[PATCH] branch: move multiple branches in a single --force

["Andrea Stacchiotti via GitGitGadget" <gitgitgadget@gmail.com>]

From: Andrea Stacchiotti <andreastacchiotti@gmail.com>

Using either the 1-arg or 2-args form of --force
it is possible to only move one branch at a time,
to HEAD and <arg2> respectively.

Allow moving multiple branches to a single target by giving
'git branch --force b1 b2 b3 ... dest' cp-like semantics,
all the branches are moved/created to 'dest'.

The convention extends the 2-args form in the same way
'cp a b c ... dest' would do.

There could be another potential interpretation of
`--force a b c`: moving all 3 to HEAD, but the 2-args
form already changed the semantics to cp-like instead
of appending an implicit HEAD, so this seems the least
surprising way to support multiple moves.

No such change is done to the move/copy paths,
as such paths would error out anyway by trying
to create multiple branches of the same name.

Signed-off-by: Andrea Stacchiotti <andreastacchiotti@gmail.com>
---
    branch: Move multiple branches in a single --force

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1992%2F12345ieee%2Fmaster-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1992/12345ieee/master-v1
Pull-Request: https://github.com/git/git/pull/1992

 Documentation/git-branch.adoc |  2 +-
 builtin/branch.c              | 26 ++++++++++++++------------
 t/t3200-branch.sh             |  7 +++++++
 3 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/Documentation/git-branch.adoc b/Documentation/git-branch.adoc
index c0afddc424d..817b4a5d3f6 100644
--- a/Documentation/git-branch.adoc
+++ b/Documentation/git-branch.adoc
@@ -17,7 +17,7 @@ git branch [--color[=<when>] | --no-color] [--show-current]
 	   [(-r|--remotes) | (-a|--all)]
 	   [--list] [<pattern>...]
 git branch [--track[=(direct|inherit)] | --no-track] [-f]
-	   [--recurse-submodules] <branch-name> [<start-point>]
+	   [--recurse-submodules] <branch-name>... [<start-point>]
 git branch (--set-upstream-to=<upstream>|-u <upstream>) [<branch-name>]
 git branch --unset-upstream [<branch-name>]
 git branch (-m|-M) [<old-branch>] <new-branch>
diff --git a/builtin/branch.c b/builtin/branch.c
index c150131bd9f..8ba04568c15 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -31,7 +31,7 @@
 
 static const char * const builtin_branch_usage[] = {
 	N_("git branch [<options>] [-r | -a] [--merged] [--no-merged]"),
-	N_("git branch [<options>] [-f] [--recurse-submodules] <branch-name> [<start-point>]"),
+	N_("git branch [<options>] [-f] [--recurse-submodules] <branch-name>... [<start-point>]"),
 	N_("git branch [<options>] [-l] [<pattern>...]"),
 	N_("git branch [<options>] [-r] (-d | -D) <branch-name>..."),
 	N_("git branch [<options>] (-m | -M) [<old-branch>] <new-branch>"),
@@ -992,9 +992,9 @@ int cmd_branch(int argc,
 		strbuf_addf(&buf, "branch.%s.merge", branch->name);
 		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;
+	} else if (!noncreate_actions && argc > 0) {
+		const char *start_name = argc == 1 ? head : argv[argc - 1];
+		int iters = argc == 1 ? 1 : argc - 1;
 
 		if (filter.kind != FILTER_REFS_BRANCHES)
 			die(_("the -a, and -r, options to 'git branch' do not take a branch name.\n"
@@ -1003,15 +1003,17 @@ int cmd_branch(int argc,
 		if (track == BRANCH_TRACK_OVERRIDE)
 			die(_("the '--set-upstream' option is no longer supported. Please use '--track' or '--set-upstream-to' instead"));
 
-		if (recurse_submodules) {
-			create_branches_recursively(the_repository, branch_name,
-						    start_name, NULL, force,
-						    reflog, quiet, track, 0);
-			ret = 0;
-			goto out;
+		for (int i = 0; i < iters; i++) {
+			const char *branch_name = argv[i];
+
+			if (recurse_submodules)
+				create_branches_recursively(the_repository, branch_name,
+								start_name, NULL, force,
+								reflog, quiet, track, 0);
+			else
+				create_branch(the_repository, branch_name, start_name, force, 0,
+						reflog, quiet, track, 0);
 		}
-		create_branch(the_repository, branch_name, start_name, force, 0,
-			      reflog, quiet, track, 0);
 	} else
 		usage_with_options(builtin_branch_usage, options);
 
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index f3e720dc10d..7cd31ca7820 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -60,6 +60,13 @@ test_expect_success 'git branch --force abc should succeed when abc exists' '
 	test_cmp expect actual
 '
 
+test_expect_success 'git branch --force br1 br2 abc should create 2 new branches' '
+	git branch --force br1 br2 abc &&
+	test_ref_exists refs/heads/br1 &&
+	test_ref_exists refs/heads/br2 &&
+	git branch -d br1 br2
+'
+
 test_expect_success 'git branch a/b/c should create a branch' '
 	git branch a/b/c &&
 	test_ref_exists refs/heads/a/b/c

base-commit: 4c0e625c091d4c648cec7319bafaed3cc81658e5
-- 
gitgitgadget