[PATCHv5 0/5] repo-local env vars handling

[PATCHv5 0/5] repo-local env vars handling

[Giuseppe Bilotta]

Changes from the previous iteration:

* the first two patches were squashed together
* local_repo_env_size is now a #define to the number of non-NULL entries in 
  the list of repo-local env vars. The last patch is consequently adjusted.

Giuseppe Bilotta (5):
  Refactor list of of repo-local env vars
  rev-parse: --local-env-vars option
  shell setup: clear_local_git_env() function
  submodules: ensure clean environment when operating in a submodule
  is_submodule_modified(): clear environment properly

 Documentation/git-rev-parse.txt |    6 ++++++
 builtin-rev-parse.c             |    8 ++++++++
 cache.h                         |    8 ++++++++
 connect.c                       |   14 ++------------
 environment.c                   |   15 +++++++++++++++
 git-sh-setup.sh                 |    7 +++++++
 git-submodule.sh                |   20 ++++++++++----------
 submodule.c                     |   21 +++++++++++----------
 8 files changed, 67 insertions(+), 32 deletions(-)

[PATCHv5 1/5] Refactor list of of repo-local env vars

[Giuseppe Bilotta]

Move the list of GIT_* environment variables that are local to a
repository into a static list in environment.c, as it is also
useful elsewhere. Also add the missing GIT_CONFIG variable to the
list.

Make it easy to use the list both by NULL-termination and by size;
the latter (excluding the terminating NULL) is stored in the
local_repo_env_size define.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
---
 cache.h       |    8 ++++++++
 connect.c     |   14 ++------------
 environment.c |   15 +++++++++++++++
 3 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/cache.h b/cache.h
index d454b7e..0832ee9 100644
--- a/cache.h
+++ b/cache.h
@@ -388,6 +388,14 @@ static inline enum object_type object_type(unsigned int mode)
 #define GIT_NOTES_REF_ENVIRONMENT "GIT_NOTES_REF"
 #define GIT_NOTES_DEFAULT_REF "refs/notes/commits"
 
+/* Repository-local GIT_* environment variables */
+/* The array is NULL-terminated to simplify its usage in contexts such
+   environment creation or simple walk of the list.
+   The number of non-NULL entries is stored in the following define
+   to simplify preallocation of arrays that need to extend it */
+#define local_repo_env_size 8
+extern const char *const local_repo_env[local_repo_env_size+1];
+
 extern int is_bare_repository_cfg;
 extern int is_bare_repository(void);
 extern int is_inside_git_dir(void);
diff --git a/connect.c b/connect.c
index 9f39038..323a771 100644
--- a/connect.c
+++ b/connect.c
@@ -582,18 +582,8 @@ struct child_process *git_connect(int fd[2], const char *url_orig,
 		*arg++ = host;
 	}
 	else {
-		/* remove these from the environment */
-		const char *env[] = {
-			ALTERNATE_DB_ENVIRONMENT,
-			DB_ENVIRONMENT,
-			GIT_DIR_ENVIRONMENT,
-			GIT_WORK_TREE_ENVIRONMENT,
-			GRAFT_ENVIRONMENT,
-			INDEX_ENVIRONMENT,
-			NO_REPLACE_OBJECTS_ENVIRONMENT,
-			NULL
-		};
-		conn->env = env;
+		/* remove repo-local variables from the environment */
+		conn->env = local_repo_env;
 		conn->use_shell = 1;
 	}
 	*arg++ = cmd.buf;
diff --git a/environment.c b/environment.c
index 739ec27..b3e9e8c 100644
--- a/environment.c
+++ b/environment.c
@@ -63,6 +63,21 @@ static char *work_tree;
 static const char *git_dir;
 static char *git_object_dir, *git_index_file, *git_refs_dir, *git_graft_file;
 
+/* Repository-local GIT_* environment variables */
+/* Remember to update local_repo_env_size in cache.h when the size
+   of the list changes */
+const char *const local_repo_env[local_repo_env_size+1] = {
+	ALTERNATE_DB_ENVIRONMENT,
+	CONFIG_ENVIRONMENT,
+	DB_ENVIRONMENT,
+	GIT_DIR_ENVIRONMENT,
+	GIT_WORK_TREE_ENVIRONMENT,
+	GRAFT_ENVIRONMENT,
+	INDEX_ENVIRONMENT,
+	NO_REPLACE_OBJECTS_ENVIRONMENT,
+	NULL
+};
+
 static void setup_git_env(void)
 {
 	git_dir = getenv(GIT_DIR_ENVIRONMENT);
-- 
1.7.0.212.g5b851b.dirty

[PATCHv5 2/5] rev-parse: --local-env-vars option

[Giuseppe Bilotta]

This prints the list of repo-local environment variables.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
---
 Documentation/git-rev-parse.txt |    6 ++++++
 builtin-rev-parse.c             |    8 ++++++++
 2 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index 1a613aa..8db600f 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -148,6 +148,12 @@ shown.  If the pattern does not contain a globbing character (`?`,
 --is-bare-repository::
 	When the repository is bare print "true", otherwise "false".
 
+--local-env-vars::
+	List the GIT_* environment variables that are local to the
+	repository (e.g. GIT_DIR or GIT_WORK_TREE, but not GIT_EDITOR).
+	Only the names of the variables are listed, not their value,
+	even if they are set.
+
 --short::
 --short=number::
 	Instead of outputting the full SHA1 values of object names try to
diff --git a/builtin-rev-parse.c b/builtin-rev-parse.c
index a8c5043..ab7b520 100644
--- a/builtin-rev-parse.c
+++ b/builtin-rev-parse.c
@@ -455,7 +455,15 @@ int cmd_rev_parse(int argc, const char **argv, const char *prefix)
 	if (argc > 1 && !strcmp("--sq-quote", argv[1]))
 		return cmd_sq_quote(argc - 2, argv + 2);
 
+	if (argc > 0 && !strcmp("--local-env-vars", argv[1])) {
+		unsigned int i = 0;
+		const char *var;
+		while (var = local_repo_env[i++])
+			printf("%s\n", var);
+		return 0;
+	}
 	if (argc > 1 && !strcmp("-h", argv[1]))
+
 		usage(builtin_rev_parse_usage);
 
 	prefix = setup_git_directory();
-- 
1.7.0.212.g5b851b.dirty

[PATCHv5 3/5] shell setup: clear_local_git_env() function

[Giuseppe Bilotta]

Introduce an auxiliary function to clear all repo-local environment
variables. This should be invoked by any shell script that switches
repository during execution, to ensure that the environment is clean
and that things such as the git dir and worktree are set up correctly.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
---
 git-sh-setup.sh |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index 7a09566..6131670 100644
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -172,6 +172,13 @@ get_author_ident_from_commit () {
 	LANG=C LC_ALL=C sed -ne "$pick_author_script"
 }
 
+# Clear repo-local GIT_* environment variables. Useful when switching to
+# another repository (e.g. when entering a submodule). See also the env
+# list in git_connect()
+clear_local_git_env() {
+	unset $(git rev-parse --local-env-vars)
+}
+
 # Make sure we are in a valid repository of a vintage we understand,
 # if we require to be in a git repository.
 if test -z "$NONGIT_OK"
-- 
1.7.0.212.g5b851b.dirty

[PATCHv5 4/5] submodules: ensure clean environment when operating in a submodule

[Giuseppe Bilotta]

git-submodule used to take care of clearing GIT_DIR whenever it operated
on a submodule index or configuration, but forgot to unset GIT_WORK_TREE
or other repo-local variables. This would lead to failures e.g. when
GIT_WORK_TREE was set.

This only happened in very unusual contexts such as operating on the
main worktree from outside of it, but since "git-gui: set GIT_DIR and
GIT_WORK_TREE after setup" (a9fa11fe5bd5978bb) such failures could also
be provoked by invoking an external tool such as "git submodule update"
from the Git Gui in a standard setup.

Solve by using the newly introduced clear_local_git_env() shell function
to ensure that all repo-local environment variables are unset.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
---
 git-submodule.sh |   20 ++++++++++----------
 1 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/git-submodule.sh b/git-submodule.sh
index 5869c00..1ea4143 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -222,7 +222,7 @@ cmd_add()
 
 		module_clone "$path" "$realrepo" "$reference" || exit
 		(
-			unset GIT_DIR
+			clear_local_git_env
 			cd "$path" &&
 			# ash fails to wordsplit ${branch:+-b "$branch"...}
 			case "$branch" in
@@ -278,7 +278,7 @@ cmd_foreach()
 			name=$(module_name "$path")
 			(
 				prefix="$prefix$path/"
-				unset GIT_DIR
+				clear_local_git_env
 				cd "$path" &&
 				eval "$@" &&
 				if test -n "$recursive"
@@ -434,7 +434,7 @@ cmd_update()
 			module_clone "$path" "$url" "$reference"|| exit
 			subsha1=
 		else
-			subsha1=$(unset GIT_DIR; cd "$path" &&
+			subsha1=$(clear_local_git_env; cd "$path" &&
 				git rev-parse --verify HEAD) ||
 			die "Unable to find current revision in submodule path '$path'"
 		fi
@@ -454,7 +454,7 @@ cmd_update()
 
 			if test -z "$nofetch"
 			then
-				(unset GIT_DIR; cd "$path" &&
+				(clear_local_git_env; cd "$path" &&
 					git-fetch) ||
 				die "Unable to fetch in submodule path '$path'"
 			fi
@@ -477,14 +477,14 @@ cmd_update()
 				;;
 			esac
 
-			(unset GIT_DIR; cd "$path" && $command "$sha1") ||
+			(clear_local_git_env; cd "$path" && $command "$sha1") ||
 			die "Unable to $action '$sha1' in submodule path '$path'"
 			say "Submodule path '$path': $msg '$sha1'"
 		fi
 
 		if test -n "$recursive"
 		then
-			(unset GIT_DIR; cd "$path" && cmd_update $orig_args) ||
+			(clear_local_git_env; cd "$path" && cmd_update $orig_args) ||
 			die "Failed to recurse into submodule path '$path'"
 		fi
 	done
@@ -492,7 +492,7 @@ cmd_update()
 
 set_name_rev () {
 	revname=$( (
-		unset GIT_DIR
+		clear_local_git_env
 		cd "$1" && {
 			git describe "$2" 2>/dev/null ||
 			git describe --tags "$2" 2>/dev/null ||
@@ -760,7 +760,7 @@ cmd_status()
 		else
 			if test -z "$cached"
 			then
-				sha1=$(unset GIT_DIR; cd "$path" && git rev-parse --verify HEAD)
+				sha1=$(clear_local_git_env; cd "$path" && git rev-parse --verify HEAD)
 				set_name_rev "$path" "$sha1"
 			fi
 			say "+$sha1 $displaypath$revname"
@@ -770,7 +770,7 @@ cmd_status()
 		then
 			(
 				prefix="$displaypath/"
-				unset GIT_DIR
+				clear_local_git_env
 				cd "$path" &&
 				cmd_status $orig_args
 			) ||
@@ -821,7 +821,7 @@ cmd_sync()
 		if test -e "$path"/.git
 		then
 		(
-			unset GIT_DIR
+			clear_local_git_env
 			cd "$path"
 			remote=$(get_default_remote)
 			say "Synchronizing submodule url for '$name'"
-- 
1.7.0.212.g5b851b.dirty

[PATCHv5 5/5] is_submodule_modified(): clear environment properly

[Giuseppe Bilotta]

Rather than only clearing GIT_INDEX_FILE, take the list of environment
variables to clear from local_repo_env, appending the settings for
GIT_DIR and GIT_WORK_TREE.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
---
 submodule.c |   21 +++++++++++----------
 1 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/submodule.c b/submodule.c
index 7d70c4f..3c34d39 100644
--- a/submodule.c
+++ b/submodule.c
@@ -124,15 +124,19 @@ void show_submodule_summary(FILE *f, const char *path,
 int is_submodule_modified(const char *path)
 {
 	int len;
+	unsigned int i = 0;
 	struct child_process cp;
 	const char *argv[] = {
 		"status",
 		"--porcelain",
 		NULL,
 	};
-	char *env[4];
+	const char *env[local_repo_env_size+3];
 	struct strbuf buf = STRBUF_INIT;
 
+	for ( ; i < local_repo_env_size; ++i)
+		env[i] = local_repo_env[i];
+
 	strbuf_addf(&buf, "%s/.git/", path);
 	if (!is_directory(buf.buf)) {
 		strbuf_release(&buf);
@@ -143,16 +147,14 @@ int is_submodule_modified(const char *path)
 	strbuf_reset(&buf);
 
 	strbuf_addf(&buf, "GIT_WORK_TREE=%s", path);
-	env[0] = strbuf_detach(&buf, NULL);
+	env[i++] = strbuf_detach(&buf, NULL);
 	strbuf_addf(&buf, "GIT_DIR=%s/.git", path);
-	env[1] = strbuf_detach(&buf, NULL);
-	strbuf_addf(&buf, "GIT_INDEX_FILE");
-	env[2] = strbuf_detach(&buf, NULL);
-	env[3] = NULL;
+	env[i++] = strbuf_detach(&buf, NULL);
+	env[i] = NULL;
 
 	memset(&cp, 0, sizeof(cp));
 	cp.argv = argv;
-	cp.env = (const char *const *)env;
+	cp.env = env;
 	cp.git_cmd = 1;
 	cp.no_stdin = 1;
 	cp.out = -1;
@@ -165,9 +167,8 @@ int is_submodule_modified(const char *path)
 	if (finish_command(&cp))
 		die("git status --porcelain failed");
 
-	free(env[0]);
-	free(env[1]);
-	free(env[2]);
+	free((char *)env[--i]);
+	free((char *)env[--i]);
 	strbuf_release(&buf);
 	return len != 0;
 }
-- 
1.7.0.212.g5b851b.dirty

Re: [PATCHv5 2/5] rev-parse: --local-env-vars option

[Heiko Voigt]

On Thu, Feb 25, 2010 at 12:34:15AM +0100, Giuseppe Bilotta wrote:
> This prints the list of repo-local environment variables.
> 
> Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
> ---
[...]
> diff --git a/builtin-rev-parse.c b/builtin-rev-parse.c
> index a8c5043..ab7b520 100644
> --- a/builtin-rev-parse.c
> +++ b/builtin-rev-parse.c
[...]
>  	if (argc > 1 && !strcmp("-h", argv[1]))
> +
>  		usage(builtin_rev_parse_usage);

You probably forgot to remove that empty line there.

cheers Heiko