[PATCH v2 2/2] ref-filter: allow merged and no-merged filters

[Aaron Lipman <alipman88@gmail.com>]

Enable ref-filter to process multiple merged and no-merged filters, and
extend functionality to git branch, git tag and git for-each-ref. This
provides an easy way to check for branches that are "graduation
candidates:"

$ git branch --merged next --no-merged master

To accomplish this, store the merged and no-merged filters in two
commit_list structs (reachable_from and unreachable_from) rather than
using a single commit struct (merge_commit).

If passed more than one merged (or more than one no-merged) filter, refs
must be reachable from any one of the merged commits, and reachable from
none of the no-merged commits.

Signed-off-by: Aaron Lipman <alipman88@gmail.com>
---
 Documentation/git-branch.txt       |  6 +--
 Documentation/git-for-each-ref.txt |  6 +--
 Documentation/git-tag.txt          |  4 +-
 builtin/branch.c                   |  4 +-
 builtin/tag.c                      |  6 +--
 ref-filter.c                       | 71 ++++++++++++++++--------------
 ref-filter.h                       |  9 +---
 t/t3200-branch.sh                  |  4 +-
 t/t3201-branch-contains.sh         | 27 ++++++++++++
 t/t6302-for-each-ref-filter.sh     |  4 +-
 t/t7004-tag.sh                     |  2 +-
 11 files changed, 83 insertions(+), 60 deletions(-)

diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt
index 03c0824d52..8f0dbcd0ac 100644
--- a/Documentation/git-branch.txt
+++ b/Documentation/git-branch.txt
@@ -252,13 +252,11 @@ start-point is either a local or remote-tracking branch.
 
 --merged [<commit>]::
 	Only list branches whose tips are reachable from the
-	specified commit (HEAD if not specified). Implies `--list`,
-	incompatible with `--no-merged`.
+	specified commit (HEAD if not specified). Implies `--list`.
 
 --no-merged [<commit>]::
 	Only list branches whose tips are not reachable from the
-	specified commit (HEAD if not specified). Implies `--list`,
-	incompatible with `--merged`.
+	specified commit (HEAD if not specified). Implies `--list`.
 
 <branchname>::
 	The name of the branch to create or delete.
diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt
index 616ce46087..f8322a7be2 100644
--- a/Documentation/git-for-each-ref.txt
+++ b/Documentation/git-for-each-ref.txt
@@ -76,13 +76,11 @@ OPTIONS
 
 --merged[=<object>]::
 	Only list refs whose tips are reachable from the
-	specified commit (HEAD if not specified),
-	incompatible with `--no-merged`.
+	specified commit (HEAD if not specified).
 
 --no-merged[=<object>]::
 	Only list refs whose tips are not reachable from the
-	specified commit (HEAD if not specified),
-	incompatible with `--merged`.
+	specified commit (HEAD if not specified).
 
 --contains[=<object>]::
 	Only list refs which contain the specified commit (HEAD if not
diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index f6d9791780..786d4dfd6f 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt
@@ -149,11 +149,11 @@ This option is only applicable when listing tags without annotation lines.
 
 --merged [<commit>]::
 	Only list tags whose commits are reachable from the specified
-	commit (`HEAD` if not specified), incompatible with `--no-merged`.
+	commit (`HEAD` if not specified).
 
 --no-merged [<commit>]::
 	Only list tags whose commits are not reachable from the specified
-	commit (`HEAD` if not specified), incompatible with `--merged`.
+	commit (`HEAD` if not specified).
 
 --points-at <object>::
 	Only list tags of the given object (HEAD if not
diff --git a/builtin/branch.c b/builtin/branch.c
index e82301fb1b..4bdb700dd5 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -688,8 +688,8 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 	    !show_current && !unset_upstream && argc == 0)
 		list = 1;
 
-	if (filter.with_commit || filter.merge != REF_FILTER_MERGED_NONE || filter.points_at.nr ||
-	    filter.no_commit)
+	if (filter.with_commit || filter.no_commit ||
+	    filter.reachable_from || filter.unreachable_from || filter.points_at.nr)
 		list = 1;
 
 	if (!!delete + !!rename + !!copy + !!new_upstream + !!show_current +
diff --git a/builtin/tag.c b/builtin/tag.c
index 5cbd80dc3e..b1a0398c85 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -457,8 +457,8 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 		if (argc == 0)
 			cmdmode = 'l';
 		else if (filter.with_commit || filter.no_commit ||
-			 filter.points_at.nr || filter.merge_commit ||
-			 filter.lines != -1)
+			 filter.reachable_from || filter.unreachable_from ||
+			 filter.points_at.nr || filter.lines != -1)
 			cmdmode = 'l';
 	}
 
@@ -509,7 +509,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 		die(_("--no-contains option is only allowed in list mode"));
 	if (filter.points_at.nr)
 		die(_("--points-at option is only allowed in list mode"));
-	if (filter.merge_commit)
+	if (filter.reachable_from || filter.unreachable_from)
 		die(_("--merged and --no-merged options are only allowed in list mode"));
 	if (cmdmode == 'd')
 		return for_each_tag_name(argv, delete_tag, NULL);
diff --git a/ref-filter.c b/ref-filter.c
index 110bcd741a..c04dca47d1 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -2167,9 +2167,9 @@ static int ref_filter_handler(const char *refname, const struct object_id *oid,
 	 * obtain the commit using the 'oid' available and discard all
 	 * non-commits early. The actual filtering is done later.
 	 */
-	if (filter->merge_commit || filter->with_commit || filter->no_commit || filter->verbose) {
-		commit = lookup_commit_reference_gently(the_repository, oid,
-							1);
+	if (filter->reachable_from || filter->unreachable_from ||
+	    filter->with_commit || filter->no_commit || filter->verbose) {
+		commit = lookup_commit_reference_gently(the_repository, oid, 1);
 		if (!commit)
 			return 0;
 		/* We perform the filtering for the '--contains' option... */
@@ -2231,11 +2231,17 @@ void ref_array_clear(struct ref_array *array)
 	}
 }
 
-static void do_merge_filter(struct ref_filter_cbdata *ref_cbdata)
+static void do_merge_filter(struct ref_filter_cbdata *ref_cbdata, int reachable)
 {
+	struct commit_list *check_reachable_list = reachable ?
+		ref_cbdata->filter->reachable_from :
+		ref_cbdata->filter->unreachable_from;
+
+	if (!check_reachable_list)
+		return;
+
 	struct rev_info revs;
 	int i, old_nr;
-	struct ref_filter *filter = ref_cbdata->filter;
 	struct ref_array *array = ref_cbdata->array;
 	struct commit **to_clear = xcalloc(sizeof(struct commit *), array->nr);
 
@@ -2247,12 +2253,15 @@ static void do_merge_filter(struct ref_filter_cbdata *ref_cbdata)
 		to_clear[i] = item->commit;
 	}
 
-	filter->merge_commit->object.flags |= UNINTERESTING;
-	add_pending_object(&revs, &filter->merge_commit->object, "");
+	for (struct commit_list *rl = check_reachable_list; rl; rl = rl->next) {
+		struct commit *merge_commit = rl->item;
+		merge_commit->object.flags |= UNINTERESTING;
+		add_pending_object(&revs, &merge_commit->object, "");
 
-	revs.limited = 1;
-	if (prepare_revision_walk(&revs))
-		die(_("revision walk setup failed"));
+		revs.limited = 1;
+		if (prepare_revision_walk(&revs))
+			die(_("revision walk setup failed"));
+	}
 
 	old_nr = array->nr;
 	array->nr = 0;
@@ -2263,14 +2272,19 @@ static void do_merge_filter(struct ref_filter_cbdata *ref_cbdata)
 
 		int is_merged = !!(commit->object.flags & UNINTERESTING);
 
-		if (is_merged == (filter->merge == REF_FILTER_MERGED_INCLUDE))
+		if (is_merged == reachable)
 			array->items[array->nr++] = array->items[i];
 		else
 			free_array_item(item);
-	}
+  }
 
 	clear_commit_marks_many(old_nr, to_clear, ALL_REV_FLAGS);
-	clear_commit_marks(filter->merge_commit, ALL_REV_FLAGS);
+
+	while (check_reachable_list) {
+		struct commit *merge_commit = pop_commit(&check_reachable_list);
+		clear_commit_marks(merge_commit, ALL_REV_FLAGS);
+	}
+
 	free(to_clear);
 }
 
@@ -2322,8 +2336,8 @@ int filter_refs(struct ref_array *array, struct ref_filter *filter, unsigned int
 	clear_contains_cache(&ref_cbdata.no_contains_cache);
 
 	/*  Filters that need revision walking */
-	if (filter->merge_commit)
-		do_merge_filter(&ref_cbdata);
+	do_merge_filter(&ref_cbdata, 1);
+	do_merge_filter(&ref_cbdata, 0);
 
 	return ret;
 }
@@ -2541,31 +2555,22 @@ int parse_opt_merge_filter(const struct option *opt, const char *arg, int unset)
 {
 	struct ref_filter *rf = opt->value;
 	struct object_id oid;
-	int no_merged = starts_with(opt->long_name, "no");
 
 	BUG_ON_OPT_NEG(unset);
 
-	if (rf->merge) {
-		if (no_merged) {
-			return error(_("option `%s' is incompatible with --merged"),
-				     opt->long_name);
-		} else {
-			return error(_("option `%s' is incompatible with --no-merged"),
-				     opt->long_name);
-		}
-	}
-
-	rf->merge = no_merged
-		? REF_FILTER_MERGED_OMIT
-		: REF_FILTER_MERGED_INCLUDE;
-
 	if (get_oid(arg, &oid))
 		die(_("malformed object name %s"), arg);
 
-	rf->merge_commit = lookup_commit_reference_gently(the_repository,
-							  &oid, 0);
-	if (!rf->merge_commit)
+	struct commit *merge_commit = lookup_commit_reference_gently(the_repository,
+								     &oid, 0);
+
+	if (!merge_commit)
 		return error(_("option `%s' must point to a commit"), opt->long_name);
 
+	if (starts_with(opt->long_name, "no"))
+		commit_list_insert(merge_commit, &rf->unreachable_from);
+	else
+		commit_list_insert(merge_commit, &rf->reachable_from);
+
 	return 0;
 }
diff --git a/ref-filter.h b/ref-filter.h
index 8ecc33cdfa..feaef4a8fd 100644
--- a/ref-filter.h
+++ b/ref-filter.h
@@ -54,13 +54,8 @@ struct ref_filter {
 	struct oid_array points_at;
 	struct commit_list *with_commit;
 	struct commit_list *no_commit;
-
-	enum {
-		REF_FILTER_MERGED_NONE = 0,
-		REF_FILTER_MERGED_INCLUDE,
-		REF_FILTER_MERGED_OMIT
-	} merge;
-	struct commit *merge_commit;
+	struct commit_list *reachable_from;
+	struct commit_list *unreachable_from;
 
 	unsigned int with_commit_tag_algo : 1,
 		match_as_path : 1,
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 028c88d1b2..be8f61b751 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -1299,8 +1299,8 @@ test_expect_success '--merged catches invalid object names' '
 	test_must_fail git branch --merged 0000000000000000000000000000000000000000
 '
 
-test_expect_success '--merged is incompatible with --no-merged' '
-	test_must_fail git branch --merged HEAD --no-merged HEAD
+test_expect_success '--merged is compatible with --no-merged' '
+	git branch --merged master --no-merged master
 '
 
 test_expect_success '--list during rebase' '
diff --git a/t/t3201-branch-contains.sh b/t/t3201-branch-contains.sh
index cd205b5560..d1ec594f6a 100755
--- a/t/t3201-branch-contains.sh
+++ b/t/t3201-branch-contains.sh
@@ -226,6 +226,16 @@ test_expect_success 'multiple branch --contains' '
 	test_cmp expect actual
 '
 
+test_expect_success 'multiple branch --merged' '
+	git branch --merged next --merged master >actual &&
+	cat >expect <<-\EOF &&
+	  feature_a
+	  master
+	* next
+	EOF
+	test_cmp expect actual
+'
+
 test_expect_success 'multiple branch --no-contains' '
 	git branch --no-contains feature_a --no-contains feature_b >actual &&
 	cat >expect <<-\EOF &&
@@ -234,6 +244,14 @@ test_expect_success 'multiple branch --no-contains' '
 	test_cmp expect actual
 '
 
+test_expect_success 'multiple branch --no-merged' '
+	git branch --no-merged next --no-merged master >actual &&
+	cat >expect <<-\EOF &&
+	  feature_b
+	EOF
+	test_cmp expect actual
+'
+
 test_expect_success 'branch --contains combined with --no-contains' '
 	git checkout master &&
 	git merge feature_a &&
@@ -247,4 +265,13 @@ test_expect_success 'branch --contains combined with --no-contains' '
 	test_cmp expect actual
 '
 
+test_expect_success 'branch --merged combined with --no-merged' '
+	git branch --merged next --no-merged master >actual &&
+	cat >expect <<-\EOF &&
+	  feature_b
+	* next
+	EOF
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t6302-for-each-ref-filter.sh b/t/t6302-for-each-ref-filter.sh
index 35408d53fd..781e470aea 100755
--- a/t/t6302-for-each-ref-filter.sh
+++ b/t/t6302-for-each-ref-filter.sh
@@ -437,8 +437,8 @@ test_expect_success 'check %(if:notequals=<string>)' '
 	test_cmp expect actual
 '
 
-test_expect_success '--merged is incompatible with --no-merged' '
-	test_must_fail git for-each-ref --merged HEAD --no-merged HEAD
+test_expect_success '--merged is compatible with --no-merged' '
+	git for-each-ref --merged HEAD --no-merged HEAD
 '
 
 test_expect_success 'validate worktree atom' '
diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index 74b637deb2..7d544eceda 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh
@@ -2016,7 +2016,7 @@ test_expect_success '--merged can be used in non-list mode' '
 '
 
 test_expect_success '--merged is incompatible with --no-merged' '
-	test_must_fail git tag --merged HEAD --no-merged HEAD
+	git tag --merged HEAD --no-merged HEAD
 '
 
 test_expect_success '--merged shows merged tags' '
-- 
2.24.3 (Apple Git-128)