
+	return 0;
+}
-- 
2.0.0

[PATCH 3/5] extract functions for submodule config set and lookup

[Heiko Voigt]

This is one step towards using the new configuration API. We just
extract these functions to make replacing the actual code easier.

Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
---

This refactoring is included in the series to make following the series easier
(and because it was one step I did). The extracted functions will be replaced
in the next commit with the ones from the cache. I think its easier to follow
the implementation this way. In case you think its unnecessary I can squash
this commit into the next one.


 submodule.c | 142 +++++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 97 insertions(+), 45 deletions(-)

diff --git a/submodule.c b/submodule.c
index 85e2b12..86ec2e3 100644
--- a/submodule.c
+++ b/submodule.c
@@ -41,6 +41,76 @@ static int gitmodules_is_unmerged;
  */
 static int gitmodules_is_modified;
 
+static const char *get_name_for_path(const char *path)
+{
+	struct string_list_item *path_option;
+	if (path == NULL) {
+		if (config_name_for_path.nr > 0)
+			return config_name_for_path.items[0].util;
+		else
+			return NULL;
+	}
+	path_option = unsorted_string_list_lookup(&config_name_for_path, path);
+	if (!path_option)
+		return NULL;
+	return path_option->util;
+}
+
+static void set_name_for_path(const char *path, const char *name, int namelen)
+{
+	struct string_list_item *config;
+	config = unsorted_string_list_lookup(&config_name_for_path, path);
+	if (config)
+		free(config->util);
+	else
+		config = string_list_append(&config_name_for_path, xstrdup(path));
+	config->util = xmemdupz(name, namelen);
+}
+
+static const char *get_ignore_for_name(const char *name)
+{
+	struct string_list_item *ignore_option;
+	ignore_option = unsorted_string_list_lookup(&config_ignore_for_name, name);
+	if (!ignore_option)
+		return NULL;
+
+	return ignore_option->util;
+}
+
+static void set_ignore_for_name(const char *name, int namelen, const char *ignore)
+{
+	struct string_list_item *config;
+	char *name_cstr = xmemdupz(name, namelen);
+	config = unsorted_string_list_lookup(&config_ignore_for_name, name_cstr);
+	if (config) {
+		free(config->util);
+		free(name_cstr);
+	} else
+		config = string_list_append(&config_ignore_for_name, name_cstr);
+	config->util = xstrdup(ignore);
+}
+
+static int get_fetch_recurse_for_name(const char *name)
+{
+	struct string_list_item *fetch_recurse;
+	fetch_recurse = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name);
+	if (!fetch_recurse)
+		return RECURSE_SUBMODULES_NONE;
+
+	return (intptr_t) fetch_recurse->util;
+}
+
+static void set_fetch_recurse_for_name(const char *name, int namelen, int fetch_recurse)
+{
+	struct string_list_item *config;
+	char *name_cstr = xmemdupz(name, namelen);
+	config = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name_cstr);
+	if (!config)
+		config = string_list_append(&config_fetch_recurse_submodules_for_name, name_cstr);
+	else
+		free(name_cstr);
+	config->util = (void *)(intptr_t) fetch_recurse;
+}
 
 int is_staging_gitmodules_ok(void)
 {
@@ -55,7 +125,7 @@ int is_staging_gitmodules_ok(void)
 int update_path_in_gitmodules(const char *oldpath, const char *newpath)
 {
 	struct strbuf entry = STRBUF_INIT;
-	struct string_list_item *path_option;
+	const char *path;
 
 	if (!file_exists(".gitmodules")) /* Do nothing without .gitmodules */
 		return -1;
@@ -63,13 +133,13 @@ int update_path_in_gitmodules(const char *oldpath, const char *newpath)
 	if (gitmodules_is_unmerged)
 		die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
 
-	path_option = unsorted_string_list_lookup(&config_name_for_path, oldpath);
-	if (!path_option) {
+	path = get_name_for_path(oldpath);
+	if (!path) {
 		warning(_("Could not find section in .gitmodules where path=%s"), oldpath);
 		return -1;
 	}
 	strbuf_addstr(&entry, "submodule.");
-	strbuf_addstr(&entry, path_option->util);
+	strbuf_addstr(&entry, path);
 	strbuf_addstr(&entry, ".path");
 	if (git_config_set_in_file(".gitmodules", entry.buf, newpath) < 0) {
 		/* Maybe the user already did that, don't error out here */
@@ -89,7 +159,7 @@ int update_path_in_gitmodules(const char *oldpath, const char *newpath)
 int remove_path_from_gitmodules(const char *path)
 {
 	struct strbuf sect = STRBUF_INIT;
-	struct string_list_item *path_option;
+	const char *path_option;
 
 	if (!file_exists(".gitmodules")) /* Do nothing without .gitmodules */
 		return -1;
@@ -97,13 +167,13 @@ int remove_path_from_gitmodules(const char *path)
 	if (gitmodules_is_unmerged)
 		die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
 
-	path_option = unsorted_string_list_lookup(&config_name_for_path, path);
+	path_option = get_name_for_path(path);
 	if (!path_option) {
 		warning(_("Could not find section in .gitmodules where path=%s"), path);
 		return -1;
 	}
 	strbuf_addstr(&sect, "submodule.");
-	strbuf_addstr(&sect, path_option->util);
+	strbuf_addstr(&sect, path_option);
 	if (git_config_rename_section_in_file(".gitmodules", sect.buf, NULL) < 0) {
 		/* Maybe the user already did that, don't error out here */
 		warning(_("Could not remove .gitmodules entry for %s"), path);
@@ -165,12 +235,11 @@ done:
 void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 					     const char *path)
 {
-	struct string_list_item *path_option, *ignore_option;
-	path_option = unsorted_string_list_lookup(&config_name_for_path, path);
-	if (path_option) {
-		ignore_option = unsorted_string_list_lookup(&config_ignore_for_name, path_option->util);
-		if (ignore_option)
-			handle_ignore_submodules_arg(diffopt, ignore_option->util);
+	const char *name = get_name_for_path(path);
+	if (name) {
+		const char *ignore = get_ignore_for_name(name);
+		if (ignore)
+			handle_ignore_submodules_arg(diffopt, ignore);
 		else if (gitmodules_is_unmerged)
 			DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
 	}
@@ -221,7 +290,6 @@ void gitmodules_config(void)
 
 int parse_submodule_config_option(const char *var, const char *value)
 {
-	struct string_list_item *config;
 	const char *name, *key;
 	int namelen;
 
@@ -232,22 +300,14 @@ int parse_submodule_config_option(const char *var, const char *value)
 		if (!value)
 			return config_error_nonbool(var);
 
-		config = unsorted_string_list_lookup(&config_name_for_path, value);
-		if (config)
-			free(config->util);
-		else
-			config = string_list_append(&config_name_for_path, xstrdup(value));
-		config->util = xmemdupz(name, namelen);
+		set_name_for_path(value, name, namelen);
+
 	} else if (!strcmp(key, "fetchrecursesubmodules")) {
-		char *name_cstr = xmemdupz(name, namelen);
-		config = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name_cstr);
-		if (!config)
-			config = string_list_append(&config_fetch_recurse_submodules_for_name, name_cstr);
-		else
-			free(name_cstr);
-		config->util = (void *)(intptr_t)parse_fetch_recurse_submodules_arg(var, value);
+		int fetch_recurse = parse_fetch_recurse_submodules_arg(var, value);
+
+		set_fetch_recurse_for_name(name, namelen, fetch_recurse);
+
 	} else if (!strcmp(key, "ignore")) {
-		char *name_cstr;
 
 		if (!value)
 			return config_error_nonbool(var);
@@ -258,14 +318,7 @@ int parse_submodule_config_option(const char *var, const char *value)
 			return 0;
 		}
 
-		name_cstr = xmemdupz(name, namelen);
-		config = unsorted_string_list_lookup(&config_ignore_for_name, name_cstr);
-		if (config) {
-			free(config->util);
-			free(name_cstr);
-		} else
-			config = string_list_append(&config_ignore_for_name, name_cstr);
-		config->util = xstrdup(value);
+		set_ignore_for_name(name, namelen, value);
 		return 0;
 	}
 	return 0;
@@ -654,7 +707,7 @@ static void calculate_changed_submodule_paths(void)
 	struct argv_array argv = ARGV_ARRAY_INIT;
 
 	/* No need to check if there are no submodules configured */
-	if (!config_name_for_path.nr)
+	if (!get_name_for_path(NULL))
 		return;
 
 	init_revisions(&rev, NULL);
@@ -701,7 +754,7 @@ int fetch_populated_submodules(const struct argv_array *options,
 	int i, result = 0;
 	struct child_process cp;
 	struct argv_array argv = ARGV_ARRAY_INIT;
-	struct string_list_item *name_for_path;
+	const char *name_for_path;
 	const char *work_tree = get_git_work_tree();
 	if (!work_tree)
 		goto out;
@@ -733,18 +786,17 @@ int fetch_populated_submodules(const struct argv_array *options,
 			continue;
 
 		name = ce->name;
-		name_for_path = unsorted_string_list_lookup(&config_name_for_path, ce->name);
+		name_for_path = get_name_for_path(ce->name);
 		if (name_for_path)
-			name = name_for_path->util;
+			name = name_for_path;
 
 		default_argv = "yes";
 		if (command_line_option == RECURSE_SUBMODULES_DEFAULT) {
-			struct string_list_item *fetch_recurse_submodules_option;
-			fetch_recurse_submodules_option = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name);
-			if (fetch_recurse_submodules_option) {
-				if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_OFF)
+			int fetch_recurse_option = get_fetch_recurse_for_name(name);
+			if (fetch_recurse_option != RECURSE_SUBMODULES_NONE) {
+				if (fetch_recurse_option == RECURSE_SUBMODULES_OFF)
 					continue;
-				if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_ON_DEMAND) {
+				if (fetch_recurse_option == RECURSE_SUBMODULES_ON_DEMAND) {
 					if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 						continue;
 					default_argv = "on-demand";
-- 
2.0.0

[PATCH 4/5] use new config API for worktree configurations of submodules

[Heiko Voigt]

We remove the extracted functions and directly parse into and read out
of the cache. This allows us to have one unified way of accessing
submodule configuration values specific to single submodules. Regardless
whether we need to access a configuration from history or from the
worktree.

Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
---
 Documentation/technical/api-submodule-config.txt |  19 ++-
 builtin/checkout.c                               |   1 +
 diff.c                                           |   1 +
 submodule-config.c                               |  12 ++
 submodule-config.h                               |   1 +
 submodule.c                                      | 160 ++++-------------------
 submodule.h                                      |   1 -
 t/t7410-submodule-config.sh                      |  37 +++++-
 test-submodule-config.c                          |  10 ++
 9 files changed, 104 insertions(+), 138 deletions(-)

diff --git a/Documentation/technical/api-submodule-config.txt b/Documentation/technical/api-submodule-config.txt
index 2ff4907..2ea520a 100644
--- a/Documentation/technical/api-submodule-config.txt
+++ b/Documentation/technical/api-submodule-config.txt
@@ -10,10 +10,18 @@ submodule path or name.
 Usage
 -----
 
+To initialize the cache with configurations from the worktree the caller
+typically first calls `gitmodules_config()` to read values from the
+worktree .gitmodules and then to overlay the local git config values
+`parse_submodule_config_option()` from the config parsing
+infrastructure.
+
 The caller can look up information about submodules by using the
 `submodule_from_path()` or `submodule_from_name()` functions. They return
 a `struct submodule` which contains the values. The API automatically
-initializes and allocates the needed infrastructure on-demand.
+initializes and allocates the needed infrastructure on-demand. If the
+caller does only want to lookup values from revisions the initialization
+can be skipped.
 
 If the internal cache might grow too big or when the caller is done with
 the API, all internally cached values can be freed with submodule_free().
@@ -34,6 +42,11 @@ Functions
 
 	Use these to free the internally cached values.
 
+`int parse_submodule_config_option(const char *var, const char *value)`::
+
+	Can be passed to the config parsing infrastructure to parse
+	local (worktree) submodule configurations.
+
 `const struct submodule *submodule_from_path(const unsigned char *commit_sha1, const char *path)`::
 
 	Lookup values for one submodule by its commit_sha1 and path or
@@ -43,4 +56,8 @@ Functions
 
 	The same as above but lookup by name.
 
+If given the null_sha1 as commit_sha1 the local configuration of a
+submodule will be returned (e.g. consolidated values from local git
+configuration and the .gitmodules file in the worktree).
+
 For an example usage see test-submodule-config.c.
diff --git a/builtin/checkout.c b/builtin/checkout.c
index ff44921..4cb88e2 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -18,6 +18,7 @@
 #include "xdiff-interface.h"
 #include "ll-merge.h"
 #include "resolve-undo.h"
+#include "submodule-config.h"
 #include "submodule.h"
 #include "argv-array.h"
 
diff --git a/diff.c b/diff.c
index f66716f..485e0e6 100644
--- a/diff.c
+++ b/diff.c
@@ -13,6 +13,7 @@
 #include "utf8.h"
 #include "userdiff.h"
 #include "sigchain.h"
+#include "submodule-config.h"
 #include "submodule.h"
 #include "ll-merge.h"
 #include "string-list.h"
diff --git a/submodule-config.c b/submodule-config.c
index e7ca2b0..e445bf7 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -375,6 +375,18 @@ static void ensure_cache_init()
 	is_cache_init = 1;
 }
 
+int parse_submodule_config_option(const char *var, const char *value)
+{
+	struct parse_config_parameter parameter;
+	parameter.cache = &cache;
+	parameter.commit_sha1 = NULL;
+	parameter.gitmodules_sha1 = null_sha1;
+	parameter.overwrite = 1;
+
+	ensure_cache_init();
+	return parse_config(var, value, &parameter);
+}
+
 const struct submodule *submodule_from_name(const unsigned char *commit_sha1,
 		const char *name)
 {
diff --git a/submodule-config.h b/submodule-config.h
index 972496d..2083cb9 100644
--- a/submodule-config.h
+++ b/submodule-config.h
@@ -18,6 +18,7 @@ struct submodule {
 	unsigned char gitmodules_sha1[20];
 };
 
+int parse_submodule_config_option(const char *var, const char *value);
 const struct submodule *submodule_from_name(const unsigned char *commit_sha1,
 		const char *name);
 const struct submodule *submodule_from_path(const unsigned char *commit_sha1,
diff --git a/submodule.c b/submodule.c
index 86ec2e3..188b4d2 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1,4 +1,5 @@
 #include "cache.h"
+#include "submodule-config.h"
 #include "submodule.h"
 #include "dir.h"
 #include "diff.h"
@@ -12,9 +13,6 @@
 #include "argv-array.h"
 #include "blob.h"
 
-static struct string_list config_name_for_path;
-static struct string_list config_fetch_recurse_submodules_for_name;
-static struct string_list config_ignore_for_name;
 static int config_fetch_recurse_submodules = RECURSE_SUBMODULES_ON_DEMAND;
 static struct string_list changed_submodule_paths;
 static int initialized_fetch_ref_tips;
@@ -41,77 +39,6 @@ static int gitmodules_is_unmerged;
  */
 static int gitmodules_is_modified;
 
-static const char *get_name_for_path(const char *path)
-{
-	struct string_list_item *path_option;
-	if (path == NULL) {
-		if (config_name_for_path.nr > 0)
-			return config_name_for_path.items[0].util;
-		else
-			return NULL;
-	}
-	path_option = unsorted_string_list_lookup(&config_name_for_path, path);
-	if (!path_option)
-		return NULL;
-	return path_option->util;
-}
-
-static void set_name_for_path(const char *path, const char *name, int namelen)
-{
-	struct string_list_item *config;
-	config = unsorted_string_list_lookup(&config_name_for_path, path);
-	if (config)
-		free(config->util);
-	else
-		config = string_list_append(&config_name_for_path, xstrdup(path));
-	config->util = xmemdupz(name, namelen);
-}
-
-static const char *get_ignore_for_name(const char *name)
-{
-	struct string_list_item *ignore_option;
-	ignore_option = unsorted_string_list_lookup(&config_ignore_for_name, name);
-	if (!ignore_option)
-		return NULL;
-
-	return ignore_option->util;
-}
-
-static void set_ignore_for_name(const char *name, int namelen, const char *ignore)
-{
-	struct string_list_item *config;
-	char *name_cstr = xmemdupz(name, namelen);
-	config = unsorted_string_list_lookup(&config_ignore_for_name, name_cstr);
-	if (config) {
-		free(config->util);
-		free(name_cstr);
-	} else
-		config = string_list_append(&config_ignore_for_name, name_cstr);
-	config->util = xstrdup(ignore);
-}
-
-static int get_fetch_recurse_for_name(const char *name)
-{
-	struct string_list_item *fetch_recurse;
-	fetch_recurse = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name);
-	if (!fetch_recurse)
-		return RECURSE_SUBMODULES_NONE;
-
-	return (intptr_t) fetch_recurse->util;
-}
-
-static void set_fetch_recurse_for_name(const char *name, int namelen, int fetch_recurse)
-{
-	struct string_list_item *config;
-	char *name_cstr = xmemdupz(name, namelen);
-	config = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name_cstr);
-	if (!config)
-		config = string_list_append(&config_fetch_recurse_submodules_for_name, name_cstr);
-	else
-		free(name_cstr);
-	config->util = (void *)(intptr_t) fetch_recurse;
-}
-
 int is_staging_gitmodules_ok(void)
 {
 	return !gitmodules_is_modified;
@@ -125,7 +52,7 @@ int is_staging_gitmodules_ok(void)
 int update_path_in_gitmodules(const char *oldpath, const char *newpath)
 {
 	struct strbuf entry = STRBUF_INIT;
-	const char *path;
+	const struct submodule *submodule;
 
 	if (!file_exists(".gitmodules")) /* Do nothing without .gitmodules */
 		return -1;
@@ -133,13 +60,13 @@ int update_path_in_gitmodules(const char *oldpath, const char *newpath)
 	if (gitmodules_is_unmerged)
 		die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
 
-	path = get_name_for_path(oldpath);
-	if (!path) {
+	submodule = submodule_from_path(null_sha1, oldpath);
+	if (!submodule || !submodule->name) {
 		warning(_("Could not find section in .gitmodules where path=%s"), oldpath);
 		return -1;
 	}
 	strbuf_addstr(&entry, "submodule.");
-	strbuf_addstr(&entry, path);
+	strbuf_addstr(&entry, submodule->name);
 	strbuf_addstr(&entry, ".path");
 	if (git_config_set_in_file(".gitmodules", entry.buf, newpath) < 0) {
 		/* Maybe the user already did that, don't error out here */
@@ -159,7 +86,7 @@ int update_path_in_gitmodules(const char *oldpath, const char *newpath)
 int remove_path_from_gitmodules(const char *path)
 {
 	struct strbuf sect = STRBUF_INIT;
-	const char *path_option;
+	const struct submodule *submodule;
 
 	if (!file_exists(".gitmodules")) /* Do nothing without .gitmodules */
 		return -1;
@@ -167,13 +94,13 @@ int remove_path_from_gitmodules(const char *path)
 	if (gitmodules_is_unmerged)
 		die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
 
-	path_option = get_name_for_path(path);
-	if (!path_option) {
+	submodule = submodule_from_path(null_sha1, path);
+	if (!submodule || !submodule->name) {
 		warning(_("Could not find section in .gitmodules where path=%s"), path);
 		return -1;
 	}
 	strbuf_addstr(&sect, "submodule.");
-	strbuf_addstr(&sect, path_option);
+	strbuf_addstr(&sect, submodule->name);
 	if (git_config_rename_section_in_file(".gitmodules", sect.buf, NULL) < 0) {
 		/* Maybe the user already did that, don't error out here */
 		warning(_("Could not remove .gitmodules entry for %s"), path);
@@ -235,11 +162,10 @@ done:
 void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 					     const char *path)
 {
-	const char *name = get_name_for_path(path);
-	if (name) {
-		const char *ignore = get_ignore_for_name(name);
-		if (ignore)
-			handle_ignore_submodules_arg(diffopt, ignore);
+	const struct submodule *submodule = submodule_from_path(null_sha1, path);
+	if (submodule) {
+		if (submodule->ignore)
+			handle_ignore_submodules_arg(diffopt, submodule->ignore);
 		else if (gitmodules_is_unmerged)
 			DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
 	}
@@ -288,42 +214,6 @@ void gitmodules_config(void)
 	}
 }
 
-int parse_submodule_config_option(const char *var, const char *value)
-{
-	const char *name, *key;
-	int namelen;
-
-	if (parse_config_key(var, "submodule", &name, &namelen, &key) < 0 || !name)
-		return 0;
-
-	if (!strcmp(key, "path")) {
-		if (!value)
-			return config_error_nonbool(var);
-
-		set_name_for_path(value, name, namelen);
-
-	} else if (!strcmp(key, "fetchrecursesubmodules")) {
-		int fetch_recurse = parse_fetch_recurse_submodules_arg(var, value);
-
-		set_fetch_recurse_for_name(name, namelen, fetch_recurse);
-
-	} else if (!strcmp(key, "ignore")) {
-
-		if (!value)
-			return config_error_nonbool(var);
-
-		if (strcmp(value, "untracked") && strcmp(value, "dirty") &&
-		    strcmp(value, "all") && strcmp(value, "none")) {
-			warning("Invalid parameter \"%s\" for config option \"submodule.%s.ignore\"", value, var);
-			return 0;
-		}
-
-		set_ignore_for_name(name, namelen, value);
-		return 0;
-	}
-	return 0;
-}
-
 void handle_ignore_submodules_arg(struct diff_options *diffopt,
 				  const char *arg)
 {
@@ -707,7 +597,7 @@ static void calculate_changed_submodule_paths(void)
 	struct argv_array argv = ARGV_ARRAY_INIT;
 
 	/* No need to check if there are no submodules configured */
-	if (!get_name_for_path(NULL))
+	if (!submodule_from_path(NULL, NULL))
 		return;
 
 	init_revisions(&rev, NULL);
@@ -754,7 +644,6 @@ int fetch_populated_submodules(const struct argv_array *options,
 	int i, result = 0;
 	struct child_process cp;
 	struct argv_array argv = ARGV_ARRAY_INIT;
-	const char *name_for_path;
 	const char *work_tree = get_git_work_tree();
 	if (!work_tree)
 		goto out;
@@ -780,23 +669,26 @@ int fetch_populated_submodules(const struct argv_array *options,
 		struct strbuf submodule_git_dir = STRBUF_INIT;
 		struct strbuf submodule_prefix = STRBUF_INIT;
 		const struct cache_entry *ce = active_cache[i];
-		const char *git_dir, *name, *default_argv;
+		const char *git_dir, *default_argv;
+		const struct submodule *submodule;
 
 		if (!S_ISGITLINK(ce->ce_mode))
 			continue;
 
-		name = ce->name;
-		name_for_path = get_name_for_path(ce->name);
-		if (name_for_path)
-			name = name_for_path;
+		submodule = submodule_from_path(null_sha1, ce->name);
+		if (!submodule)
+			submodule = submodule_from_name(null_sha1, ce->name);
 
 		default_argv = "yes";
 		if (command_line_option == RECURSE_SUBMODULES_DEFAULT) {
-			int fetch_recurse_option = get_fetch_recurse_for_name(name);
-			if (fetch_recurse_option != RECURSE_SUBMODULES_NONE) {
-				if (fetch_recurse_option == RECURSE_SUBMODULES_OFF)
+			if (submodule &&
+			    submodule->fetch_recurse !=
+						RECURSE_SUBMODULES_NONE) {
+				if (submodule->fetch_recurse ==
+						RECURSE_SUBMODULES_OFF)
 					continue;
-				if (fetch_recurse_option == RECURSE_SUBMODULES_ON_DEMAND) {
+				if (submodule->fetch_recurse ==
+						RECURSE_SUBMODULES_ON_DEMAND) {
 					if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 						continue;
 					default_argv = "on-demand";
diff --git a/submodule.h b/submodule.h
index 920fef3..547219d 100644
--- a/submodule.h
+++ b/submodule.h
@@ -20,7 +20,6 @@ void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 		const char *path);
 int submodule_config(const char *var, const char *value, void *cb);
 void gitmodules_config(void);
-int parse_submodule_config_option(const char *var, const char *value);
 void handle_ignore_submodules_arg(struct diff_options *diffopt, const char *);
 int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg);
 void show_submodule_summary(FILE *f, const char *path,
diff --git a/t/t7410-submodule-config.sh b/t/t7410-submodule-config.sh
index ea453c5..1ec26c3 100755
--- a/t/t7410-submodule-config.sh
+++ b/t/t7410-submodule-config.sh
@@ -5,8 +5,8 @@
 
 test_description='Test submodules config cache infrastructure
 
-This test verifies that parsing .gitmodules configuration directly
-from the database works.
+This test verifies that parsing .gitmodules configurations directly
+from the database and from the worktree works.
 '
 
 TEST_NO_CREATE_REPO=1
@@ -70,4 +70,37 @@ test_expect_success 'error in one submodule config lets continue' '
 	)
 '
 
+cat >super/expect_url <<EOF
+Submodule url: 'git@somewhere.else.net:a.git' for path 'b'
+Submodule url: 'git@somewhere.else.net:submodule.git' for path 'submodule'
+EOF
+
+cat >super/expect_local_path <<EOF
+Submodule name: 'a' for path 'c'
+Submodule name: 'submodule' for path 'submodule'
+EOF
+
+test_expect_success 'reading of local configuration' '
+	(cd super &&
+		old_a=$(git config submodule.a.url) &&
+		old_submodule=$(git config submodule.submodule.url) &&
+		git config submodule.a.url git@somewhere.else.net:a.git &&
+		git config submodule.submodule.url git@somewhere.else.net:submodule.git &&
+		test-submodule-config --url \
+			"" b \
+			"" submodule \
+				>actual &&
+		test_cmp expect_url actual &&
+		git config submodule.a.path c &&
+		test-submodule-config \
+			"" c \
+			"" submodule \
+				>actual &&
+		test_cmp expect_local_path actual &&
+		git config submodule.a.url $old_a &&
+		git config submodule.submodule.url $old_submodule &&
+		git config --unset submodule.a.path c
+	)
+'
+
 test_done
diff --git a/test-submodule-config.c b/test-submodule-config.c
index 969d957..f47f046 100644
--- a/test-submodule-config.c
+++ b/test-submodule-config.c
@@ -4,6 +4,7 @@
 
 #include "cache.h"
 #include "submodule-config.h"
+#include "submodule.h"
 
 static void die_usage(int argc, char **argv, const char *msg)
 {
@@ -12,6 +13,11 @@ static void die_usage(int argc, char **argv, const char *msg)
 	exit(1);
 }
 
+static int git_test_config(const char *var, const char *value, void *cb)
+{
+	return parse_submodule_config_option(var, value);
+}
+
 int main(int argc, char **argv)
 {
 	char **arg = argv;
@@ -30,6 +36,10 @@ int main(int argc, char **argv)
 	if (my_argc % 2 != 0)
 		die_usage(argc, argv, "Wrong number of arguments.");
 
+	setup_git_directory();
+	gitmodules_config();
+	git_config(git_test_config, NULL);
+
 	while (*arg) {
 		unsigned char commit_sha1[20];
 		const struct submodule *submodule;
-- 
2.0.0

[PATCH 5/5] do not die on error of parsing fetchrecursesubmodules option

[Heiko Voigt]

We should not die when reading the submodule config cache since the user
might not be able to get out of that situation when the configuration is
part of the history.

We should handle this condition later when the value is about to be
used.

Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
---
 builtin/fetch.c             |  1 +
 submodule-config.c          | 29 ++++++++++++++++++++++++++++-
 submodule-config.h          |  1 +
 submodule.c                 | 15 ---------------
 submodule.h                 |  2 +-
 t/t7410-submodule-config.sh | 35 +++++++++++++++++++++++++++++++++++
 6 files changed, 66 insertions(+), 17 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 55f457c..706326f 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -12,6 +12,7 @@
 #include "parse-options.h"
 #include "sigchain.h"
 #include "transport.h"
+#include "submodule-config.h"
 #include "submodule.h"
 #include "connected.h"
 #include "argv-array.h"
diff --git a/submodule-config.c b/submodule-config.c
index e445bf7..437fbdb 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -199,6 +199,30 @@ static struct submodule *lookup_or_create_by_name(struct submodule_cache *cache,
 	return submodule;
 }
 
+static int parse_fetch_recurse(const char *opt, const char *arg,
+			       int die_on_error)
+{
+	switch (git_config_maybe_bool(opt, arg)) {
+	case 1:
+		return RECURSE_SUBMODULES_ON;
+	case 0:
+		return RECURSE_SUBMODULES_OFF;
+	default:
+		if (!strcmp(arg, "on-demand"))
+			return RECURSE_SUBMODULES_ON_DEMAND;
+
+		if (die_on_error)
+			die("bad %s argument: %s", opt, arg);
+		else
+			return RECURSE_SUBMODULES_ERROR;
+	}
+}
+
+int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg)
+{
+	return parse_fetch_recurse(opt, arg, 1);
+}
+
 static void warn_multiple_config(const unsigned char *commit_sha1,
 				 const char *name, const char *option)
 {
@@ -250,6 +274,8 @@ static int parse_config(const char *var, const char *value, void *data)
 		submodule->path = strbuf_detach(&path, NULL);
 		cache_put_path(me->cache, submodule);
 	} else if (!strcmp(item.buf, "fetchrecursesubmodules")) {
+		/* when parsing worktree configurations we can die early */
+		int die_on_error = is_null_sha1(me->gitmodules_sha1);
 		if (!me->overwrite &&
 		    submodule->fetch_recurse != RECURSE_SUBMODULES_NONE) {
 			warn_multiple_config(me->commit_sha1, submodule->name,
@@ -257,7 +283,8 @@ static int parse_config(const char *var, const char *value, void *data)
 			goto release_return;
 		}
 
-		submodule->fetch_recurse = parse_fetch_recurse_submodules_arg(var, value);
+		submodule->fetch_recurse = parse_fetch_recurse(var, value,
+								die_on_error);
 	} else if (!strcmp(item.buf, "ignore")) {
 		struct strbuf ignore = STRBUF_INIT;
 		if (!me->overwrite && submodule->ignore != NULL) {
diff --git a/submodule-config.h b/submodule-config.h
index 2083cb9..58afc83 100644
--- a/submodule-config.h
+++ b/submodule-config.h
@@ -18,6 +18,7 @@ struct submodule {
 	unsigned char gitmodules_sha1[20];
 };
 
+int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg);
 int parse_submodule_config_option(const char *var, const char *value);
 const struct submodule *submodule_from_name(const unsigned char *commit_sha1,
 		const char *name);
diff --git a/submodule.c b/submodule.c
index 188b4d2..75f502f 100644
--- a/submodule.c
+++ b/submodule.c
@@ -288,21 +288,6 @@ static void print_submodule_summary(struct rev_info *rev, FILE *f,
 	strbuf_release(&sb);
 }
 
-int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg)
-{
-	switch (git_config_maybe_bool(opt, arg)) {
-	case 1:
-		return RECURSE_SUBMODULES_ON;
-	case 0:
-		return RECURSE_SUBMODULES_OFF;
-	default:
-		if (!strcmp(arg, "on-demand"))
-			return RECURSE_SUBMODULES_ON_DEMAND;
-		/* TODO: remove the die for history parsing here */
-		die("bad %s argument: %s", opt, arg);
-	}
-}
-
 void show_submodule_summary(FILE *f, const char *path,
 		const char *line_prefix,
 		unsigned char one[20], unsigned char two[20],
diff --git a/submodule.h b/submodule.h
index 547219d..5507c3d 100644
--- a/submodule.h
+++ b/submodule.h
@@ -5,6 +5,7 @@ struct diff_options;
 struct argv_array;
 
 enum {
+	RECURSE_SUBMODULES_ERROR = -3,
 	RECURSE_SUBMODULES_NONE = -2,
 	RECURSE_SUBMODULES_ON_DEMAND = -1,
 	RECURSE_SUBMODULES_OFF = 0,
@@ -21,7 +22,6 @@ void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 int submodule_config(const char *var, const char *value, void *cb);
 void gitmodules_config(void);
 void handle_ignore_submodules_arg(struct diff_options *diffopt, const char *);
-int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg);
 void show_submodule_summary(FILE *f, const char *path,
 		const char *line_prefix,
 		unsigned char one[20], unsigned char two[20],
diff --git a/t/t7410-submodule-config.sh b/t/t7410-submodule-config.sh
index 1ec26c3..4a837af 100755
--- a/t/t7410-submodule-config.sh
+++ b/t/t7410-submodule-config.sh
@@ -103,4 +103,39 @@ test_expect_success 'reading of local configuration' '
 	)
 '
 
+cat >super/expect_fetchrecurse_die.err <<EOF
+fatal: bad submodule.submodule.fetchrecursesubmodules argument: blabla
+EOF
+
+test_expect_success 'local error in fetchrecursesubmodule dies early' '
+	(cd super &&
+		git config submodule.submodule.fetchrecursesubmodules blabla &&
+		test_must_fail test-submodule-config \
+			"" b \
+			"" submodule \
+				>actual.out 2>actual.err &&
+		touch expect_fetchrecurse_die.out &&
+		test_cmp expect_fetchrecurse_die.out actual.out  &&
+		test_cmp expect_fetchrecurse_die.err actual.err  &&
+		git config --unset submodule.submodule.fetchrecursesubmodules
+	)
+'
+
+test_expect_success 'error in history in fetchrecursesubmodule lets continue' '
+	(cd super &&
+		git config -f .gitmodules \
+			submodule.submodule.fetchrecursesubmodules blabla &&
+		git add .gitmodules &&
+		git config --unset -f .gitmodules \
+			submodule.submodule.fetchrecursesubmodules &&
+		git commit -m "add error in fetchrecursesubmodules" &&
+		test-submodule-config \
+			HEAD b \
+			HEAD submodule \
+				>actual &&
+		test_cmp expect_error actual  &&
+		git reset --hard HEAD^
+	)
+'
+
 test_done
-- 
2.0.0

Re: [PATCH 2/5] implement submodule config cache for lookup of submodule names

[W. Trevor King]

[-- Attachment #1: Type: text/plain, Size: 982 bytes --]

On Thu, Jun 05, 2014 at 08:07:50AM +0200, Heiko Voigt wrote:
> +The caller can look up information about submodules by using the
> +`submodule_from_path()` or `submodule_from_name()` functions.

That's for an already-known submodule.  Do we need a way to list
submodules (e.g. for 'submodule foreach' style operations) or is the
preferred way to do that just walking the tree looking for gitlinks?
The cases where .gitmodules would lead you astray (e.g. via sloppy
commits after removing a submodule) are:

* Listing a submodule that wasn't in the tree anymore.  Easy to check
  for and ignore.

* Not listing a submodule that is in the tree.  You'd need to walk the
  tree to check for this, but it's a pretty broken situation already,
  so I'd be fine just ignoring the orphaned gitlink.

Cheers,
Trevor

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For more information, see http://en.wikipedia.org/wiki/Pretty_Good_Privacy

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Re: Re: [PATCH 2/5] implement submodule config cache for lookup of submodule names

[Heiko Voigt]

On Thu, Jun 05, 2014 at 10:46:10AM -0700, W. Trevor King wrote:
> On Thu, Jun 05, 2014 at 08:07:50AM +0200, Heiko Voigt wrote:
> > +The caller can look up information about submodules by using the
> > +`submodule_from_path()` or `submodule_from_name()` functions.
> 
> That's for an already-known submodule.  Do we need a way to list
> submodules (e.g. for 'submodule foreach' style operations) or is the
> preferred way to do that just walking the tree looking for gitlinks?
> The cases where .gitmodules would lead you astray (e.g. via sloppy
> commits after removing a submodule) are:
> 
> * Listing a submodule that wasn't in the tree anymore.  Easy to check
>   for and ignore.
> 
> * Not listing a submodule that is in the tree.  You'd need to walk the
>   tree to check for this, but it's a pretty broken situation already,
>   so I'd be fine just ignoring the orphaned gitlink.

Currently there is no need to list the submodules in a .gitmodule file.
We currently always begin from the gitlink and try to do things. If we
have enough information thats fine we go ahead, if not we stop (or
skip?) the submodule. So for already initialized submodules it is even
ok to not have a .gitmodules entry at all and we can still go ahead with
most operations. Here we should not be too picky, I think.

The only use-case I can think of is for checking whether .gitmodules
contains any extra unneeded values. But on the other hand that is not
so easy. Since .gitmodules are just config files they can contain user
defined values. That is ok.

So in summary: Yes the preferred way to list submodules is via iterating
the gitlinks and I do not think we need a way to iterate through the
.gitmodules file (at least not for the use-cases we currently need this
for).

Cheers Heiko

Re: [PATCH 1/5] hashmap: add enum for hashmap free_entries option

[Karsten Blees]

Am 05.06.2014 08:06, schrieb Heiko Voigt:
> This allows a reader to immediately know which options can be used and
> what this parameter is about.
> 
[...]
> -void hashmap_free(struct hashmap *map, int free_entries)
> +void hashmap_free(struct hashmap *map, enum hashmap_free_options free_entries)
[...]
>  
> +enum hashmap_free_options {
> +	HASHMAP_NO_FREE_ENTRIES = 0,
> +	HASHMAP_FREE_ENTRIES = 1,
> +};

This was meant as a boolean parameter. Would it make sense to have

enum boolean {
	false,
	true
};

or similar in some central place?

Note that an earlier version took a function pointer, and you could pass stdlib's free() in the common case, or a special free routine for nested entry structures, or NULL to do the cleanup yourself.

Re: [PATCH 2/5] implement submodule config cache for lookup of submodule names

[Eric Sunshine]

On Thu, Jun 5, 2014 at 2:07 AM, Heiko Voigt <hvoigt@hvoigt.net> wrote:
> This submodule configuration cache allows us to lazily read .gitmodules
> configurations by commit into a runtime cache which can then be used to
> easily lookup values from it. Currently only the values for path or name
> are stored but it can be extended for any value needed.
>
> [...]
>
> Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
> ---
> diff --git a/t/t7410-submodule-config.sh b/t/t7410-submodule-config.sh
> new file mode 100755
> index 0000000..ea453c5
> --- /dev/null
> +++ b/t/t7410-submodule-config.sh
> @@ -0,0 +1,73 @@
> +#!/bin/sh
> +#
> +# Copyright (c) 2014 Heiko Voigt
> +#
> +
> +test_description='Test submodules config cache infrastructure
> +
> +This test verifies that parsing .gitmodules configuration directly
> +from the database works.
> +'
> +
> +TEST_NO_CREATE_REPO=1
> +. ./test-lib.sh
> +
> +test_expect_success 'submodule config cache setup' '
> +       mkdir submodule &&
> +       (cd submodule &&
> +               git init

Broken &&-chain.

> +               echo a >a &&
> +               git add . &&
> +               git commit -ma
> +       ) &&
> +       mkdir super &&
> +       (cd super &&
> +               git init &&
> +               git submodule add ../submodule &&
> +               git submodule add ../submodule a &&
> +               git commit -m "add as submodule and as a" &&
> +               git mv a b &&
> +               git commit -m "move a to b"
> +       )
> +'
> +
> +cat >super/expect <<EOF
> +Submodule name: 'a' for path 'a'
> +Submodule name: 'a' for path 'b'
> +Submodule name: 'submodule' for path 'submodule'
> +Submodule name: 'submodule' for path 'submodule'
> +EOF
> +
> +test_expect_success 'test parsing of submodule config' '
> +       (cd super &&
> +               test-submodule-config \
> +                       HEAD^ a \
> +                       HEAD b \
> +                       HEAD^ submodule \
> +                       HEAD submodule \
> +                               >actual &&
> +               test_cmp expect actual
> +       )
> +'
> +
> +cat >super/expect_error <<EOF
> +Submodule name: 'a' for path 'b'
> +Submodule name: 'submodule' for path 'submodule'
> +EOF
> +
> +test_expect_success 'error in one submodule config lets continue' '
> +       (cd super &&
> +               cp .gitmodules .gitmodules.bak &&
> +               echo "  value = \"" >>.gitmodules &&
> +               git add .gitmodules &&
> +               mv .gitmodules.bak .gitmodules &&
> +               git commit -m "add error" &&
> +               test-submodule-config \
> +                       HEAD b \
> +                       HEAD submodule \
> +                               >actual &&
> +               test_cmp expect_error actual
> +       )
> +'
> +
> +test_done

Re: [PATCH 1/5] hashmap: add enum for hashmap free_entries option

[Heiko Voigt]

On Fri, Jun 06, 2014 at 07:52:03PM +0200, Karsten Blees wrote:
> Am 05.06.2014 08:06, schrieb Heiko Voigt:
> > This allows a reader to immediately know which options can be used and
> > what this parameter is about.
> > 
> [...]
> > -void hashmap_free(struct hashmap *map, int free_entries)
> > +void hashmap_free(struct hashmap *map, enum hashmap_free_options free_entries)
> [...]
> >  
> > +enum hashmap_free_options {
> > +	HASHMAP_NO_FREE_ENTRIES = 0,
> > +	HASHMAP_FREE_ENTRIES = 1,
> > +};
> 
> This was meant as a boolean parameter. Would it make sense to have
> 
> enum boolean {
> 	false,
> 	true
> };
> 
> or similar in some central place?

The intention of Jonathans critique here[1] was that you do not see what
this parameter does on the callsite. I.e.:

	hashmap_free(&map, 1);

compared to

	hashmap_free(&map, HASHMAP_FREE_ENTRIES);

A boolean basically transfers the same information and would not help
the reader here.

Cheers Heiko

[1] http://article.gmane.org/gmane.comp.version-control.git/243917

Re: [PATCH 2/5] implement submodule config cache for lookup of submodule names

[Heiko Voigt]

On Sun, Jun 08, 2014 at 05:04:44AM -0400, Eric Sunshine wrote:
> On Thu, Jun 5, 2014 at 2:07 AM, Heiko Voigt <hvoigt@hvoigt.net> wrote:
> > This submodule configuration cache allows us to lazily read .gitmodules
> > configurations by commit into a runtime cache which can then be used to
> > easily lookup values from it. Currently only the values for path or name
> > are stored but it can be extended for any value needed.
> >
> > [...]
> >
> > Signed-off-by: Heiko Voigt <hvoigt@hvoigt.net>
> > ---
> > diff --git a/t/t7410-submodule-config.sh b/t/t7410-submodule-config.sh
> > new file mode 100755
> > index 0000000..ea453c5
> > --- /dev/null
> > +++ b/t/t7410-submodule-config.sh
> > @@ -0,0 +1,73 @@
> > +#!/bin/sh
> > +#
> > +# Copyright (c) 2014 Heiko Voigt
> > +#
> > +
> > +test_description='Test submodules config cache infrastructure
> > +
> > +This test verifies that parsing .gitmodules configuration directly
> > +from the database works.
> > +'
> > +
> > +TEST_NO_CREATE_REPO=1
> > +. ./test-lib.sh
> > +
> > +test_expect_success 'submodule config cache setup' '
> > +       mkdir submodule &&
> > +       (cd submodule &&
> > +               git init
> 
> Broken &&-chain.

Will fix. Thanks for catching.

Cheers Heiko

Re: [PATCH 1/5] hashmap: add enum for hashmap free_entries option

[Karsten Blees]

Am 10.06.2014 12:17, schrieb Heiko Voigt:
> On Fri, Jun 06, 2014 at 07:52:03PM +0200, Karsten Blees wrote:
>> Am 05.06.2014 08:06, schrieb Heiko Voigt:
>>> This allows a reader to immediately know which options can be used and
>>> what this parameter is about.
>>>
>> [...]
>>> -void hashmap_free(struct hashmap *map, int free_entries)
>>> +void hashmap_free(struct hashmap *map, enum hashmap_free_options free_entries)
>> [...]
>>>  
>>> +enum hashmap_free_options {
>>> +	HASHMAP_NO_FREE_ENTRIES = 0,
>>> +	HASHMAP_FREE_ENTRIES = 1,
>>> +};
>>
>> This was meant as a boolean parameter. Would it make sense to have
>>
>> enum boolean {
>> 	false,
>> 	true
>> };
>>
>> or similar in some central place?
> 
> The intention of Jonathans critique here[1] was that you do not see what
> this parameter does on the callsite. I.e.:
> 
> 	hashmap_free(&map, 1);
> 
> compared to
> 
> 	hashmap_free(&map, HASHMAP_FREE_ENTRIES);
> 
> A boolean basically transfers the same information and would not help
> the reader here.
> 
> Cheers Heiko
> 
> [1] http://article.gmane.org/gmane.comp.version-control.git/243917
> 

There are languages where you can have e.g. 'hashmap_free(..., free_entries: true)'. In C, however, you do not see what a parameter does at the call site. This is a general language feature, reducing redundancy and keeping it short and concise. IMO there's no reason to treat boolean parameters differently.

Using an enum suggests that there is more to the parameter than a simple yes/no decision, underpinned by naming it '...options' (plural). I find this rather confusing.

Finally, enums share a global namespace, which means long identifiers, provoking additional line breaks and thus reducing readability. Not a problem with hashmap_free per se, but if you do the same for e.g. 'free_util' in string-list.[ch] or 'icase' in name-hash.c, I suspect it'll get pretty ugly.

So please lets not spoil the global namespace with a thousand different names for 0/1. Using enums for >= tristate values and bit flags is fine, but inventing enums for every simple boolean in the system is bound to end in chaos.

Just my 2c
Karsten

Re: [PATCH 1/5] hashmap: add enum for hashmap free_entries option

[Junio C Hamano]

Karsten Blees <karsten.blees@gmail.com> writes:

> Am 10.06.2014 12:17, schrieb Heiko Voigt:
>> The intention of Jonathans critique here[1] was that you do not see what
>> this parameter does on the callsite. I.e.:
>> 
>> 	hashmap_free(&map, 1);
>> 
>> compared to
>> 
>> 	hashmap_free(&map, HASHMAP_FREE_ENTRIES);
>> 
>> A boolean basically transfers the same information and would not help
>> the reader here.
>> 
>> Cheers Heiko
>> 
>> [1] http://article.gmane.org/gmane.comp.version-control.git/243917
>> 
>
> There are languages where you can have e.g. 'hashmap_free(...,
> free_entries: true)'. In C, however, you do not see what a
> parameter does at the call site. This is a general language
> feature, reducing redundancy and keeping it short and concise. IMO
> there's no reason to treat boolean parameters differently.

But given that you are writing in C, is any of that relevant?  We do
want to keep our call-sites readable and understandable, and 1 or
true would not help, unless (1) you are the one who wrote the
function and know that 1 means free the entries, or (2) the API is
so widely used and everybody knows what 1 means free the entries.

Re: [PATCH 2/5] implement submodule config cache for lookup of submodule names

[Junio C Hamano]

Heiko Voigt <hvoigt@hvoigt.net> writes:

> ...
> +static int is_cache_init = 0;

Please don't initialise variables in the .bss to zero by hand.

> + ...
> +	warning("%s:.gitmodules, multiple configurations found for "
> +			"submodule.%s.%s. Skipping second one!",
> +			commit_string, name, option);
> +}
> + ...
> +		if (strcmp(value, "untracked") && strcmp(value, "dirty") &&
> +		    strcmp(value, "all") && strcmp(value, "none")) {
> +			warning("Invalid parameter \"%s\" for config option "
> +					"\"submodule.%s.ignore\"", value, var);
> +			goto release_return;
> +		}

These two look inconsistent in different ways.  I think we typically
quote the names like so:

	warning("I have trouble with variable '%s' somehow", var);

Re: [PATCH 0/5] submodule config lookup API

[Junio C Hamano]

Heiko Voigt <hvoigt@hvoigt.net> writes:

>  t/t7410-submodule-config.sh                      | 141 ++++++++

We already use 7410 for something else in 'pu'; please avoid dups
waiting to happen.

>  test-hashmap.c                                   |   6 +-
>  test-submodule-config.c                          |  74 ++++
>  18 files changed, 791 insertions(+), 107 deletions(-)
>  create mode 100644 Documentation/technical/api-submodule-config.txt
>  create mode 100644 submodule-config.c
>  create mode 100644 submodule-config.h
>  create mode 100755 t/t7410-submodule-config.sh
>  create mode 100644 test-submodule-config.c

Re: [PATCH 0/5] submodule config lookup API

[Junio C Hamano]

Hmph, this seems to conflict in a meaningful (and painful) way with
Jens's "jl/submodule-recursive-checkout".

Re: [PATCH 0/5] submodule config lookup API

[Jens Lehmann]

Am 13.06.2014 00:04, schrieb Junio C Hamano:
> Hmph, this seems to conflict in a meaningful (and painful) way with
> Jens's "jl/submodule-recursive-checkout".

Then you might wanna drop my series for now, I need to rebase it
above Heiko's series myself to make new submodules work anyway.

Re: [PATCH 0/5] submodule config lookup API

[Junio C Hamano]

Jens Lehmann <Jens.Lehmann@web.de> writes:

> Am 13.06.2014 00:04, schrieb Junio C Hamano:
>> Hmph, this seems to conflict in a meaningful (and painful) way with
>> Jens's "jl/submodule-recursive-checkout".
>
> Then you might wanna drop my series for now, I need to rebase it
> above Heiko's series myself to make new submodules work anyway.

Thanks, that makes my pile smaller by one topic ;-)

Re: [PATCH 2/5] implement submodule config cache for lookup of submodule names

[Heiko Voigt]

On Thu, Jun 12, 2014 at 02:58:20PM -0700, Junio C Hamano wrote:
> Heiko Voigt <hvoigt@hvoigt.net> writes:
> 
> > ...
> > +static int is_cache_init = 0;
> 
> Please don't initialise variables in the .bss to zero by hand.

Ok will remove that.

> > + ...
> > +	warning("%s:.gitmodules, multiple configurations found for "
> > +			"submodule.%s.%s. Skipping second one!",
> > +			commit_string, name, option);
> > +}
> > + ...
> > +		if (strcmp(value, "untracked") && strcmp(value, "dirty") &&
> > +		    strcmp(value, "all") && strcmp(value, "none")) {
> > +			warning("Invalid parameter \"%s\" for config option "
> > +					"\"submodule.%s.ignore\"", value, var);
> > +			goto release_return;
> > +		}
> 
> These two look inconsistent in different ways.  I think we typically
> quote the names like so:
> 
> 	warning("I have trouble with variable '%s' somehow", var);

Ok will change the quotation for the variable and parameter names.

Here is the fixup[1] I will queue in my branch.

Cheers Heiko

[1] ---8<----
Subject: [PATCH] fixup! implement submodule config cache for lookup of
 submodule names

---
 submodule-config.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/submodule-config.c b/submodule-config.c
index 437fbdb..f330ccc 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -26,7 +26,7 @@ struct submodule_entry {
 };
 
 static struct submodule_cache cache;
-static int is_cache_init = 0;
+static int is_cache_init;
 
 static int config_path_cmp(const struct submodule_entry *a,
 			   const struct submodule_entry *b,
@@ -230,7 +230,7 @@ static void warn_multiple_config(const unsigned char *commit_sha1,
 	if (commit_sha1)
 		commit_string = sha1_to_hex(commit_sha1);
 	warning("%s:.gitmodules, multiple configurations found for "
-			"submodule.%s.%s. Skipping second one!",
+			"'submodule.%s.%s'. Skipping second one!",
 			commit_string, name, option);
 }
 
@@ -298,8 +298,8 @@ static int parse_config(const char *var, const char *value, void *data)
 		}
 		if (strcmp(value, "untracked") && strcmp(value, "dirty") &&
 		    strcmp(value, "all") && strcmp(value, "none")) {
-			warning("Invalid parameter \"%s\" for config option "
-					"\"submodule.%s.ignore\"", value, var);
+			warning("Invalid parameter '%s' for config option "
+					"'submodule.%s.ignore'", value, var);
 			goto release_return;
 		}
 
-- 
2.0.0

Re: [PATCH 0/5] submodule config lookup API

[Heiko Voigt]

On Thu, Jun 12, 2014 at 02:59:23PM -0700, Junio C Hamano wrote:
> Heiko Voigt <hvoigt@hvoigt.net> writes:
> 
> >  t/t7410-submodule-config.sh                      | 141 ++++++++
> 
> We already use 7410 for something else in 'pu'; please avoid dups
> waiting to happen.

Sorry about that. Should I use 7411 even though that other series is
still work in progress?

Re: [PATCH 0/5] submodule config lookup API

[Junio C Hamano]

Heiko Voigt <hvoigt@hvoigt.net> writes:

> On Thu, Jun 12, 2014 at 02:59:23PM -0700, Junio C Hamano wrote:
>> Heiko Voigt <hvoigt@hvoigt.net> writes:
>> 
>> >  t/t7410-submodule-config.sh                      | 141 ++++++++
>> 
>> We already use 7410 for something else in 'pu'; please avoid dups
>> waiting to happen.
>
> Sorry about that. Should I use 7411 even though that other series is
> still work in progress?

Surely.

What would be an alternative?  Tell the other series to rename?  ;-)

Re: [PATCH 1/5] hashmap: add enum for hashmap free_entries option

[Karsten Blees]

Am 12.06.2014 21:12, schrieb Junio C Hamano:
> Karsten Blees <karsten.blees@gmail.com> writes:
> 
>> Am 10.06.2014 12:17, schrieb Heiko Voigt:
>>> The intention of Jonathans critique here[1] was that you do not see what
>>> this parameter does on the callsite. I.e.:
>>>
>>> 	hashmap_free(&map, 1);
>>>
>>> compared to
>>>
>>> 	hashmap_free(&map, HASHMAP_FREE_ENTRIES);
>>>
>>> A boolean basically transfers the same information and would not help
>>> the reader here.
>>>
>>> Cheers Heiko
>>>
>>> [1] http://article.gmane.org/gmane.comp.version-control.git/243917
>>>
>>
>> There are languages where you can have e.g. 'hashmap_free(...,
>> free_entries: true)'. In C, however, you do not see what a
>> parameter does at the call site. This is a general language
>> feature, reducing redundancy and keeping it short and concise. IMO
>> there's no reason to treat boolean parameters differently.
> 
> But given that you are writing in C, is any of that relevant?  We do
> want to keep our call-sites readable and understandable, 

But in C, readable and understandable are opposite goals.
'Understandable' entails long, redundant identifiers, automatically
decreasing readability. The compiler doesn't care about either, so
we could just as well keep the C part short and use plain English
for understandability:

  /* free maps, except file entries (owned by istate->cache) */
  hashmap_free(&istate->name_hash, 0);
  hashmap_free(&istate->dir_hash, 1);

Note that this not only explains what we're doing, but also why.

> and 1 or
> true would not help, unless (1) you are the one who wrote the
> function and know that 1 means free the entries, or (2) the API is
> so widely used and everybody knows what 1 means free the entries.
> 

or (3) you need to check the function declaration or documentation
anyway, to understand what the non-boolean parameters do.

E.g. consider this (from remote.c:1186):

  dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);

vs.

  dst_value = resolve_ref_unsafe(matched_src->name, sha1,
                                 RESOLVE_REF_UNSAFE_FOR_READING,
                                 &flag);

That's three lines vs. one, "RESOLVE_REF_UNSAFE_" is completely
redundant with the function name, "FOR_READING" isn't particularly
enlightening either, and you still don't know what the other three
parameters do. IMO this would be much better:

  /* fully resolve matched symref to resolved ref name and sha1 */
  dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);

So veterans highly familiar with the code can stick to the C part
without being distracted by unnecessary line breaks and
SHOUTED_IDENTIFIERS, while everyone else may find the explanation
helpful.


As I said, using enums for hashmap_free isn't a problem on its own.
However, the accepted solution for booleans in the git code base
seems to be to use just an int and 0/1.

For consistency, we could of course change string_list*,
resolve_ref*, index_file_exists etc. as well.

...and in turn 'extern int ignore_case' (because it gets passed to
index_file_exists)?

...and in turn all other boolean config variables?

I don't think this would be an improvement, though.

Re: Re: [PATCH 0/5] submodule config lookup API

[Heiko Voigt]

On Mon, Jun 16, 2014 at 10:58:25AM -0700, Junio C Hamano wrote:
> Heiko Voigt <hvoigt@hvoigt.net> writes:
> 
> > On Thu, Jun 12, 2014 at 02:59:23PM -0700, Junio C Hamano wrote:
> >> Heiko Voigt <hvoigt@hvoigt.net> writes:
> >> 
> >> >  t/t7410-submodule-config.sh                      | 141 ++++++++
> >> 
> >> We already use 7410 for something else in 'pu'; please avoid dups
> >> waiting to happen.
> >
> > Sorry about that. Should I use 7411 even though that other series is
> > still work in progress?
> 
> Surely.
> 
> What would be an alternative?  Tell the other series to rename?  ;-)

Don't know. Of course not ;-) Will rename.

Re: Re: [PATCH 1/5] hashmap: add enum for hashmap free_entries option

[Heiko Voigt]

On Tue, Jun 17, 2014 at 10:30:35AM +0200, Karsten Blees wrote:
> Am 12.06.2014 21:12, schrieb Junio C Hamano:
> > Karsten Blees <karsten.blees@gmail.com> writes:
> > 
> >> Am 10.06.2014 12:17, schrieb Heiko Voigt:
> >>> The intention of Jonathans critique here[1] was that you do not see what
> >>> this parameter does on the callsite. I.e.:
> >>>
> >>> 	hashmap_free(&map, 1);
> >>>
> >>> compared to
> >>>
> >>> 	hashmap_free(&map, HASHMAP_FREE_ENTRIES);
> >>>
> >>> A boolean basically transfers the same information and would not help
> >>> the reader here.
> >>>
> >>> Cheers Heiko
> >>>
> >>> [1] http://article.gmane.org/gmane.comp.version-control.git/243917
> >>>
> >>
> >> There are languages where you can have e.g. 'hashmap_free(...,
> >> free_entries: true)'. In C, however, you do not see what a
> >> parameter does at the call site. This is a general language
> >> feature, reducing redundancy and keeping it short and concise. IMO
> >> there's no reason to treat boolean parameters differently.
> > 
> > But given that you are writing in C, is any of that relevant?  We do
> > want to keep our call-sites readable and understandable, 
> 
> But in C, readable and understandable are opposite goals.
> 'Understandable' entails long, redundant identifiers, automatically
> decreasing readability. The compiler doesn't care about either, so
> we could just as well keep the C part short and use plain English
> for understandability:
> 
>   /* free maps, except file entries (owned by istate->cache) */
>   hashmap_free(&istate->name_hash, 0);
>   hashmap_free(&istate->dir_hash, 1);
> 
> Note that this not only explains what we're doing, but also why.
> 
> > and 1 or
> > true would not help, unless (1) you are the one who wrote the
> > function and know that 1 means free the entries, or (2) the API is
> > so widely used and everybody knows what 1 means free the entries.
> > 
> 
> or (3) you need to check the function declaration or documentation
> anyway, to understand what the non-boolean parameters do.
> 
> E.g. consider this (from remote.c:1186):
> 
>   dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
> 
> vs.
> 
>   dst_value = resolve_ref_unsafe(matched_src->name, sha1,
>                                  RESOLVE_REF_UNSAFE_FOR_READING,
>                                  &flag);
> 
> That's three lines vs. one, "RESOLVE_REF_UNSAFE_" is completely
> redundant with the function name, "FOR_READING" isn't particularly
> enlightening either, and you still don't know what the other three
> parameters do. IMO this would be much better:
> 
>   /* fully resolve matched symref to resolved ref name and sha1 */
>   dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
> 
> So veterans highly familiar with the code can stick to the C part
> without being distracted by unnecessary line breaks and
> SHOUTED_IDENTIFIERS, while everyone else may find the explanation
> helpful.
> 
> 
> As I said, using enums for hashmap_free isn't a problem on its own.
> However, the accepted solution for booleans in the git code base
> seems to be to use just an int and 0/1.
> 
> For consistency, we could of course change string_list*,
> resolve_ref*, index_file_exists etc. as well.
> 
> ...and in turn 'extern int ignore_case' (because it gets passed to
> index_file_exists)?
> 
> ...and in turn all other boolean config variables?
> 
> I don't think this would be an improvement, though.

If this is such a controversial change for you I will drop this patch in
the next round. I think it would make the callsite more readable without
adding much clutter but I am fine with it either way.

Re: [PATCH 1/5] hashmap: add enum for hashmap free_entries option

[Junio C Hamano]

Heiko Voigt <hvoigt@hvoigt.net> writes:

> If this is such a controversial change for you I will drop this patch in
> the next round. I think it would make the callsite more readable without
> adding much clutter but I am fine with it either way.

OK, let's do that.