Merge branch 'lh/branch-merged'

* lh/branch-merged:
  Add tests for `branch --[no-]merged`
  git-branch.txt: compare --contains, --merged and --no-merged
  git-branch: add support for --merged and --no-merged

Documentation/git-branch.txt

@@ -8,7 +8,7 @@ git-branch - List, create, or delete branches
 SYNOPSIS
 --------
 [verse]
-'git-branch' [--color | --no-color] [-r | -a]
+'git-branch' [--color | --no-color] [-r | -a] [--merged | --no-merged]
 	   [-v [--abbrev=<length> | --no-abbrev]]
 	   [--contains <commit>]
 'git-branch' [--track | --no-track] [-l] [-f] <branchname> [<start-point>]
@@ -24,6 +24,8 @@ and option `-a` shows both.
 With `--contains <commit>`, shows only the branches that
 contains the named commit (in other words, the branches whose
 tip commits are descendant of the named commit).
+With `--merged`, only branches merged into HEAD will be listed, and
+with `--no-merged` only branches not merged into HEAD will be listed.
 
 In its second form, a new branch named <branchname> will be created.
 It will start out with a head equal to the one given as <start-point>.
@@ -118,6 +120,15 @@ OPTIONS
 --no-track::
 	Ignore the branch.autosetupmerge configuration variable.
 
+--contains <commit>::
+	Only list branches which contain the specified commit.
+
+--merged::
+	Only list branches which are fully contained by HEAD.
+
+--no-merged::
+	Do not list branches which are fully contained by HEAD.
+
 <branchname>::
 	The name of the branch to create or delete.
 	The new branch name must pass all checks defined by
@@ -175,6 +186,18 @@ If you are creating a branch that you want to immediately checkout, it's
 easier to use the git checkout command with its `-b` option to create
 a branch and check it out with a single command.
 
+The options `--contains`, `--merged` and `--no-merged` serves three related
+but different purposes:
+
+- `--contains <commit>` is used to find all branches which will need
+  special attention if <commit> were to be rebased or amended, since those
+  branches contain the specified <commit>.
+
+- `--merged` is used to find all branches which can be safely deleted,
+  since those branches are fully contained by HEAD.
+
+- `--no-merged` is used to find branches which are candidates for merging
+  into HEAD, since those branches are not fully contained by HEAD.
 
 Author
 ------

builtin-branch.c

@@ -15,7 +15,7 @@
 #include "branch.h"
 
 static const char * const builtin_branch_usage[] = {
-	"git-branch [options] [-r | -a]",
+	"git-branch [options] [-r | -a] [--merged | --no-merged]",
 	"git-branch [options] [-l] [-f] <branchname> [<start-point>]",
 	"git-branch [options] [-r] (-d | -D) <branchname>",
 	"git-branch [options] (-m | -M) [<oldbranch>] <newbranch>",
@@ -46,6 +46,8 @@ enum color_branch {
 	COLOR_BRANCH_CURRENT = 4,
 };
 
+static int mergefilter = -1;
+
 static int parse_branch_color_slot(const char *var, int ofs)
 {
 	if (!strcasecmp(var+ofs, "plain"))
@@ -210,6 +212,7 @@ static int append_ref(const char *refname, const unsigned char *sha1, int flags,
 	struct ref_item *newitem;
 	int kind = REF_UNKNOWN_TYPE;
 	int len;
+	static struct commit_list branch;
 
 	/* Detect kind */
 	if (!prefixcmp(refname, "refs/heads/")) {
@@ -231,6 +234,16 @@ static int append_ref(const char *refname, const unsigned char *sha1, int flags,
 	if ((kind & ref_list->kinds) == 0)
 		return 0;
 
+	if (mergefilter > -1) {
+		branch.item = lookup_commit_reference_gently(sha1, 1);
+		if (!branch.item)
+			die("Unable to lookup tip of branch %s", refname);
+		if (mergefilter == 0 && has_commit(head_sha1, &branch))
+			return 0;
+		if (mergefilter == 1 && !has_commit(head_sha1, &branch))
+			return 0;
+	}
+
 	/* Resize buffer */
 	if (ref_list->index >= ref_list->alloc) {
 		ref_list->alloc = alloc_nr(ref_list->alloc);
@@ -444,6 +457,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 		OPT_BIT('M', NULL, &rename, "move/rename a branch, even if target exists", 2),
 		OPT_BOOLEAN('l', NULL, &reflog, "create the branch's reflog"),
 		OPT_BOOLEAN('f', NULL, &force_create, "force creation (when already exists)"),
+		OPT_SET_INT(0, "merged", &mergefilter, "list only merged branches", 1),
 		OPT_END(),
 	};
 

t/t3201-branch-contains.sh

 #!/bin/sh
 
-test_description='branch --contains <commit>'
+test_description='branch --contains <commit>, --merged, and --no-merged'
 
 . ./test-lib.sh
 
@@ -55,4 +55,44 @@ test_expect_success 'branch --contains=side' '
 
 '
 
+test_expect_success 'side: branch --merged' '
+
+	git branch --merged >actual &&
+	{
+		echo "  master" &&
+		echo "* side"
+	} >expect &&
+	test_cmp expect actual
+
+'
+
+test_expect_success 'side: branch --no-merged' '
+
+	git branch --no-merged >actual &&
+	>expect &&
+	test_cmp expect actual
+
+'
+
+test_expect_success 'master: branch --merged' '
+
+	git checkout master &&
+	git branch --merged >actual &&
+	{
+		echo "* master"
+	} >expect &&
+	test_cmp expect actual
+
+'
+
+test_expect_success 'master: branch --no-merged' '
+
+	git branch --no-merged >actual &&
+	{
+		echo "  side"
+	} >expect &&
+	test_cmp expect actual
+
+'
+
 test_done