Merge branch 'js/branch-track'

* js/branch-track:
  doc: documentation update for the branch track changes
  branch: optionally setup branch.*.merge from upstream local branches

Conflicts:

	Documentation/config.txt
	Documentation/git-branch.txt
	Documentation/git-checkout.txt
	builtin-branch.c
	cache.h
	t/t7201-co.sh

12 files changed, 131 insertions, 73 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 8e361a1e77..4027726f2e 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -379,10 +379,14 @@ apply.whitespace::
 
 branch.autosetupmerge::
 	Tells `git-branch` and `git-checkout` to setup new branches
-	so that linkgit:git-pull[1] will appropriately merge from that
-	remote branch.  Note that even if this option is not set,
+	so that linkgit:git-pull[1] will appropriately merge from the
+	starting point branch. Note that even if this option is not set,
 	this behavior can be chosen per-branch using the `--track`
-	and `--no-track` options.  This option defaults to true.
+	and `--no-track` options. The valid settings are: `false` -- no
+	automatic setup is done; `true` -- automatic setup is done when the
+	starting point is a remote branch; `always` -- automatic setup is
+	done when the starting point is either a local branch or remote
+	branch. This option defaults to true.
 
 branch.<name>.remote::
 	When in branch <name>, it tells `git fetch` which remote to fetch.
diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index 7e8874acaa..6f07a17a2c 100644
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -35,11 +35,10 @@ working tree to it; use "git checkout <newbranch>" to switch to the
 new branch.
 
 When a local branch is started off a remote branch, git sets up the
-branch so that linkgit:git-pull[1] will appropriately merge from that
-remote branch.  If this behavior is not desired, it is possible to
-disable it using the global `branch.autosetupmerge` configuration
-flag.  That setting can be overridden by using the `--track`
-and `--no-track` options.
+branch so that linkgit:git-pull[1] will appropriately merge from
+the remote branch. This behavior may be changed via the global
+`branch.autosetupmerge` configuration flag. That setting can be
+overridden by using the `--track` and `--no-track` options.
 
 With a '-m' or '-M' option, <oldbranch> will be renamed to <newbranch>.
 If <oldbranch> had a corresponding reflog, it is renamed to match
@@ -105,20 +104,19 @@ OPTIONS
 	Display the full sha1s in output listing rather than abbreviating them.
 
 --track::
-	Set up configuration so that git-pull will automatically
-	retrieve data from the remote branch.  Use this if you always
-	pull from the same remote branch into the new branch, or if you
-	don't want to use "git pull <repository> <refspec>" explicitly.
-	This behavior is the default.  Set the
-	branch.autosetupmerge configuration variable to false if you
-	want git-checkout and git-branch to always behave as if
-	'--no-track' were given.
+	When creating a new branch, set up configuration so that git-pull
+	will automatically retrieve data from the start point, which must be
+	a branch. Use this if you always pull from the same upstream branch
+	into the new branch, and if you don't want to use "git pull
+	<repository> <refspec>" explicitly. This behavior is the default
+	when the start point is a remote branch. Set the
+	branch.autosetupmerge configuration variable to `false` if you want
+	git-checkout and git-branch to always behave as if '--no-track' were
+	given. Set it to `always` if you want this behavior when the
+	start-point is either a local or remote branch.
 
 --no-track::
-	When a branch is created off a remote branch,
-	set up configuration so that git-pull will not retrieve data
-	from the remote branch, ignoring the branch.autosetupmerge
-	configuration variable.
+	Ignore the branch.autosetupmerge configuration variable.
 
 <branchname>::
 	The name of the branch to create or delete.
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index b4cfa044bb..4014e7256d 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -48,21 +48,19 @@ OPTIONS
 	may restrict the characters allowed in a branch name.
 
 --track::
-	When -b is given and a branch is created off a remote branch,
-	set up configuration so that git-pull will automatically
-	retrieve data from the remote branch.  Use this if you always
-	pull from the same remote branch into the new branch, or if you
-	don't want to use "git pull <repository> <refspec>" explicitly.
-	This behavior is the default.  Set the
-	branch.autosetupmerge configuration variable to false if you
-	want git-checkout and git-branch to always behave as if
-	'--no-track' were given.
+	When creating a new branch, set up configuration so that git-pull
+	will automatically retrieve data from the start point, which must be
+	a branch. Use this if you always pull from the same upstream branch
+	into the new branch, and if you don't want to use "git pull
+	<repository> <refspec>" explicitly. This behavior is the default
+	when the start point is a remote branch. Set the
+	branch.autosetupmerge configuration variable to `false` if you want
+	git-checkout and git-branch to always behave as if '--no-track' were
+	given. Set it to `always` if you want this behavior when the
+	start-point is either a local or remote branch.
 
 --no-track::
-	When -b is given and a branch is created off a remote branch,
-	set up configuration so that git-pull will not retrieve data
-	from the remote branch, ignoring the branch.autosetupmerge
-	configuration variable.
+	Ignore the branch.autosetupmerge configuration variable.
 
 -l::
 	Create the new branch's reflog.  This activates recording of
diff --git a/branch.c b/branch.c
index 1fc8788897..daf862e728 100644
--- a/branch.c
+++ b/branch.c
@@ -37,7 +37,8 @@ static int find_tracked_branch(struct remote *remote, void *priv)
  * to infer the settings for branch.<new_ref>.{remote,merge} from the
  * config.
  */
-static int setup_tracking(const char *new_ref, const char *orig_ref)
+static int setup_tracking(const char *new_ref, const char *orig_ref,
+                          enum branch_track track)
 {
 	char key[1024];
 	struct tracking tracking;
@@ -48,30 +49,36 @@ static int setup_tracking(const char *new_ref, const char *orig_ref)
 
 	memset(&tracking, 0, sizeof(tracking));
 	tracking.spec.dst = (char *)orig_ref;
-	if (for_each_remote(find_tracked_branch, &tracking) ||
-			!tracking.matches)
+	if (for_each_remote(find_tracked_branch, &tracking))
 		return 1;
 
+	if (!tracking.matches)
+		switch (track) {
+		case BRANCH_TRACK_ALWAYS:
+		case BRANCH_TRACK_EXPLICIT:
+			break;
+		default:
+			return 1;
+		}
+
 	if (tracking.matches > 1)
 		return error("Not tracking: ambiguous information for ref %s",
 				orig_ref);
 
-	if (tracking.matches == 1) {
-		sprintf(key, "branch.%s.remote", new_ref);
-		git_config_set(key, tracking.remote ?  tracking.remote : ".");
-		sprintf(key, "branch.%s.merge", new_ref);
-		git_config_set(key, tracking.src);
-		free(tracking.src);
-		printf("Branch %s set up to track remote branch %s.\n",
-			       new_ref, orig_ref);
-	}
+	sprintf(key, "branch.%s.remote", new_ref);
+	git_config_set(key, tracking.remote ?  tracking.remote : ".");
+	sprintf(key, "branch.%s.merge", new_ref);
+	git_config_set(key, tracking.src ? tracking.src : orig_ref);
+	free(tracking.src);
+	printf("Branch %s set up to track %s branch %s.\n", new_ref,
+		tracking.remote ? "remote" : "local", orig_ref);
 
 	return 0;
 }
 
 void create_branch(const char *head,
 		   const char *name, const char *start_name,
-		   int force, int reflog, int track)
+		   int force, int reflog, enum branch_track track)
 {
 	struct ref_lock *lock;
 	struct commit *commit;
@@ -98,7 +105,8 @@ void create_branch(const char *head,
 	switch (dwim_ref(start_name, strlen(start_name), sha1, &real_ref)) {
 	case 0:
 		/* Not branching from any existing branch */
-		real_ref = NULL;
+		if (track == BRANCH_TRACK_EXPLICIT)
+			die("Cannot setup tracking information; starting point is not a branch.");
 		break;
 	case 1:
 		/* Unique completion -- good */
@@ -126,17 +134,13 @@ void create_branch(const char *head,
 		snprintf(msg, sizeof msg, "branch: Created from %s",
 			 start_name);
 
-	/* When branching off a remote branch, set up so that git-pull
-	   automatically merges from there.  So far, this is only done for
-	   remotes registered via .git/config.  */
 	if (real_ref && track)
-		setup_tracking(name, real_ref);
+		setup_tracking(name, real_ref, track);
 
 	if (write_ref_sha1(lock, sha1, msg) < 0)
 		die("Failed to write ref: %s.", strerror(errno));
 
-	if (real_ref)
-		free(real_ref);
+	free(real_ref);
 }
 
 void remove_branch_state(void)
diff --git a/branch.h b/branch.h
index d30abe0369..9f0c2a2c1f 100644
--- a/branch.h
+++ b/branch.h
@@ -13,7 +13,7 @@
  * branch for (if any).
  */
 void create_branch(const char *head, const char *name, const char *start_name,
-		   int force, int reflog, int track);
+		   int force, int reflog, enum branch_track track);
 
 /*
  * Remove information about the state of working on the current
diff --git a/builtin-branch.c b/builtin-branch.c
index 7e991030ca..a7844454a2 100644
--- a/builtin-branch.c
+++ b/builtin-branch.c
@@ -30,8 +30,6 @@ static const char * const builtin_branch_usage[] = {
 static const char *head;
 static unsigned char head_sha1[20];
 
-static int branch_track = 1;
-
 static int branch_use_color = -1;
 static char branch_colors[][COLOR_MAXLEN] = {
 	"\033[m",	/* reset */
@@ -76,10 +74,6 @@ static int git_branch_config(const char *var, const char *value)
 		color_parse(value, var, branch_colors[slot]);
 		return 0;
 	}
-	if (!strcmp(var, "branch.autosetupmerge")) {
-		branch_track = git_config_bool(var, value);
-		return 0;
-	}
 	return git_color_default_config(var, value);
 }
 
@@ -420,14 +414,16 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 {
 	int delete = 0, rename = 0, force_create = 0;
 	int verbose = 0, abbrev = DEFAULT_ABBREV, detached = 0;
-	int reflog = 0, track;
+	int reflog = 0;
+	enum branch_track track;
 	int kinds = REF_LOCAL_BRANCH;
 	struct commit_list *with_commit = NULL;
 
 	struct option options[] = {
 		OPT_GROUP("Generic options"),
 		OPT__VERBOSE(&verbose),
-		OPT_BOOLEAN( 0 , "track",  &track, "set up tracking mode (see git-pull(1))"),
+		OPT_SET_INT( 0 , "track",  &track, "set up tracking mode (see git-pull(1))",
+			BRANCH_TRACK_EXPLICIT),
 		OPT_BOOLEAN( 0 , "color",  &branch_use_color, "use colored output"),
 		OPT_SET_INT('r', NULL,     &kinds, "act on remote-tracking branches",
 			REF_REMOTE_BRANCH),
@@ -458,7 +454,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 	if (branch_use_color == -1)
 		branch_use_color = git_use_color_default;
 
-	track = branch_track;
+	track = git_branch_track;
 	argc = parse_options(argc, argv, options, builtin_branch_usage, 0);
 	if (!!delete + !!rename + !!force_create > 1)
 		usage_with_options(builtin_branch_usage, options);
diff --git a/builtin-checkout.c b/builtin-checkout.c
index d5f093094c..4a4bb8b77d 100644
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -186,7 +186,7 @@ struct checkout_opts {
 
 	char *new_branch;
 	int new_branch_log;
-	int track;
+	enum branch_track track;
 };
 
 struct branch_info {
@@ -480,13 +480,8 @@ static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
 	return post_checkout_hook(old.commit, new->commit, 1);
 }
 
-static int branch_track = 0;
-
 static int git_checkout_config(const char *var, const char *value)
 {
-	if (!strcmp(var, "branch.autosetupmerge"))
-		branch_track = git_config_bool(var, value);
-
 	return git_default_config(var, value);
 }
 
@@ -501,7 +496,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		OPT__QUIET(&opts.quiet),
 		OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
 		OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
-		OPT_BOOLEAN( 0 , "track", &opts.track, "track"),
+		OPT_SET_INT( 0 , "track",  &opts.track, "track",
+			BRANCH_TRACK_EXPLICIT),
 		OPT_BOOLEAN('f', NULL, &opts.force, "force"),
 		OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
 		OPT_END(),
@@ -512,7 +508,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 
 	git_config(git_checkout_config);
 
-	opts.track = branch_track;
+	opts.track = git_branch_track;
 
 	argc = parse_options(argc, argv, options, checkout_usage, 0);
 	if (argc) {
@@ -541,7 +537,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		argc--;
 	}
 
-	if (!opts.new_branch && (opts.track != branch_track))
+	if (!opts.new_branch && (opts.track != git_branch_track))
 		die("git checkout: --track and --no-track require -b");
 
 	if (opts.force && opts.merge)
diff --git a/cache.h b/cache.h
index 9ebe7913b0..f16d341f52 100644
--- a/cache.h
+++ b/cache.h
@@ -425,6 +425,15 @@ enum safe_crlf {
 
 extern enum safe_crlf safe_crlf;
 
+enum branch_track {
+	BRANCH_TRACK_NEVER = 0,
+	BRANCH_TRACK_REMOTE,
+	BRANCH_TRACK_ALWAYS,
+	BRANCH_TRACK_EXPLICIT,
+};
+
+extern enum branch_track git_branch_track;
+
 #define GIT_REPO_VERSION 0
 extern int repository_format_version;
 extern int check_repository_format(void);
diff --git a/config.c b/config.c
index cba2bcfb67..062449459e 100644
--- a/config.c
+++ b/config.c
@@ -471,6 +471,14 @@ int git_default_config(const char *var, const char *value)
 		whitespace_rule_cfg = parse_whitespace_rule(value);
 		return 0;
 	}
+	if (!strcmp(var, "branch.autosetupmerge")) {
+		if (value && !strcasecmp(value, "always")) {
+			git_branch_track = BRANCH_TRACK_ALWAYS;
+			return 0;
+		}
+		git_branch_track = git_config_bool(var, value);
+		return 0;
+	}
 
 	/* Add other config variables here and to Documentation/config.txt. */
 	return 0;
diff --git a/environment.c b/environment.c
index 3527f1663f..6739a3f417 100644
--- a/environment.c
+++ b/environment.c
@@ -37,6 +37,7 @@ const char *excludes_file;
 int auto_crlf = 0;	/* 1: both ways, -1: only when adding git objects */
 enum safe_crlf safe_crlf = SAFE_CRLF_WARN;
 unsigned whitespace_rule_cfg = WS_DEFAULT_RULE;
+enum branch_track git_branch_track = BRANCH_TRACK_REMOTE;
 
 /* This is set by setup_git_dir_gently() and/or git_default_config() */
 char *git_work_tree_cfg;
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index d21081d0f1..38a90adad6 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -15,6 +15,9 @@ test_expect_success \
     'echo Hello > A &&
      git update-index --add A &&
      git-commit -m "Initial commit." &&
+     echo World >> A &&
+     git update-index --add A &&
+     git-commit -m "Second commit." &&
      HEAD=$(git rev-parse --verify HEAD)'
 
 test_expect_success \
@@ -171,7 +174,9 @@ test_expect_success 'test overriding tracking setup via --no-track' \
      ! test "$(git config branch.my2.merge)" = refs/heads/master'
 
 test_expect_success 'no tracking without .fetch entries' \
-    'git branch --track my6 s &&
+    'git config branch.autosetupmerge true &&
+     git branch my6 s &&
+     git config branch.automsetupmerge false &&
      test -z "$(git config branch.my6.remote)" &&
      test -z "$(git config branch.my6.merge)"'
 
@@ -192,6 +197,21 @@ test_expect_success 'test deleting branch without config' \
     'git branch my7 s &&
      test "$(git branch -d my7 2>&1)" = "Deleted branch my7."'
 
+test_expect_success 'test --track without .fetch entries' \
+    'git branch --track my8 &&
+     test "$(git config branch.my8.remote)" &&
+     test "$(git config branch.my8.merge)"'
+
+test_expect_success \
+    'branch from non-branch HEAD w/autosetupmerge=always' \
+    'git config branch.autosetupmerge always &&
+     git branch my9 HEAD^ &&
+     git config branch.autosetupmerge false'
+
+test_expect_success \
+    'branch from non-branch HEAD w/--track causes failure' \
+    '!(git branch --track my10 HEAD^)'
+
 # Keep this test last, as it changes the current branch
 cat >expect <<EOF
 0000000000000000000000000000000000000000 $HEAD $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	branch: Created from master
diff --git a/t/t7201-co.sh b/t/t7201-co.sh
index 724adef0bf..63915cd87b 100755
--- a/t/t7201-co.sh
+++ b/t/t7201-co.sh
@@ -313,4 +313,28 @@ test_expect_success 'checkout specific path while in subdirectory' '
 
 '
 
+test_expect_success \
+    'checkout w/--track sets up tracking' '
+    git config branch.autosetupmerge false &&
+    git checkout master &&
+    git checkout --track -b track1 &&
+    test "$(git config branch.track1.remote)" &&
+    test "$(git config branch.track1.merge)"'
+
+test_expect_success \
+    'checkout w/autosetupmerge=always sets up tracking' '
+    git config branch.autosetupmerge always &&
+    git checkout master &&
+    git checkout -b track2 &&
+    test "$(git config branch.track2.remote)" &&
+    test "$(git config branch.track2.merge)"
+    git config branch.autosetupmerge false'
+
+test_expect_success \
+    'checkout w/--track from non-branch HEAD fails' '
+    git checkout -b delete-me master &&
+    rm .git/refs/heads/delete-me &&
+    test refs/heads/delete-me = "$(git symbolic-ref HEAD)" &&
+    !(git checkout --track -b track)'
+
 test_done