Re: [PATCH v3 4/5] branch: add --recurse-submodules option for branch creation

  advice.c                           |   1 +
  advice.h                           |   1 +
  branch.c                           | 129 ++++++++++++-
  branch.h                           |  31 +++-
  builtin/branch.c                   |  40 +++-
  builtin/checkout.c                 |   3 +-
  builtin/submodule--helper.c        |  38 ++++
  submodule-config.c                 |  35 ++++
  submodule-config.h                 |  35 ++++
  submodule.c                        |  11 +-
  submodule.h                        |   3 +
  t/t3207-branch-submodule.sh        | 284 +++++++++++++++++++++++++++++
  14 files changed, 609 insertions(+), 13 deletions(-)
  create mode 100755 t/t3207-branch-submodule.sh

diff --git a/Documentation/config/advice.txt b/Documentation/config/advice.txt
index 063eec2511..e52262dc69 100644
--- a/Documentation/config/advice.txt
+++ b/Documentation/config/advice.txt

@@ -116,6 +116,9 @@ advice.*::
  	submoduleAlternateErrorStrategyDie::
  		Advice shown when a submodule.alternateErrorStrategy option
  		configured to "die" causes a fatal error.
+	submodulesNotUpdated::
+		Advice shown when a user runs a submodule command that fails
+		because `git submodule update` was not run.

  	addIgnoredFile::
  		Advice shown if a user attempts to add an ignored file to
  		the index.

diff --git a/Documentation/config/submodule.txt b/Documentation/config/submodule.txt
index ee454f8126..52b35964c0 100644
--- a/Documentation/config/submodule.txt
+++ b/Documentation/config/submodule.txt

@@ -72,6 +72,14 @@ submodule.recurse::
  	For these commands a workaround is to temporarily change the
  	configuration value by using `git -c submodule.recurse=0`.
  
+submodule.propagateBranches::
+	[EXPERIMENTAL] A boolean that enables branching support when
+	using `--recurse-submodules` or `submodule.recurse=true`.
+	Enabling this will allow certain commands to accept
+	`--recurse-submodules` and certain commands that already accept
+	`--recurse-submodules` will now consider branches.
+	Defaults to false.
+

diff --git a/branch.c b/branch.c
index 6b9d64cdf9..305154de0b 100644
--- a/branch.c
+++ b/branch.c

@@ -8,6 +8,8 @@

+void create_branches_recursively(struct repository *r, const char *name,
+				 const char *start_name,
+				 const char *tracking_name, int force,
+				 int reflog, int quiet, enum branch_track track,
+				 int dry_run)
+{
+	int i = 0;
+	char *branch_point = NULL;
+	struct object_id super_oid;
+	struct submodule_entry_list submodule_entry_list;
+
+	/* Perform dwim on start_name to get super_oid and branch_point. */
+	validate_branch_start(r, start_name, BRANCH_TRACK_NEVER, &super_oid,
+			      &branch_point);
+
+	/*
+	 * If we were not given an explicit name to track, then assume we are at
+	 * the top level and, just like the non-recursive case, the tracking
+	 * name is the branch point.
+	 */
+	if (!tracking_name)
+		tracking_name = branch_point;
+
+	submodules_of_tree(r, &super_oid, &submodule_entry_list);
+	/*
+	 * Before creating any branches, first check that the branch can
+	 * be created in every submodule.
+	 */
+	for (i = 0; i < submodule_entry_list.entry_nr; i++) {
+		if (submodule_entry_list.entries[i].repo == NULL) {
+			if (advice_enabled(ADVICE_SUBMODULES_NOT_UPDATED))
+				advise(_("You may try updating the submodules using 'git checkout %s && git submodule update --init'"),
+				       start_name);
+			die(_("submodule '%s': unable to find submodule"),

+			    submodule_entry_list.entries[i].submodule->name);
+		}
+
+		if (submodule_create_branch(
+			    submodule_entry_list.entries[i].repo,
+			    submodule_entry_list.entries[i].submodule, name,
+			    oid_to_hex(&submodule_entry_list.entries[i]
+						.name_entry->oid),
+			    tracking_name, force, reflog, quiet, track, 1))

+			die(_("submodule '%s': cannot create branch '%s'"),
+			    submodule_entry_list.entries[i].submodule->name,
+			    name);
+	}
+
+	create_branch(the_repository, name, start_name, force, 0, reflog, quiet,
+		      BRANCH_TRACK_NEVER, dry_run);

+	if (dry_run)
+		return;
+	/*
+	 * NEEDSWORK If tracking was set up in the superproject but not the
+	 * submodule, users might expect "git branch --recurse-submodules" to
+	 * fail or give a warning, but this is not yet implemented because it is
+	 * tedious to determine whether or not tracking was set up in the
+	 * superproject.
+	 */
+	setup_tracking(name, tracking_name, track, quiet, 0);
+
+	for (i = 0; i < submodule_entry_list.entry_nr; i++) {
+		if (submodule_create_branch(
+			    submodule_entry_list.entries[i].repo,
+			    submodule_entry_list.entries[i].submodule, name,
+			    oid_to_hex(&submodule_entry_list.entries[i]
+						.name_entry->oid),
+			    tracking_name, force, reflog, quiet, track, 0))

@@ -851,6 +874,9 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
  		git_config_set_multivar(buf.buf, NULL, NULL, CONFIG_FLAGS_MULTI_REPLACE);
  		strbuf_release(&buf);
  	} else if (!noncreate_actions && argc > 0 && argc <= 2) {
+		const char *branch_name = argv[0];
+		const char *start_name = argc == 2 ? argv[1] : head;
+
  		if (filter.kind != FILTER_REFS_BRANCHES)
  			die(_("The -a, and -r, options to 'git branch' do not take a branch name.\n"
  				  "Did you mean to use: -a|-r --list <pattern>?"));

@@ -858,10 +884,14 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
  		if (track == BRANCH_TRACK_OVERRIDE)
  			die(_("the '--set-upstream' option is no longer supported. Please use '--track' or '--set-upstream-to' instead."));
  
-		create_branch(the_repository,
-			      argv[0], (argc == 2) ? argv[1] : head,
-			      force, 0, reflog, quiet, track);
-
+		if (recurse_submodules) {
+			create_branches_recursively(the_repository, branch_name,
+						    start_name, NULL, force,
+						    reflog, quiet, track, 0);

+			return 0;
+		}
+		create_branch(the_repository, branch_name, start_name, force, 0,
+			      reflog, quiet, track, 0);

diff --git a/t/t3207-branch-submodule.sh b/t/t3207-branch-submodule.sh
new file mode 100755
index 0000000000..2dd0e2b01f
--- /dev/null
+++ b/t/t3207-branch-submodule.sh