[PATCH v3 00/19] Make git-pull a builtin

[PATCH v3 00/19] Make git-pull a builtin

[Paul Tan]

This is a re-roll of [v2]. Thanks Junio, Stefan for the reviews last round.

Previous versions:

[v1] http://thread.gmane.org/gmane.comp.version-control.git/269258
[v2] http://thread.gmane.org/gmane.comp.version-control.git/270639

git-pull is a commonly executed command to check for new changes in the
upstream repository and, if there are, fetch and integrate them into the
current branch. Currently it is implemented by the shell script git-pull.sh.
However, compared to C, shell scripts have certain deficiencies -- they need to
spawn a lot of processes, introduce a lot of dependencies and cannot take
advantage of git's internal caches.

This series rewrites git-pull.sh into a C builtin, thus improving its
performance and portability. It is part of my GSoC project to rewrite git-pull
and git-am into builtins[1].

[1] https://gist.github.com/pyokagan/1b7b0d1f4dab6ba3cef1


Paul Tan (19):
  parse-options-cb: implement parse_opt_passthru()
  parse-options-cb: implement parse_opt_passthru_argv()
  argv-array: implement argv_array_pushv()
  pull: implement skeletal builtin pull
  pull: implement fetch + merge
  pull: pass verbosity, --progress flags to fetch and merge
  pull: pass git-merge's options to git-merge
  pull: pass git-fetch's options to git-fetch
  pull: error on no merge candidates
  pull: support pull.ff config
  pull: check if in unresolved merge state
  pull: fast-forward working tree if head is updated
  pull: implement pulling into an unborn branch
  pull: set reflog message
  pull: teach git pull about --rebase
  pull: configure --rebase via branch.<name>.rebase or pull.rebase
  pull --rebase: exit early when the working directory is dirty
  pull --rebase: error on no merge candidate cases
  pull: remove redirection to git-pull.sh

 Documentation/technical/api-argv-array.txt    |   3 +
 Documentation/technical/api-parse-options.txt |  13 +
 Makefile                                      |   2 +-
 advice.c                                      |   8 +
 advice.h                                      |   1 +
 argv-array.c                                  |   6 +
 argv-array.h                                  |   1 +
 builtin.h                                     |   1 +
 builtin/pull.c                                | 881 ++++++++++++++++++++++++++
 git-pull.sh => contrib/examples/git-pull.sh   |   0
 git.c                                         |   1 +
 parse-options-cb.c                            |  69 ++
 parse-options.h                               |   6 +
 13 files changed, 991 insertions(+), 1 deletion(-)
 create mode 100644 builtin/pull.c
 rename git-pull.sh => contrib/examples/git-pull.sh (100%)

-- 
2.1.4

[PATCH v3 01/19] parse-options-cb: implement parse_opt_passthru()

[Paul Tan]

Certain git commands, such as git-pull, are simply wrappers around other
git commands like git-fetch, git-merge and git-rebase. As such, these
wrapper commands will typically need to "pass through" command-line
options of the commands they wrap.

Implement the parse_opt_passthru() parse-options callback, which will
reconstruct the command-line option into an char* string, such that it
can be passed to another git command.

Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v3
    
    * Reverted back to returning newly-allocated strings. Junio raised the
      concern that it may not be such a good idea to burden the users of the
      API to always use X.buf to access the string. Personally I believe
      that memory management safety is usually more important, but I don't
      have strong feelings about this.
    
    * Extracted out the "option reconstruction" logic into a private
      function so that it can be shared with parse_opt_passthru_argv() in
      the next patch.
    
    * Introduced the OPT_PASSTHRU() macro and documented it in
      Documentation/technical/api-parse-options.txt. This macro relieves the
      user of having to specify OPTION_CALLBACK and parse_opt_passthru() for
      every option.
    
    * The function used to be named parse_opt_pass_strbuf() to save
      horizontal space, but then again parse_opt_passthru() is probably a
      better name.
    
    * Added comment to the docstring that the callback should only be used
      for options where the last one wins.

 Documentation/technical/api-parse-options.txt |  7 ++++
 parse-options-cb.c                            | 49 +++++++++++++++++++++++++++
 parse-options.h                               |  3 ++
 3 files changed, 59 insertions(+)

diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt
index 1f2db31..85d10ab 100644
--- a/Documentation/technical/api-parse-options.txt
+++ b/Documentation/technical/api-parse-options.txt
@@ -212,6 +212,13 @@ There are some macros to easily define options:
 	Use it to hide deprecated options that are still to be recognized
 	and ignored silently.
 
+`OPT_PASSTHRU(short, long, &char_var, arg_str, description, flags)`::
+	Introduce an option that will be reconstructed into a char* string,
+	which must be initialized to NULL. This is useful when you need to
+	pass the command-line option to another command. Any previous value
+	will be overwritten, so this should only be used for options where
+	the last one specified on the command line wins.
+
 
 The last element of the array must be `OPT_END()`.
 
diff --git a/parse-options-cb.c b/parse-options-cb.c
index be8c413..68bc593 100644
--- a/parse-options-cb.c
+++ b/parse-options-cb.c
@@ -134,3 +134,52 @@ int parse_opt_noop_cb(const struct option *opt, const char *arg, int unset)
 {
 	return 0;
 }
+
+/**
+ * Recreates the command-line option in the strbuf.
+ */
+static int recreate_opt(struct strbuf *sb, const struct option *opt,
+		const char *arg, int unset)
+{
+	strbuf_reset(sb);
+
+	if (opt->long_name) {
+		strbuf_addstr(sb, unset ? "--no-" : "--");
+		strbuf_addstr(sb, opt->long_name);
+		if (arg) {
+			strbuf_addch(sb, '=');
+			strbuf_addstr(sb, arg);
+		}
+	} else if (opt->short_name && !unset) {
+		strbuf_addch(sb, '-');
+		strbuf_addch(sb, opt->short_name);
+		if (arg)
+			strbuf_addstr(sb, arg);
+	} else
+		return -1;
+
+	return 0;
+}
+
+/**
+ * For an option opt, recreates the command-line option in opt->value which
+ * must be an char* initialized to NULL. This is useful when we need to pass
+ * the command-line option to another command. Since any previous value will be
+ * overwritten, this callback should only be used for options where the last
+ * one wins.
+ */
+int parse_opt_passthru(const struct option *opt, const char *arg, int unset)
+{
+	static struct strbuf sb = STRBUF_INIT;
+	char **opt_value = opt->value;
+
+	if (recreate_opt(&sb, opt, arg, unset) < 0)
+		return -1;
+
+	if (*opt_value)
+		free(*opt_value);
+
+	*opt_value = strbuf_detach(&sb, NULL);
+
+	return 0;
+}
diff --git a/parse-options.h b/parse-options.h
index c71e9da..5b0f886 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -224,6 +224,7 @@ extern int parse_opt_with_commit(const struct option *, const char *, int);
 extern int parse_opt_tertiary(const struct option *, const char *, int);
 extern int parse_opt_string_list(const struct option *, const char *, int);
 extern int parse_opt_noop_cb(const struct option *, const char *, int);
+extern int parse_opt_passthru(const struct option *, const char *, int);
 
 #define OPT__VERBOSE(var, h)  OPT_COUNTUP('v', "verbose", (var), (h))
 #define OPT__QUIET(var, h)    OPT_COUNTUP('q', "quiet",   (var), (h))
@@ -242,5 +243,7 @@ extern int parse_opt_noop_cb(const struct option *, const char *, int);
 	OPT_COLOR_FLAG(0, "color", (var), (h))
 #define OPT_COLUMN(s, l, v, h) \
 	{ OPTION_CALLBACK, (s), (l), (v), N_("style"), (h), PARSE_OPT_OPTARG, parseopt_column_callback }
+#define OPT_PASSTHRU(s, l, v, a, h, f) \
+	{ OPTION_CALLBACK, (s), (l), (v), (a), (h), (f), parse_opt_passthru }
 
 #endif
-- 
2.1.4

[PATCH v3 02/19] parse-options-cb: implement parse_opt_passthru_argv()

[Paul Tan]

Certain git commands, such as git-pull, are simply wrappers around other
git commands like git-fetch, git-merge and git-rebase. As such, these
wrapper commands will typically need to "pass through" command-line
options of the commands they wrap.

Implement the parse_opt_passthru_argv() parse-options callback, which
will reconstruct all the provided command-line options into an
argv_array, such that it can be passed to another git command. This is
useful for passing command-line options that can be specified multiple
times.

Helped-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v3
    
    * Renamed function to the more descriptive parse_opt_passthru_argv().
    
    * Introduced and documented OPT_PASSTHRU_ARGV() macro, which saves the
      user from having to specify OPTION_CALLBACK and
      parse_opt_passthru_argv() for each option.

 Documentation/technical/api-parse-options.txt |  6 ++++++
 parse-options-cb.c                            | 20 ++++++++++++++++++++
 parse-options.h                               |  3 +++
 3 files changed, 29 insertions(+)

diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt
index 85d10ab..0b0ab01 100644
--- a/Documentation/technical/api-parse-options.txt
+++ b/Documentation/technical/api-parse-options.txt
@@ -219,6 +219,12 @@ There are some macros to easily define options:
 	will be overwritten, so this should only be used for options where
 	the last one specified on the command line wins.
 
+`OPT_PASSTHRU_ARGV(short, long, &argv_array_var, arg_str, description, flags)`::
+	Introduce an option where all instances of it on the command-line will
+	be reconstructed into an argv_array. This is useful when you need to
+	pass the command-line option, which can be specified multiple times,
+	to another command.
+
 
 The last element of the array must be `OPT_END()`.
 
diff --git a/parse-options-cb.c b/parse-options-cb.c
index 68bc593..5ab6ed6 100644
--- a/parse-options-cb.c
+++ b/parse-options-cb.c
@@ -4,6 +4,7 @@
 #include "commit.h"
 #include "color.h"
 #include "string-list.h"
+#include "argv-array.h"
 
 /*----- some often used options -----*/
 
@@ -183,3 +184,22 @@ int parse_opt_passthru(const struct option *opt, const char *arg, int unset)
 
 	return 0;
 }
+
+/**
+ * For an option opt, recreate the command-line option, appending it to
+ * opt->value which must be a argv_array. This is useful when we need to pass
+ * the command-line option, which can be specified multiple times, to another
+ * command.
+ */
+int parse_opt_passthru_argv(const struct option *opt, const char *arg, int unset)
+{
+	static struct strbuf sb = STRBUF_INIT;
+	struct argv_array *opt_value = opt->value;
+
+	if (recreate_opt(&sb, opt, arg, unset) < 0)
+		return -1;
+
+	argv_array_push(opt_value, sb.buf);
+
+	return 0;
+}
diff --git a/parse-options.h b/parse-options.h
index 5b0f886..aba06688 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -225,6 +225,7 @@ extern int parse_opt_tertiary(const struct option *, const char *, int);
 extern int parse_opt_string_list(const struct option *, const char *, int);
 extern int parse_opt_noop_cb(const struct option *, const char *, int);
 extern int parse_opt_passthru(const struct option *, const char *, int);
+extern int parse_opt_passthru_argv(const struct option *, const char *, int);
 
 #define OPT__VERBOSE(var, h)  OPT_COUNTUP('v', "verbose", (var), (h))
 #define OPT__QUIET(var, h)    OPT_COUNTUP('q', "quiet",   (var), (h))
@@ -245,5 +246,7 @@ extern int parse_opt_passthru(const struct option *, const char *, int);
 	{ OPTION_CALLBACK, (s), (l), (v), N_("style"), (h), PARSE_OPT_OPTARG, parseopt_column_callback }
 #define OPT_PASSTHRU(s, l, v, a, h, f) \
 	{ OPTION_CALLBACK, (s), (l), (v), (a), (h), (f), parse_opt_passthru }
+#define OPT_PASSTHRU_ARGV(s, l, v, a, h, f) \
+	{ OPTION_CALLBACK, (s), (l), (v), (a), (h), (f), parse_opt_passthru_argv }
 
 #endif
-- 
2.1.4

[PATCH v3 03/19] argv-array: implement argv_array_pushv()

[Paul Tan]

When we have a null-terminated array, it would be useful to convert it
or append it to an argv_array for further manipulation.

Implement argv_array_pushv() which will push a null-terminated array of
strings on to an argv_array.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 Documentation/technical/api-argv-array.txt | 3 +++
 argv-array.c                               | 6 ++++++
 argv-array.h                               | 1 +
 3 files changed, 10 insertions(+)

diff --git a/Documentation/technical/api-argv-array.txt b/Documentation/technical/api-argv-array.txt
index 1a79781..8076172 100644
--- a/Documentation/technical/api-argv-array.txt
+++ b/Documentation/technical/api-argv-array.txt
@@ -46,6 +46,9 @@ Functions
 	Format a string and push it onto the end of the array. This is a
 	convenience wrapper combining `strbuf_addf` and `argv_array_push`.
 
+`argv_array_pushv`::
+	Push a null-terminated array of strings onto the end of the array.
+
 `argv_array_pop`::
 	Remove the final element from the array. If there are no
 	elements in the array, do nothing.
diff --git a/argv-array.c b/argv-array.c
index 256741d..eaed477 100644
--- a/argv-array.c
+++ b/argv-array.c
@@ -49,6 +49,12 @@ void argv_array_pushl(struct argv_array *array, ...)
 	va_end(ap);
 }
 
+void argv_array_pushv(struct argv_array *array, const char **argv)
+{
+	for (; *argv; argv++)
+		argv_array_push(array, *argv);
+}
+
 void argv_array_pop(struct argv_array *array)
 {
 	if (!array->argc)
diff --git a/argv-array.h b/argv-array.h
index c65e6e8..a2fa0aa 100644
--- a/argv-array.h
+++ b/argv-array.h
@@ -17,6 +17,7 @@ __attribute__((format (printf,2,3)))
 void argv_array_pushf(struct argv_array *, const char *fmt, ...);
 LAST_ARG_MUST_BE_NULL
 void argv_array_pushl(struct argv_array *, ...);
+void argv_array_pushv(struct argv_array *, const char **);
 void argv_array_pop(struct argv_array *);
 void argv_array_clear(struct argv_array *);
 
-- 
2.1.4

[PATCH v3 04/19] pull: implement skeletal builtin pull

[Paul Tan]

For the purpose of rewriting git-pull.sh into a C builtin, implement a
skeletal builtin/pull.c that redirects to $GIT_EXEC_PATH/git-pull.sh if
the environment variable _GIT_USE_BUILTIN_PULL is not defined. This
allows us to fall back on the functional git-pull.sh when running the
test suite for tests that depend on a working git-pull implementation.

This redirection should be removed when all the features of git-pull.sh
have been re-implemented in builtin/pull.c.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v3
    
    * style fixes

 Makefile       |  1 +
 builtin.h      |  1 +
 builtin/pull.c | 33 +++++++++++++++++++++++++++++++++
 git.c          |  1 +
 4 files changed, 36 insertions(+)
 create mode 100644 builtin/pull.c

diff --git a/Makefile b/Makefile
index 54ec511..2057a9d 100644
--- a/Makefile
+++ b/Makefile
@@ -877,6 +877,7 @@ BUILTIN_OBJS += builtin/pack-refs.o
 BUILTIN_OBJS += builtin/patch-id.o
 BUILTIN_OBJS += builtin/prune-packed.o
 BUILTIN_OBJS += builtin/prune.o
+BUILTIN_OBJS += builtin/pull.o
 BUILTIN_OBJS += builtin/push.o
 BUILTIN_OBJS += builtin/read-tree.o
 BUILTIN_OBJS += builtin/receive-pack.o
diff --git a/builtin.h b/builtin.h
index b87df70..ea3c834 100644
--- a/builtin.h
+++ b/builtin.h
@@ -98,6 +98,7 @@ extern int cmd_pack_redundant(int argc, const char **argv, const char *prefix);
 extern int cmd_patch_id(int argc, const char **argv, const char *prefix);
 extern int cmd_prune(int argc, const char **argv, const char *prefix);
 extern int cmd_prune_packed(int argc, const char **argv, const char *prefix);
+extern int cmd_pull(int argc, const char **argv, const char *prefix);
 extern int cmd_push(int argc, const char **argv, const char *prefix);
 extern int cmd_read_tree(int argc, const char **argv, const char *prefix);
 extern int cmd_receive_pack(int argc, const char **argv, const char *prefix);
diff --git a/builtin/pull.c b/builtin/pull.c
new file mode 100644
index 0000000..cabeed4
--- /dev/null
+++ b/builtin/pull.c
@@ -0,0 +1,33 @@
+/*
+ * Builtin "git pull"
+ *
+ * Based on git-pull.sh by Junio C Hamano
+ *
+ * Fetch one or more remote refs and merge it/them into the current HEAD.
+ */
+#include "cache.h"
+#include "builtin.h"
+#include "parse-options.h"
+#include "exec_cmd.h"
+
+static const char * const pull_usage[] = {
+	NULL
+};
+
+static struct option pull_options[] = {
+	OPT_END()
+};
+
+int cmd_pull(int argc, const char **argv, const char *prefix)
+{
+	if (!getenv("_GIT_USE_BUILTIN_PULL")) {
+		const char *path = mkpath("%s/git-pull", git_exec_path());
+
+		if (sane_execvp(path, (char **)argv) < 0)
+			die_errno("could not exec %s", path);
+	}
+
+	argc = parse_options(argc, argv, prefix, pull_options, pull_usage, 0);
+
+	return 0;
+}
diff --git a/git.c b/git.c
index 44374b1..e7a7713 100644
--- a/git.c
+++ b/git.c
@@ -445,6 +445,7 @@ static struct cmd_struct commands[] = {
 	{ "pickaxe", cmd_blame, RUN_SETUP },
 	{ "prune", cmd_prune, RUN_SETUP },
 	{ "prune-packed", cmd_prune_packed, RUN_SETUP },
+	{ "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
 	{ "push", cmd_push, RUN_SETUP },
 	{ "read-tree", cmd_read_tree, RUN_SETUP },
 	{ "receive-pack", cmd_receive_pack },
-- 
2.1.4

[PATCH v3 05/19] pull: implement fetch + merge

[Paul Tan]

Implement the fetch + merge functionality of git-pull, by first running
git-fetch with the repo and refspecs provided on the command line, then
running git-merge on FETCH_HEAD to merge the fetched refs into the
current branch.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v3
    
    * Catch bug where there is are refspecs but no repo.

 builtin/pull.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/builtin/pull.c b/builtin/pull.c
index cabeed4..9157536 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -9,8 +9,10 @@
 #include "builtin.h"
 #include "parse-options.h"
 #include "exec_cmd.h"
+#include "run-command.h"
 
 static const char * const pull_usage[] = {
+	N_("git pull [options] [<repository> [<refspec>...]]"),
 	NULL
 };
 
@@ -18,8 +20,61 @@ static struct option pull_options[] = {
 	OPT_END()
 };
 
+/**
+ * Parses argv into [<repo> [<refspecs>...]], returning their values in `repo`
+ * as a string and `refspecs` as a null-terminated array of strings. If `repo`
+ * is not provided in argv, it is set to NULL.
+ */
+static void parse_repo_refspecs(int argc, const char **argv, const char **repo,
+		const char ***refspecs)
+{
+	if (argc > 0) {
+		*repo = *argv++;
+		argc--;
+	} else
+		*repo = NULL;
+	*refspecs = argv;
+}
+
+/**
+ * Runs git-fetch, returning its exit status. `repo` and `refspecs` are the
+ * repository and refspecs to fetch, or NULL if they are not provided.
+ */
+static int run_fetch(const char *repo, const char **refspecs)
+{
+	struct argv_array args = ARGV_ARRAY_INIT;
+	int ret;
+
+	argv_array_pushl(&args, "fetch", "--update-head-ok", NULL);
+	if (repo) {
+		argv_array_push(&args, repo);
+		argv_array_pushv(&args, refspecs);
+	} else if (*refspecs)
+		die("BUG: refspecs without repo?");
+	ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
+	argv_array_clear(&args);
+	return ret;
+}
+
+/**
+ * Runs git-merge, returning its exit status.
+ */
+static int run_merge(void)
+{
+	int ret;
+	struct argv_array args = ARGV_ARRAY_INIT;
+
+	argv_array_pushl(&args, "merge", NULL);
+	argv_array_push(&args, "FETCH_HEAD");
+	ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
+	argv_array_clear(&args);
+	return ret;
+}
+
 int cmd_pull(int argc, const char **argv, const char *prefix)
 {
+	const char *repo, **refspecs;
+
 	if (!getenv("_GIT_USE_BUILTIN_PULL")) {
 		const char *path = mkpath("%s/git-pull", git_exec_path());
 
@@ -29,5 +84,10 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 
 	argc = parse_options(argc, argv, prefix, pull_options, pull_usage, 0);
 
-	return 0;
+	parse_repo_refspecs(argc, argv, &repo, &refspecs);
+
+	if (run_fetch(repo, refspecs))
+		return 1;
+
+	return run_merge();
 }
-- 
2.1.4

[PATCH v3 06/19] pull: pass verbosity, --progress flags to fetch and merge

[Paul Tan]

7f87aff (Teach/Fix pull/fetch -q/-v options, 2008-11-15) taught git-pull
to accept the verbosity -v and -q options and pass them to git-fetch and
git-merge.

Re-implement support for the verbosity flags by adding it to the options
list and introducing argv_push_verbosity() to push the flags into the
argv array used to execute git-fetch and git-merge.

9839018 (fetch and pull: learn --progress, 2010-02-24) and bebd2fd
(pull: propagate --progress to merge, 2011-02-20) taught git-pull to
accept the --progress option and pass it to git-fetch and git-merge.

Use OPT_PASSTHRU() implemented earlier to pass the "--[no-]progress"
command line options to git-fetch and git-merge.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v3
    
    * Re-worded commit message.

 builtin/pull.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/builtin/pull.c b/builtin/pull.c
index 9157536..5d9f2b5 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -16,11 +16,35 @@ static const char * const pull_usage[] = {
 	NULL
 };
 
+/* Shared options */
+static int opt_verbosity;
+static char *opt_progress;
+
 static struct option pull_options[] = {
+	/* Shared options */
+	OPT__VERBOSITY(&opt_verbosity),
+	OPT_PASSTHRU(0, "progress", &opt_progress, NULL,
+		N_("force progress reporting"),
+		PARSE_OPT_NOARG),
+
 	OPT_END()
 };
 
 /**
+ * Pushes "-q" or "-v" switches into arr to match the opt_verbosity level.
+ */
+static void argv_push_verbosity(struct argv_array *arr)
+{
+	int verbosity;
+
+	for (verbosity = opt_verbosity; verbosity > 0; verbosity--)
+		argv_array_push(arr, "-v");
+
+	for (verbosity = opt_verbosity; verbosity < 0; verbosity++)
+		argv_array_push(arr, "-q");
+}
+
+/**
  * Parses argv into [<repo> [<refspecs>...]], returning their values in `repo`
  * as a string and `refspecs` as a null-terminated array of strings. If `repo`
  * is not provided in argv, it is set to NULL.
@@ -46,6 +70,12 @@ static int run_fetch(const char *repo, const char **refspecs)
 	int ret;
 
 	argv_array_pushl(&args, "fetch", "--update-head-ok", NULL);
+
+	/* Shared options */
+	argv_push_verbosity(&args);
+	if (opt_progress)
+		argv_array_push(&args, opt_progress);
+
 	if (repo) {
 		argv_array_push(&args, repo);
 		argv_array_pushv(&args, refspecs);
@@ -65,6 +95,12 @@ static int run_merge(void)
 	struct argv_array args = ARGV_ARRAY_INIT;
 
 	argv_array_pushl(&args, "merge", NULL);
+
+	/* Shared options */
+	argv_push_verbosity(&args);
+	if (opt_progress)
+		argv_array_push(&args, opt_progress);
+
 	argv_array_push(&args, "FETCH_HEAD");
 	ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
 	argv_array_clear(&args);
-- 
2.1.4

[PATCH v3 07/19] pull: pass git-merge's options to git-merge

[Paul Tan]

Specify git-merge's options in the option list, and pass any specified
options to git-merge.

These options are:

* -n, --stat, --summary: since d8abe14 (merge, pull: introduce
  '--(no-)stat' option, 2008-04-06)

* --log: since efb779f (merge, pull: add '--(no-)log' command line
  option, 2008-04-06)

* --squash: since 7d0c688 (git-merge --squash, 2006-06-23)

* --commit: since 5072a32 (Teach git-pull about --[no-]ff, --no-squash
  and --commit, 2007-10-29)

* --edit: since 8580830 ("git pull" doesn't know "--edit", 2012-02-11)

* --ff, --ff-only: since 5072a32 (Teach git-pull about --[no-]ff,
  --no-squash and --commit, 2007-10-29)

* --verify-signatures: since efed002 (merge/pull: verify GPG signatures
  of commits being merged, 2013-03-31)

* -s, --strategy: since 60fb5b2 (Use git-merge in git-pull (second
  try)., 2005-09-25)

* -X, --strategy-option: since ee2c795 (Teach git-pull to pass
  -X<option> to git-merge, 2009-11-25)

* -S, --gpg-sign: since ea230d8 (pull: add the --gpg-sign option.,
  2014-02-10)

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/pull.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/builtin/pull.c b/builtin/pull.c
index 5d9f2b5..0442da9 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -20,6 +20,18 @@ static const char * const pull_usage[] = {
 static int opt_verbosity;
 static char *opt_progress;
 
+/* Options passed to git-merge */
+static char *opt_diffstat;
+static char *opt_log;
+static char *opt_squash;
+static char *opt_commit;
+static char *opt_edit;
+static char *opt_ff;
+static char *opt_verify_signatures;
+static struct argv_array opt_strategies = ARGV_ARRAY_INIT;
+static struct argv_array opt_strategy_opts = ARGV_ARRAY_INIT;
+static char *opt_gpg_sign;
+
 static struct option pull_options[] = {
 	/* Shared options */
 	OPT__VERBOSITY(&opt_verbosity),
@@ -27,6 +39,49 @@ static struct option pull_options[] = {
 		N_("force progress reporting"),
 		PARSE_OPT_NOARG),
 
+	/* Options passed to git-merge */
+	OPT_GROUP(N_("Options related to merging")),
+	OPT_PASSTHRU('n', NULL, &opt_diffstat, NULL,
+		N_("do not show a diffstat at the end of the merge"),
+		PARSE_OPT_NOARG | PARSE_OPT_NONEG),
+	OPT_PASSTHRU(0, "stat", &opt_diffstat, NULL,
+		N_("show a diffstat at the end of the merge"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU(0, "summary", &opt_diffstat, NULL,
+		N_("(synonym to --stat)"),
+		PARSE_OPT_NOARG | PARSE_OPT_HIDDEN),
+	OPT_PASSTHRU(0, "log", &opt_log, N_("n"),
+		N_("add (at most <n>) entries from shortlog to merge commit message"),
+		PARSE_OPT_OPTARG),
+	OPT_PASSTHRU(0, "squash", &opt_squash, NULL,
+		N_("create a single commit instead of doing a merge"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU(0, "commit", &opt_commit, NULL,
+		N_("perform a commit if the merge succeeds (default)"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU(0, "edit", &opt_edit, NULL,
+		N_("edit message before committing"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU(0, "ff", &opt_ff, NULL,
+		N_("allow fast-forward"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU(0, "ff-only", &opt_ff, NULL,
+		N_("abort if fast-forward is not possible"),
+		PARSE_OPT_NOARG | PARSE_OPT_NONEG),
+	OPT_PASSTHRU(0, "verify-signatures", &opt_verify_signatures, NULL,
+		N_("verify that the named commit has a valid GPG signature"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU_ARGV('s', "strategy", &opt_strategies, N_("strategy"),
+		N_("merge strategy to use"),
+		0),
+	OPT_PASSTHRU_ARGV('X', "strategy-option", &opt_strategy_opts,
+		N_("option=value"),
+		N_("option for selected merge strategy"),
+		0),
+	OPT_PASSTHRU('S', "gpg-sign", &opt_gpg_sign, N_("key-id"),
+		N_("GPG sign commit"),
+		PARSE_OPT_OPTARG),
+
 	OPT_END()
 };
 
@@ -101,6 +156,26 @@ static int run_merge(void)
 	if (opt_progress)
 		argv_array_push(&args, opt_progress);
 
+	/* Options passed to git-merge */
+	if (opt_diffstat)
+		argv_array_push(&args, opt_diffstat);
+	if (opt_log)
+		argv_array_push(&args, opt_log);
+	if (opt_squash)
+		argv_array_push(&args, opt_squash);
+	if (opt_commit)
+		argv_array_push(&args, opt_commit);
+	if (opt_edit)
+		argv_array_push(&args, opt_edit);
+	if (opt_ff)
+		argv_array_push(&args, opt_ff);
+	if (opt_verify_signatures)
+		argv_array_push(&args, opt_verify_signatures);
+	argv_array_pushv(&args, opt_strategies.argv);
+	argv_array_pushv(&args, opt_strategy_opts.argv);
+	if (opt_gpg_sign)
+		argv_array_push(&args, opt_gpg_sign);
+
 	argv_array_push(&args, "FETCH_HEAD");
 	ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
 	argv_array_clear(&args);
-- 
2.1.4

[PATCH v3 08/19] pull: pass git-fetch's options to git-fetch

[Paul Tan]

Since eb2a8d9 (pull: handle git-fetch's options as well, 2015-06-02),
git-pull knows about and handles git-fetch's options, passing them to
git-fetch. Re-implement this behavior.

Since 29609e6 (pull: do nothing on --dry-run, 2010-05-25) git-pull
supported the --dry-run option, exiting after git-fetch if --dry-run is
set. Re-implement this behavior.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/pull.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)

diff --git a/builtin/pull.c b/builtin/pull.c
index 0442da9..731e2a6 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -32,6 +32,21 @@ static struct argv_array opt_strategies = ARGV_ARRAY_INIT;
 static struct argv_array opt_strategy_opts = ARGV_ARRAY_INIT;
 static char *opt_gpg_sign;
 
+/* Options passed to git-fetch */
+static char *opt_all;
+static char *opt_append;
+static char *opt_upload_pack;
+static int opt_force;
+static char *opt_tags;
+static char *opt_prune;
+static char *opt_recurse_submodules;
+static int opt_dry_run;
+static char *opt_keep;
+static char *opt_depth;
+static char *opt_unshallow;
+static char *opt_update_shallow;
+static char *opt_refmap;
+
 static struct option pull_options[] = {
 	/* Shared options */
 	OPT__VERBOSITY(&opt_verbosity),
@@ -82,6 +97,46 @@ static struct option pull_options[] = {
 		N_("GPG sign commit"),
 		PARSE_OPT_OPTARG),
 
+	/* Options passed to git-fetch */
+	OPT_GROUP(N_("Options related to fetching")),
+	OPT_PASSTHRU(0, "all", &opt_all, 0,
+		N_("fetch from all remotes"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU('a', "append", &opt_append, 0,
+		N_("append to .git/FETCH_HEAD instead of overwriting"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU(0, "upload-pack", &opt_upload_pack, N_("path"),
+		N_("path to upload pack on remote end"),
+		0),
+	OPT__FORCE(&opt_force, N_("force overwrite of local branch")),
+	OPT_PASSTHRU('t', "tags", &opt_tags, 0,
+		N_("fetch all tags and associated objects"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU('p', "prune", &opt_prune, 0,
+		N_("prune remote-tracking branches no longer on remote"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU(0, "recurse-submodules", &opt_recurse_submodules,
+		N_("on-demand"),
+		N_("control recursive fetching of submodules"),
+		PARSE_OPT_OPTARG),
+	OPT_BOOL(0, "dry-run", &opt_dry_run,
+		N_("dry run")),
+	OPT_PASSTHRU('k', "keep", &opt_keep, 0,
+		N_("keep downloaded pack"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU(0, "depth", &opt_depth, N_("depth"),
+		N_("deepen history of shallow clone"),
+		0),
+	OPT_PASSTHRU(0, "unshallow", &opt_unshallow, 0,
+		N_("convert to a complete repository"),
+		PARSE_OPT_NONEG | PARSE_OPT_NOARG),
+	OPT_PASSTHRU(0, "update-shallow", &opt_update_shallow, 0,
+		N_("accept refs that update .git/shallow"),
+		PARSE_OPT_NOARG),
+	OPT_PASSTHRU(0, "refmap", &opt_refmap, N_("refmap"),
+		N_("specify fetch refmap"),
+		PARSE_OPT_NONEG),
+
 	OPT_END()
 };
 
@@ -100,6 +155,16 @@ static void argv_push_verbosity(struct argv_array *arr)
 }
 
 /**
+ * Pushes "-f" switches into arr to match the opt_force level.
+ */
+static void argv_push_force(struct argv_array *arr)
+{
+	int force = opt_force;
+	while (force-- > 0)
+		argv_array_push(arr, "-f");
+}
+
+/**
  * Parses argv into [<repo> [<refspecs>...]], returning their values in `repo`
  * as a string and `refspecs` as a null-terminated array of strings. If `repo`
  * is not provided in argv, it is set to NULL.
@@ -131,6 +196,33 @@ static int run_fetch(const char *repo, const char **refspecs)
 	if (opt_progress)
 		argv_array_push(&args, opt_progress);
 
+	/* Options passed to git-fetch */
+	if (opt_all)
+		argv_array_push(&args, opt_all);
+	if (opt_append)
+		argv_array_push(&args, opt_append);
+	if (opt_upload_pack)
+		argv_array_push(&args, opt_upload_pack);
+	argv_push_force(&args);
+	if (opt_tags)
+		argv_array_push(&args, opt_tags);
+	if (opt_prune)
+		argv_array_push(&args, opt_prune);
+	if (opt_recurse_submodules)
+		argv_array_push(&args, opt_recurse_submodules);
+	if (opt_dry_run)
+		argv_array_push(&args, "--dry-run");
+	if (opt_keep)
+		argv_array_push(&args, opt_keep);
+	if (opt_depth)
+		argv_array_push(&args, opt_depth);
+	if (opt_unshallow)
+		argv_array_push(&args, opt_unshallow);
+	if (opt_update_shallow)
+		argv_array_push(&args, opt_update_shallow);
+	if (opt_refmap)
+		argv_array_push(&args, opt_refmap);
+
 	if (repo) {
 		argv_array_push(&args, repo);
 		argv_array_pushv(&args, refspecs);
@@ -200,5 +292,8 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 	if (run_fetch(repo, refspecs))
 		return 1;
 
+	if (opt_dry_run)
+		return 0;
+
 	return run_merge();
 }
-- 
2.1.4

[PATCH v3 09/19] pull: error on no merge candidates

[Paul Tan]

Commit a8c9bef (pull: improve advice for unconfigured error case,
2009-10-05) fully established the current advices given by git-pull for
the different cases where git-fetch will not have anything marked for
merge:

1. We fetched from a specific remote, and a refspec was given, but it
   ended up not fetching anything. This is usually because the user
   provided a wildcard refspec which had no matches on the remote end.

2. We fetched from a non-default remote, but didn't specify a branch to
   merge. We can't use the configured one because it applies to the
   default remote, and thus the user must specify the branches to merge.

3. We fetched from the branch's or repo's default remote, but:

   a. We are not on a branch, so there will never be a configured branch
      to merge with.

   b. We are on a branch, but there is no configured branch to merge
      with.

4. We fetched from the branch's or repo's default remote, but the
   configured branch to merge didn't get fetched (either it doesn't
   exist, or wasn't part of the configured fetch refspec)

Re-implement the above behavior by implementing get_merge_heads() to
parse the heads in FETCH_HEAD for merging, and implementing
die_no_merge_candidates(), which will be called when FETCH_HEAD has no
heads for merging.

Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v3
    
    * Tightening up of FETCH_HEAD parsing code and style fixes.

 builtin/pull.c | 113 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)

diff --git a/builtin/pull.c b/builtin/pull.c
index 731e2a6..83691fc 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -10,6 +10,8 @@
 #include "parse-options.h"
 #include "exec_cmd.h"
 #include "run-command.h"
+#include "sha1-array.h"
+#include "remote.h"
 
 static const char * const pull_usage[] = {
 	N_("git pull [options] [<repository> [<refspec>...]]"),
@@ -165,6 +167,111 @@ static void argv_push_force(struct argv_array *arr)
 }
 
 /**
+ * Appends merge candidates from FETCH_HEAD that are not marked not-for-merge
+ * into merge_heads.
+ */
+static void get_merge_heads(struct sha1_array *merge_heads)
+{
+	const char *filename = git_path("FETCH_HEAD");
+	FILE *fp;
+	struct strbuf sb = STRBUF_INIT;
+	unsigned char sha1[GIT_SHA1_RAWSZ];
+
+	if (!(fp = fopen(filename, "r")))
+		die_errno(_("could not open '%s' for reading"), filename);
+	while (strbuf_getline(&sb, fp, '\n') != EOF) {
+		if (get_sha1_hex(sb.buf, sha1))
+			continue;  /* invalid line: does not start with SHA1 */
+		if (starts_with(sb.buf + GIT_SHA1_HEXSZ, "\tnot-for-merge\t"))
+			continue;  /* ref is not-for-merge */
+		sha1_array_append(merge_heads, sha1);
+	}
+	fclose(fp);
+	strbuf_release(&sb);
+}
+
+/**
+ * Used by die_no_merge_candidates() as a for_each_remote() callback to
+ * retrieve the name of the remote if the repository only has one remote.
+ */
+static int get_only_remote(struct remote *remote, void *cb_data)
+{
+	const char **remote_name = cb_data;
+
+	if (*remote_name)
+		return -1;
+
+	*remote_name = remote->name;
+	return 0;
+}
+
+/**
+ * Dies with the appropriate reason for why there are no merge candidates:
+ *
+ * 1. We fetched from a specific remote, and a refspec was given, but it ended
+ *    up not fetching anything. This is usually because the user provided a
+ *    wildcard refspec which had no matches on the remote end.
+ *
+ * 2. We fetched from a non-default remote, but didn't specify a branch to
+ *    merge. We can't use the configured one because it applies to the default
+ *    remote, thus the user must specify the branches to merge.
+ *
+ * 3. We fetched from the branch's or repo's default remote, but:
+ *
+ *    a. We are not on a branch, so there will never be a configured branch to
+ *       merge with.
+ *
+ *    b. We are on a branch, but there is no configured branch to merge with.
+ *
+ * 4. We fetched from the branch's or repo's default remote, but the configured
+ *    branch to merge didn't get fetched. (Either it doesn't exist, or wasn't
+ *    part of the configured fetch refspec.)
+ */
+static void NORETURN die_no_merge_candidates(const char *repo, const char **refspecs)
+{
+	struct branch *curr_branch = branch_get("HEAD");
+	const char *remote = curr_branch ? curr_branch->remote_name : NULL;
+
+	if (*refspecs) {
+		fprintf_ln(stderr, _("There are no candidates for merging among the refs that you just fetched."));
+		fprintf_ln(stderr, _("Generally this means that you provided a wildcard refspec which had no\n"
+					"matches on the remote end."));
+	} else if (repo && curr_branch && (!remote || strcmp(repo, remote))) {
+		fprintf_ln(stderr, _("You asked to pull from the remote '%s', but did not specify\n"
+			"a branch. Because this is not the default configured remote\n"
+			"for your current branch, you must specify a branch on the command line."),
+			repo);
+	} else if (!curr_branch) {
+		fprintf_ln(stderr, _("You are not currently on a branch."));
+		fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
+		fprintf_ln(stderr, _("See git-pull(1) for details."));
+		fprintf(stderr, "\n");
+		fprintf_ln(stderr, "    git pull <remote> <branch>");
+		fprintf(stderr, "\n");
+	} else if (!curr_branch->merge_nr) {
+		const char *remote_name = NULL;
+
+		if (for_each_remote(get_only_remote, &remote_name) || !remote_name)
+			remote_name = "<remote>";
+
+		fprintf_ln(stderr, _("There is no tracking information for the current branch."));
+		fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
+		fprintf_ln(stderr, _("See git-pull(1) for details."));
+		fprintf(stderr, "\n");
+		fprintf_ln(stderr, "    git pull <remote> <branch>");
+		fprintf(stderr, "\n");
+		fprintf_ln(stderr, _("If you wish to set tracking information for this branch you can do so with:\n"
+				"\n"
+				"    git branch --set-upstream-to=%s/<branch> %s\n"),
+				remote_name, curr_branch->name);
+	} else
+		fprintf_ln(stderr, _("Your configuration specifies to merge with the ref '%s'\n"
+			"from the remote, but no such ref was fetched."),
+			*curr_branch->merge_name);
+	exit(1);
+}
+
+/**
  * Parses argv into [<repo> [<refspecs>...]], returning their values in `repo`
  * as a string and `refspecs` as a null-terminated array of strings. If `repo`
  * is not provided in argv, it is set to NULL.
@@ -277,6 +384,7 @@ static int run_merge(void)
 int cmd_pull(int argc, const char **argv, const char *prefix)
 {
 	const char *repo, **refspecs;
+	struct sha1_array merge_heads = SHA1_ARRAY_INIT;
 
 	if (!getenv("_GIT_USE_BUILTIN_PULL")) {
 		const char *path = mkpath("%s/git-pull", git_exec_path());
@@ -295,5 +403,10 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 	if (opt_dry_run)
 		return 0;
 
+	get_merge_heads(&merge_heads);
+
+	if (!merge_heads.nr)
+		die_no_merge_candidates(repo, refspecs);
+
 	return run_merge();
 }
-- 
2.1.4

[PATCH v3 10/19] pull: support pull.ff config

[Paul Tan]

Since b814da8 (pull: add pull.ff configuration, 2014-01-15), git-pull.sh
would lookup the configuration value of "pull.ff", and set the flag
"--ff" if its value is "true", "--no-ff" if its value is "false" and
"--ff-only" if its value is "only".

Re-implement this behavior.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v3
    
    * style fixes

 builtin/pull.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/builtin/pull.c b/builtin/pull.c
index 83691fc..0ddb964 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -167,6 +167,32 @@ static void argv_push_force(struct argv_array *arr)
 }
 
 /**
+ * If pull.ff is unset, returns NULL. If pull.ff is "true", returns "--ff". If
+ * pull.ff is "false", returns "--no-ff". If pull.ff is "only", returns
+ * "--ff-only". Otherwise, if pull.ff is set to an invalid value, die with an
+ * error.
+ */
+static const char *config_get_ff(void)
+{
+	const char *value;
+
+	if (git_config_get_value("pull.ff", &value))
+		return NULL;
+
+	switch (git_config_maybe_bool("pull.ff", value)) {
+	case 0:
+		return "--no-ff";
+	case 1:
+		return "--ff";
+	}
+
+	if (!strcmp(value, "only"))
+		return "--ff-only";
+
+	die(_("Invalid value for pull.ff: %s"), value);
+}
+
+/**
  * Appends merge candidates from FETCH_HEAD that are not marked not-for-merge
  * into merge_heads.
  */
@@ -397,6 +423,9 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 
 	parse_repo_refspecs(argc, argv, &repo, &refspecs);
 
+	if (!opt_ff)
+		opt_ff = xstrdup_or_null(config_get_ff());
+
 	if (run_fetch(repo, refspecs))
 		return 1;
 
-- 
2.1.4

[PATCH v3 11/19] pull: check if in unresolved merge state

[Paul Tan]

Since d38a30d (Be more user-friendly when refusing to do something
because of conflict., 2010-01-12), git-pull will error out with
user-friendly advices if the user is in the middle of a merge or has
unmerged files.

Re-implement this behavior. While the "has unmerged files" case can be
handled by die_resolve_conflict(), we introduce a new function
die_conclude_merge() for printing a different error message for when
there are no unmerged files but the merge has not been finished.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 advice.c       | 8 ++++++++
 advice.h       | 1 +
 builtin/pull.c | 9 +++++++++
 3 files changed, 18 insertions(+)

diff --git a/advice.c b/advice.c
index 575bec2..4965686 100644
--- a/advice.c
+++ b/advice.c
@@ -96,6 +96,14 @@ void NORETURN die_resolve_conflict(const char *me)
 	die("Exiting because of an unresolved conflict.");
 }
 
+void NORETURN die_conclude_merge(void)
+{
+	error(_("You have not concluded your merge (MERGE_HEAD exists)."));
+	if (advice_resolve_conflict)
+		advise(_("Please, commit your changes before you can merge."));
+	die(_("Exiting because of unfinished merge."));
+}
+
 void detach_advice(const char *new_name)
 {
 	const char fmt[] =
diff --git a/advice.h b/advice.h
index 5ecc6c1..b341a55 100644
--- a/advice.h
+++ b/advice.h
@@ -24,6 +24,7 @@ __attribute__((format (printf, 1, 2)))
 void advise(const char *advice, ...);
 int error_resolve_conflict(const char *me);
 extern void NORETURN die_resolve_conflict(const char *me);
+void NORETURN die_conclude_merge(void);
 void detach_advice(const char *new_name);
 
 #endif /* ADVICE_H */
diff --git a/builtin/pull.c b/builtin/pull.c
index 0ddb964..cb5898a 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -12,6 +12,7 @@
 #include "run-command.h"
 #include "sha1-array.h"
 #include "remote.h"
+#include "dir.h"
 
 static const char * const pull_usage[] = {
 	N_("git pull [options] [<repository> [<refspec>...]]"),
@@ -426,6 +427,14 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 	if (!opt_ff)
 		opt_ff = xstrdup_or_null(config_get_ff());
 
+	git_config(git_default_config, NULL);
+
+	if (read_cache_unmerged())
+		die_resolve_conflict("Pull");
+
+	if (file_exists(git_path("MERGE_HEAD")))
+		die_conclude_merge();
+
 	if (run_fetch(repo, refspecs))
 		return 1;
 
-- 
2.1.4

[PATCH v3 12/19] pull: fast-forward working tree if head is updated

[Paul Tan]

Since b10ac50 (Fix pulling into the same branch., 2005-08-25), git-pull,
upon detecting that git-fetch updated the current head, will
fast-forward the working tree to the updated head commit.

Re-implement this behavior.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/pull.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/builtin/pull.c b/builtin/pull.c
index cb5898a..0e48a14 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -412,6 +412,7 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 {
 	const char *repo, **refspecs;
 	struct sha1_array merge_heads = SHA1_ARRAY_INIT;
+	unsigned char orig_head[GIT_SHA1_RAWSZ], curr_head[GIT_SHA1_RAWSZ];
 
 	if (!getenv("_GIT_USE_BUILTIN_PULL")) {
 		const char *path = mkpath("%s/git-pull", git_exec_path());
@@ -435,12 +436,41 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 	if (file_exists(git_path("MERGE_HEAD")))
 		die_conclude_merge();
 
+	if (get_sha1("HEAD", orig_head))
+		hashclr(orig_head);
+
 	if (run_fetch(repo, refspecs))
 		return 1;
 
 	if (opt_dry_run)
 		return 0;
 
+	if (get_sha1("HEAD", curr_head))
+		hashclr(curr_head);
+
+	if (!is_null_sha1(orig_head) && !is_null_sha1(curr_head) &&
+			hashcmp(orig_head, curr_head)) {
+		/*
+		 * The fetch involved updating the current branch.
+		 *
+		 * The working tree and the index file are still based on
+		 * orig_head commit, but we are merging into curr_head.
+		 * Update the working tree to match curr_head.
+		 */
+
+		warning(_("fetch updated the current branch head.\n"
+			"fast-forwarding your working tree from\n"
+			"commit %s."), sha1_to_hex(orig_head));
+
+		if (checkout_fast_forward(orig_head, curr_head, 0))
+			die(_("Cannot fast-forward your working tree.\n"
+				"After making sure that you saved anything precious from\n"
+				"$ git diff %s\n"
+				"output, run\n"
+				"$ git reset --hard\n"
+				"to recover."), sha1_to_hex(orig_head));
+	}
+
 	get_merge_heads(&merge_heads);
 
 	if (!merge_heads.nr)
-- 
2.1.4

[PATCH v3 13/19] pull: implement pulling into an unborn branch

[Paul Tan]

b4dc085 (pull: merge into unborn by fast-forwarding from empty
tree, 2013-06-20) established git-pull's current behavior of pulling
into an unborn branch by fast-forwarding the work tree from an empty
tree to the merge head, then setting HEAD to the merge head.

Re-implement this behavior by introducing pull_into_void() which will be
called instead of run_merge() if HEAD is invalid.

Helped-by: Stephen Robin <stephen.robin@gmail.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v3
    
    * style fixes

 builtin/pull.c | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/builtin/pull.c b/builtin/pull.c
index 0e48a14..a2dd0ba 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -13,6 +13,7 @@
 #include "sha1-array.h"
 #include "remote.h"
 #include "dir.h"
+#include "refs.h"
 
 static const char * const pull_usage[] = {
 	N_("git pull [options] [<repository> [<refspec>...]]"),
@@ -368,6 +369,27 @@ static int run_fetch(const char *repo, const char **refspecs)
 }
 
 /**
+ * "Pulls into void" by branching off merge_head.
+ */
+static int pull_into_void(const unsigned char *merge_head,
+		const unsigned char *curr_head)
+{
+	/*
+	 * Two-way merge: we treat the index as based on an empty tree,
+	 * and try to fast-forward to HEAD. This ensures we will not lose
+	 * index/worktree changes that the user already made on the unborn
+	 * branch.
+	 */
+	if (checkout_fast_forward(EMPTY_TREE_SHA1_BIN, merge_head, 0))
+		return 1;
+
+	if (update_ref("initial pull", "HEAD", merge_head, curr_head, 0, UPDATE_REFS_DIE_ON_ERR))
+		return 1;
+
+	return 0;
+}
+
+/**
  * Runs git-merge, returning its exit status.
  */
 static int run_merge(void)
@@ -476,5 +498,10 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 	if (!merge_heads.nr)
 		die_no_merge_candidates(repo, refspecs);
 
-	return run_merge();
+	if (is_null_sha1(orig_head)) {
+		if (merge_heads.nr > 1)
+			die(_("Cannot merge multiple branches into empty head."));
+		return pull_into_void(*merge_heads.sha1, curr_head);
+	} else
+		return run_merge();
 }
-- 
2.1.4

[PATCH v3 14/19] pull: set reflog message

[Paul Tan]

f947413 (Use GIT_REFLOG_ACTION environment variable instead.,
2006-12-28) established git-pull's method for setting the reflog
message, which is to set the environment variable GIT_REFLOG_ACTION to
the evaluation of "pull${1+ $*}" if it has not already been set.

Re-implement this behavior.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/pull.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/builtin/pull.c b/builtin/pull.c
index a2dd0ba..a2c900e 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -169,6 +169,25 @@ static void argv_push_force(struct argv_array *arr)
 }
 
 /**
+ * Sets the GIT_REFLOG_ACTION environment variable to the concatenation of argv
+ */
+static void set_reflog_message(int argc, const char **argv)
+{
+	int i;
+	struct strbuf msg = STRBUF_INIT;
+
+	for (i = 0; i < argc; i++) {
+		if (i)
+			strbuf_addch(&msg, ' ');
+		strbuf_addstr(&msg, argv[i]);
+	}
+
+	setenv("GIT_REFLOG_ACTION", msg.buf, 0);
+
+	strbuf_release(&msg);
+}
+
+/**
  * If pull.ff is unset, returns NULL. If pull.ff is "true", returns "--ff". If
  * pull.ff is "false", returns "--no-ff". If pull.ff is "only", returns
  * "--ff-only". Otherwise, if pull.ff is set to an invalid value, die with an
@@ -443,6 +462,9 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 			die_errno("could not exec %s", path);
 	}
 
+	if (!getenv("GIT_REFLOG_ACTION"))
+		set_reflog_message(argc, argv);
+
 	argc = parse_options(argc, argv, prefix, pull_options, pull_usage, 0);
 
 	parse_repo_refspecs(argc, argv, &repo, &refspecs);
-- 
2.1.4

[PATCH v3 15/19] pull: teach git pull about --rebase

[Paul Tan]

Since cd67e4d (Teach 'git pull' about --rebase, 2007-11-28), if the
--rebase option is set, git-rebase is run instead of git-merge.

Re-implement this by introducing run_rebase(), which is called instead
of run_merge() if opt_rebase is a true value.

Since c85c792 (pull --rebase: be cleverer with rebased upstream
branches, 2008-01-26), git-pull handles the case where the upstream
branch was rebased since it was last fetched. The fork point (old remote
ref) of the branch from the upstream branch is calculated before fetch,
and then rebased from onto the new remote head (merge_head) after fetch.

Re-implement this by introducing get_merge_branch_2() and
get_merge_branch_1() to find the upstream branch for the
specified/current branch, and get_rebase_fork_point() which will find
the fork point between the upstream branch and current branch.

However, the above change created a problem where git-rebase cannot
detect commits that are already upstream, and thus may result in
unnecessary conflicts. cf65426 (pull --rebase: Avoid spurious conflicts
and reapplying unnecessary patches, 2010-08-12) fixes this by ignoring
the above old remote ref if it is contained within the merge base of the
merge head and the current branch.

This is re-implemented in run_rebase() where fork_point is not used if
it is the merge base returned by get_octopus_merge_base().

Helped-by: Stefan Beller <sbeller@google.com>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v3
    
    * use branch_get_upstream()
    
    * style fixes
    
    * adjust to removal of branch->remote in 9e3751d (remote.c: drop
      "remote" pointer from "struct branch", 2015-05-21)
    
    * I realised that if parse_config_rebase() handled the die()-ing and
      error()-ing, it would make the next patch more pleasant.

 builtin/pull.c | 247 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 245 insertions(+), 2 deletions(-)

diff --git a/builtin/pull.c b/builtin/pull.c
index a2c900e..8915947 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -15,6 +15,53 @@
 #include "dir.h"
 #include "refs.h"
 
+enum rebase_type {
+	REBASE_INVALID = -1,
+	REBASE_FALSE = 0,
+	REBASE_TRUE,
+	REBASE_PRESERVE
+};
+
+/**
+ * Parses the value of --rebase. If value is a false value, returns
+ * REBASE_FALSE. If value is a true value, returns REBASE_TRUE. If value is
+ * "preserve", returns REBASE_PRESERVE. If value is a invalid value, dies with
+ * a fatal error if fatal is true, otherwise returns REBASE_INVALID.
+ */
+static enum rebase_type parse_config_rebase(const char *key, const char *value,
+		int fatal)
+{
+	int v = git_config_maybe_bool("pull.rebase", value);
+
+	if (!v)
+		return REBASE_FALSE;
+	else if (v > 0)
+		return REBASE_TRUE;
+	else if (!strcmp(value, "preserve"))
+		return REBASE_PRESERVE;
+
+	if (fatal)
+		die(_("Invalid value for %s: %s"), key, value);
+	else
+		error(_("Invalid value for %s: %s"), key, value);
+
+	return REBASE_INVALID;
+}
+
+/**
+ * Callback for --rebase, which parses arg with parse_config_rebase().
+ */
+static int parse_opt_rebase(const struct option *opt, const char *arg, int unset)
+{
+	enum rebase_type *value = opt->value;
+
+	if (arg)
+		*value = parse_config_rebase("--rebase", arg, 0);
+	else
+		*value = unset ? REBASE_FALSE : REBASE_TRUE;
+	return *value == REBASE_INVALID ? -1 : 0;
+}
+
 static const char * const pull_usage[] = {
 	N_("git pull [options] [<repository> [<refspec>...]]"),
 	NULL
@@ -24,7 +71,8 @@ static const char * const pull_usage[] = {
 static int opt_verbosity;
 static char *opt_progress;
 
-/* Options passed to git-merge */
+/* Options passed to git-merge or git-rebase */
+static enum rebase_type opt_rebase;
 static char *opt_diffstat;
 static char *opt_log;
 static char *opt_squash;
@@ -58,8 +106,12 @@ static struct option pull_options[] = {
 		N_("force progress reporting"),
 		PARSE_OPT_NOARG),
 
-	/* Options passed to git-merge */
+	/* Options passed to git-merge or git-rebase */
 	OPT_GROUP(N_("Options related to merging")),
+	{ OPTION_CALLBACK, 'r', "rebase", &opt_rebase,
+	  N_("false|true|preserve"),
+	  N_("incorporate changes by rebasing rather than merging"),
+	  PARSE_OPT_OPTARG, parse_opt_rebase },
 	OPT_PASSTHRU('n', NULL, &opt_diffstat, NULL,
 		N_("do not show a diffstat at the end of the merge"),
 		PARSE_OPT_NOARG | PARSE_OPT_NONEG),
@@ -449,11 +501,194 @@ static int run_merge(void)
 	return ret;
 }
 
+/**
+ * Returns remote's upstream branch for the current branch. If remote is NULL,
+ * the current branch's configured default remote is used. Returns NULL if
+ * `remote` does not name a valid remote, HEAD does not point to a branch,
+ * remote is not the branch's configured remote or the branch does not have any
+ * configured upstream branch.
+ */
+static const char *get_upstream_branch(const char *remote)
+{
+	struct remote *rm;
+	struct branch *curr_branch;
+	const char *curr_branch_remote;
+
+	rm = remote_get(remote);
+	if (!rm)
+		return NULL;
+
+	curr_branch = branch_get("HEAD");
+	if (!curr_branch)
+		return NULL;
+
+	curr_branch_remote = remote_for_branch(curr_branch, NULL);
+	assert(curr_branch_remote);
+
+	if (strcmp(curr_branch_remote, rm->name))
+		return NULL;
+
+	return branch_get_upstream(curr_branch, NULL);
+}
+
+/**
+ * Derives the remote tracking branch from the remote and refspec.
+ *
+ * FIXME: The current implementation assumes the default mapping of
+ * refs/heads/<branch_name> to refs/remotes/<remote_name>/<branch_name>.
+ */
+static const char *get_tracking_branch(const char *remote, const char *refspec)
+{
+	struct refspec *spec;
+	const char *spec_src;
+	const char *merge_branch;
+
+	spec = parse_fetch_refspec(1, &refspec);
+	spec_src = spec->src;
+	if (!*spec_src || !strcmp(spec_src, "HEAD"))
+		spec_src = "HEAD";
+	else if (skip_prefix(spec_src, "heads/", &spec_src))
+		;
+	else if (skip_prefix(spec_src, "refs/heads/", &spec_src))
+		;
+	else if (starts_with(spec_src, "refs/") ||
+		starts_with(spec_src, "tags/") ||
+		starts_with(spec_src, "remotes/"))
+		spec_src = "";
+
+	if (*spec_src) {
+		if (!strcmp(remote, "."))
+			merge_branch = mkpath("refs/heads/%s", spec_src);
+		else
+			merge_branch = mkpath("refs/remotes/%s/%s", remote, spec_src);
+	} else
+		merge_branch = NULL;
+
+	free_refspec(1, spec);
+	return merge_branch;
+}
+
+/**
+ * Given the repo and refspecs, sets fork_point to the point at which the
+ * current branch forked from its remote tracking branch. Returns 0 on success,
+ * -1 on failure.
+ */
+static int get_rebase_fork_point(unsigned char *fork_point, const char *repo,
+		const char *refspec)
+{
+	int ret;
+	struct branch *curr_branch;
+	const char *remote_branch;
+	struct child_process cp = CHILD_PROCESS_INIT;
+	struct strbuf sb = STRBUF_INIT;
+
+	curr_branch = branch_get("HEAD");
+	if (!curr_branch)
+		return -1;
+
+	if (refspec)
+		remote_branch = get_tracking_branch(repo, refspec);
+	else
+		remote_branch = get_upstream_branch(repo);
+
+	if (!remote_branch)
+		return -1;
+
+	argv_array_pushl(&cp.args, "merge-base", "--fork-point",
+			remote_branch, curr_branch->name, NULL);
+	cp.no_stdin = 1;
+	cp.no_stderr = 1;
+	cp.git_cmd = 1;
+
+	ret = capture_command(&cp, &sb, GIT_SHA1_HEXSZ);
+	if (ret)
+		goto cleanup;
+
+	ret = get_sha1_hex(sb.buf, fork_point);
+	if (ret)
+		goto cleanup;
+
+cleanup:
+	strbuf_release(&sb);
+	return ret ? -1 : 0;
+}
+
+/**
+ * Sets merge_base to the octopus merge base of curr_head, merge_head and
+ * fork_point. Returns 0 if a merge base is found, 1 otherwise.
+ */
+static int get_octopus_merge_base(unsigned char *merge_base,
+		const unsigned char *curr_head,
+		const unsigned char *merge_head,
+		const unsigned char *fork_point)
+{
+	struct commit_list *revs = NULL, *result;
+
+	commit_list_insert(lookup_commit_reference(curr_head), &revs);
+	commit_list_insert(lookup_commit_reference(merge_head), &revs);
+	if (!is_null_sha1(fork_point))
+		commit_list_insert(lookup_commit_reference(fork_point), &revs);
+
+	result = reduce_heads(get_octopus_merge_bases(revs));
+	free_commit_list(revs);
+	if (!result)
+		return 1;
+
+	hashcpy(merge_base, result->item->object.sha1);
+	return 0;
+}
+
+/**
+ * Given the current HEAD SHA1, the merge head returned from git-fetch and the
+ * fork point calculated by get_rebase_fork_point(), runs git-rebase with the
+ * appropriate arguments and returns its exit status.
+ */
+static int run_rebase(const unsigned char *curr_head,
+		const unsigned char *merge_head,
+		const unsigned char *fork_point)
+{
+	int ret;
+	unsigned char oct_merge_base[GIT_SHA1_RAWSZ];
+	struct argv_array args = ARGV_ARRAY_INIT;
+
+	if (!get_octopus_merge_base(oct_merge_base, curr_head, merge_head, fork_point))
+		if (!is_null_sha1(fork_point) && !hashcmp(oct_merge_base, fork_point))
+			fork_point = NULL;
+
+	argv_array_push(&args, "rebase");
+
+	/* Shared options */
+	argv_push_verbosity(&args);
+
+	/* Options passed to git-rebase */
+	if (opt_rebase == REBASE_PRESERVE)
+		argv_array_push(&args, "--preserve-merges");
+	if (opt_diffstat)
+		argv_array_push(&args, opt_diffstat);
+	argv_array_pushv(&args, opt_strategies.argv);
+	argv_array_pushv(&args, opt_strategy_opts.argv);
+	if (opt_gpg_sign)
+		argv_array_push(&args, opt_gpg_sign);
+
+	argv_array_push(&args, "--onto");
+	argv_array_push(&args, sha1_to_hex(merge_head));
+
+	if (fork_point && !is_null_sha1(fork_point))
+		argv_array_push(&args, sha1_to_hex(fork_point));
+	else
+		argv_array_push(&args, sha1_to_hex(merge_head));
+
+	ret = run_command_v_opt(args.argv, RUN_GIT_CMD);
+	argv_array_clear(&args);
+	return ret;
+}
+
 int cmd_pull(int argc, const char **argv, const char *prefix)
 {
 	const char *repo, **refspecs;
 	struct sha1_array merge_heads = SHA1_ARRAY_INIT;
 	unsigned char orig_head[GIT_SHA1_RAWSZ], curr_head[GIT_SHA1_RAWSZ];
+	unsigned char rebase_fork_point[GIT_SHA1_RAWSZ];
 
 	if (!getenv("_GIT_USE_BUILTIN_PULL")) {
 		const char *path = mkpath("%s/git-pull", git_exec_path());
@@ -483,6 +718,10 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 	if (get_sha1("HEAD", orig_head))
 		hashclr(orig_head);
 
+	if (opt_rebase)
+		if (get_rebase_fork_point(rebase_fork_point, repo, *refspecs))
+			hashclr(rebase_fork_point);
+
 	if (run_fetch(repo, refspecs))
 		return 1;
 
@@ -524,6 +763,10 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 		if (merge_heads.nr > 1)
 			die(_("Cannot merge multiple branches into empty head."));
 		return pull_into_void(*merge_heads.sha1, curr_head);
+	} else if (opt_rebase) {
+		if (merge_heads.nr > 1)
+			die(_("Cannot rebase onto multiple branches."));
+		return run_rebase(curr_head, *merge_heads.sha1, rebase_fork_point);
 	} else
 		return run_merge();
 }
-- 
2.1.4

[PATCH v3 16/19] pull: configure --rebase via branch.<name>.rebase or pull.rebase

[Paul Tan]

Since cd67e4d (Teach 'git pull' about --rebase, 2007-11-28),
fetch+rebase could be set by default by defining the config variable
branch.<name>.rebase. This setting can be overriden on the command line
by --rebase and --no-rebase.

Since 6b37dff (pull: introduce a pull.rebase option to enable --rebase,
2011-11-06), git-pull --rebase can also be configured via the
pull.rebase configuration option.

Re-implement support for these two configuration settings by introducing
config_get_rebase() which is called before parse_options() to set the
default value of opt_rebase.

Helped-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
---

Notes:
    v3
    
    * Now that parse_config_rebase() takes care of the die()-ing and
      error()-ing, we only need one function again. Yay!
    
    * The free()s is ugly though. Ideally, I would like to have a xstrfmt()
      function that returns a static buffer.
    
    * We now don't lookup the pull.rebase config if the --rebase option is
      provided on the command-line.

 builtin/pull.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/builtin/pull.c b/builtin/pull.c
index 8915947..e4098d0 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -72,7 +72,7 @@ static int opt_verbosity;
 static char *opt_progress;
 
 /* Options passed to git-merge or git-rebase */
-static enum rebase_type opt_rebase;
+static enum rebase_type opt_rebase = -1;
 static char *opt_diffstat;
 static char *opt_log;
 static char *opt_squash;
@@ -266,6 +266,35 @@ static const char *config_get_ff(void)
 }
 
 /**
+ * Returns the default configured value for --rebase. It first looks for the
+ * value of "branch.$curr_branch.rebase", where $curr_branch is the current
+ * branch, and if HEAD is detached or the configuration key does not exist,
+ * looks for the value of "pull.rebase". If both configuration keys do not
+ * exist, returns REBASE_FALSE.
+ */
+static enum rebase_type config_get_rebase(void)
+{
+	struct branch *curr_branch = branch_get("HEAD");
+	const char *value;
+
+	if (curr_branch) {
+		char *key = xstrfmt("branch.%s.rebase", curr_branch->name);
+
+		if (!git_config_get_value(key, &value)) {
+			free(key);
+			return parse_config_rebase(key, value, 1);
+		}
+
+		free(key);
+	}
+
+	if (!git_config_get_value("pull.rebase", &value))
+		return parse_config_rebase("pull.rebase", value, 1);
+
+	return REBASE_FALSE;
+}
+
+/**
  * Appends merge candidates from FETCH_HEAD that are not marked not-for-merge
  * into merge_heads.
  */
@@ -707,6 +736,9 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 	if (!opt_ff)
 		opt_ff = xstrdup_or_null(config_get_ff());
 
+	if (opt_rebase < 0)
+		opt_rebase = config_get_rebase();
+
 	git_config(git_default_config, NULL);
 
 	if (read_cache_unmerged())
-- 
2.1.4

[PATCH v3 17/19] pull --rebase: exit early when the working directory is dirty

[Paul Tan]

Re-implement the behavior introduced by f9189cf (pull --rebase: exit
early when the working directory is dirty, 2008-05-21).

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/pull.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 76 insertions(+), 1 deletion(-)

diff --git a/builtin/pull.c b/builtin/pull.c
index e4098d0..a379c1f 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -14,6 +14,8 @@
 #include "remote.h"
 #include "dir.h"
 #include "refs.h"
+#include "revision.h"
+#include "lockfile.h"
 
 enum rebase_type {
 	REBASE_INVALID = -1,
@@ -295,6 +297,73 @@ static enum rebase_type config_get_rebase(void)
 }
 
 /**
+ * Returns 1 if there are unstaged changes, 0 otherwise.
+ */
+static int has_unstaged_changes(const char *prefix)
+{
+	struct rev_info rev_info;
+	int result;
+
+	init_revisions(&rev_info, prefix);
+	DIFF_OPT_SET(&rev_info.diffopt, IGNORE_SUBMODULES);
+	DIFF_OPT_SET(&rev_info.diffopt, QUICK);
+	diff_setup_done(&rev_info.diffopt);
+	result = run_diff_files(&rev_info, 0);
+	return diff_result_code(&rev_info.diffopt, result);
+}
+
+/**
+ * Returns 1 if there are uncommitted changes, 0 otherwise.
+ */
+static int has_uncommitted_changes(const char *prefix)
+{
+	struct rev_info rev_info;
+	int result;
+
+	if (is_cache_unborn())
+		return 0;
+
+	init_revisions(&rev_info, prefix);
+	DIFF_OPT_SET(&rev_info.diffopt, IGNORE_SUBMODULES);
+	DIFF_OPT_SET(&rev_info.diffopt, QUICK);
+	add_head_to_pending(&rev_info);
+	diff_setup_done(&rev_info.diffopt);
+	result = run_diff_index(&rev_info, 1);
+	return diff_result_code(&rev_info.diffopt, result);
+}
+
+/**
+ * If the work tree has unstaged or uncommitted changes, dies with the
+ * appropriate message.
+ */
+static void die_on_unclean_work_tree(const char *prefix)
+{
+	struct lock_file *lock_file = xcalloc(1, sizeof(*lock_file));
+	int do_die = 0;
+
+	hold_locked_index(lock_file, 0);
+	refresh_cache(REFRESH_QUIET);
+	update_index_if_able(&the_index, lock_file);
+	rollback_lock_file(lock_file);
+
+	if (has_unstaged_changes(prefix)) {
+		error(_("Cannot pull with rebase: You have unstaged changes."));
+		do_die = 1;
+	}
+
+	if (has_uncommitted_changes(prefix)) {
+		if (do_die)
+			error(_("Additionally, your index contains uncommitted changes."));
+		else
+			error(_("Cannot pull with rebase: Your index contains uncommitted changes."));
+		do_die = 1;
+	}
+
+	if (do_die)
+		exit(1);
+}
+
+/**
  * Appends merge candidates from FETCH_HEAD that are not marked not-for-merge
  * into merge_heads.
  */
@@ -750,9 +819,15 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 	if (get_sha1("HEAD", orig_head))
 		hashclr(orig_head);
 
-	if (opt_rebase)
+	if (opt_rebase) {
+		if (is_null_sha1(orig_head) && !is_cache_unborn())
+			die(_("Updating an unborn branch with changes added to the index."));
+
+		die_on_unclean_work_tree(prefix);
+
 		if (get_rebase_fork_point(rebase_fork_point, repo, *refspecs))
 			hashclr(rebase_fork_point);
+	}
 
 	if (run_fetch(repo, refspecs))
 		return 1;
-- 
2.1.4

[PATCH v3 18/19] pull --rebase: error on no merge candidate cases

[Paul Tan]

Tweak the error messages printed by die_no_merge_candidates() to take
into account that we may be "rebasing against" rather than "merging
with".

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 builtin/pull.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/builtin/pull.c b/builtin/pull.c
index a379c1f..b78c67c 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -430,7 +430,10 @@ static void NORETURN die_no_merge_candidates(const char *repo, const char **refs
 	const char *remote = curr_branch ? curr_branch->remote_name : NULL;
 
 	if (*refspecs) {
-		fprintf_ln(stderr, _("There are no candidates for merging among the refs that you just fetched."));
+		if (opt_rebase)
+			fprintf_ln(stderr, _("There is no candidate for rebasing against among the refs that you just fetched."));
+		else
+			fprintf_ln(stderr, _("There are no candidates for merging among the refs that you just fetched."));
 		fprintf_ln(stderr, _("Generally this means that you provided a wildcard refspec which had no\n"
 					"matches on the remote end."));
 	} else if (repo && curr_branch && (!remote || strcmp(repo, remote))) {
@@ -440,7 +443,10 @@ static void NORETURN die_no_merge_candidates(const char *repo, const char **refs
 			repo);
 	} else if (!curr_branch) {
 		fprintf_ln(stderr, _("You are not currently on a branch."));
-		fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
+		if (opt_rebase)
+			fprintf_ln(stderr, _("Please specify which branch you want to rebase against."));
+		else
+			fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
 		fprintf_ln(stderr, _("See git-pull(1) for details."));
 		fprintf(stderr, "\n");
 		fprintf_ln(stderr, "    git pull <remote> <branch>");
@@ -452,7 +458,10 @@ static void NORETURN die_no_merge_candidates(const char *repo, const char **refs
 			remote_name = "<remote>";
 
 		fprintf_ln(stderr, _("There is no tracking information for the current branch."));
-		fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
+		if (opt_rebase)
+			fprintf_ln(stderr, _("Please specify which branch you want to rebase against."));
+		else
+			fprintf_ln(stderr, _("Please specify which branch you want to merge with."));
 		fprintf_ln(stderr, _("See git-pull(1) for details."));
 		fprintf(stderr, "\n");
 		fprintf_ln(stderr, "    git pull <remote> <branch>");
-- 
2.1.4

[PATCH v3 19/19] pull: remove redirection to git-pull.sh

[Paul Tan]

At the beginning of the rewrite of git-pull.sh to C, we introduced a
redirection to git-pull.sh if the environment variable
_GIT_USE_BUILTIN_PULL was not defined in order to not break test scripts
that relied on a functional git-pull.

Now that all of git-pull's functionality has been re-implemented in
builtin/pull.c, remove this redirection, and retire the old git-pull.sh
into contrib/examples/.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
---
 Makefile                                    | 1 -
 builtin/pull.c                              | 7 -------
 git-pull.sh => contrib/examples/git-pull.sh | 0
 3 files changed, 8 deletions(-)
 rename git-pull.sh => contrib/examples/git-pull.sh (100%)

diff --git a/Makefile b/Makefile
index 2057a9d..67cef1c 100644
--- a/Makefile
+++ b/Makefile
@@ -474,7 +474,6 @@ SCRIPT_SH += git-merge-octopus.sh
 SCRIPT_SH += git-merge-one-file.sh
 SCRIPT_SH += git-merge-resolve.sh
 SCRIPT_SH += git-mergetool.sh
-SCRIPT_SH += git-pull.sh
 SCRIPT_SH += git-quiltimport.sh
 SCRIPT_SH += git-rebase.sh
 SCRIPT_SH += git-remote-testgit.sh
diff --git a/builtin/pull.c b/builtin/pull.c
index b78c67c..d690aee 100644
--- a/builtin/pull.c
+++ b/builtin/pull.c
@@ -797,13 +797,6 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
 	unsigned char orig_head[GIT_SHA1_RAWSZ], curr_head[GIT_SHA1_RAWSZ];
 	unsigned char rebase_fork_point[GIT_SHA1_RAWSZ];
 
-	if (!getenv("_GIT_USE_BUILTIN_PULL")) {
-		const char *path = mkpath("%s/git-pull", git_exec_path());
-
-		if (sane_execvp(path, (char **)argv) < 0)
-			die_errno("could not exec %s", path);
-	}
-
 	if (!getenv("GIT_REFLOG_ACTION"))
 		set_reflog_message(argc, argv);
 
diff --git a/git-pull.sh b/contrib/examples/git-pull.sh
similarity index 100%
rename from git-pull.sh
rename to contrib/examples/git-pull.sh
-- 
2.1.4