[PATCH 4/4] reachable.c: make reachable reflogs for all per-worktree reflogs

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

Same reason as the previous commit, this is to avoid deleting objects
being referenced by per-worktree reflogs from other worktrees.
"logs/HEAD" is most important. "logs/refs/bisect" should not live long
enough to matter, but let's add it too for safety.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 reachable.c      |  7 ++++---
 revision.c       | 19 +++++++++++++++++++
 revision.h       |  3 +++
 t/t5304-prune.sh | 19 +++++++++++++++++++
 4 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/reachable.c b/reachable.c
index e5f9170..73915e0 100644
--- a/reachable.c
+++ b/reachable.c
@@ -156,7 +156,7 @@ int add_unseen_recent_objects_to_traversal(struct rev_info *revs,
 				      FOR_EACH_OBJECT_LOCAL_ONLY);
 }
 
-static void add_objects_from_worktree(struct rev_info *revs)
+static void add_objects_from_worktree(struct rev_info *revs, int mark_reflog)
 {
 	struct worktree **worktrees, **p;
 
@@ -176,7 +176,8 @@ static void add_objects_from_worktree(struct rev_info *revs)
 			o = parse_object_or_die(wt->head_sha1, "HEAD");
 			add_pending_object(revs, o, "");
 		}
-
+		if (mark_reflog)
+			add_worktree_reflogs_to_pending(revs, 0, wt);
 	}
 	free_worktrees(worktrees);
 
@@ -214,7 +215,7 @@ void mark_reachable_objects(struct rev_info *revs, int mark_reflog,
 	 * Add all objects from the in-core index file and detached
 	 * HEAD which is not included in the list above
 	 */
-	add_objects_from_worktree(revs);
+	add_objects_from_worktree(revs, mark_reflog);
 
 	cp.progress = progress;
 	cp.count = 0;
diff --git a/revision.c b/revision.c
index bbb6ff1..6a197a4 100644
--- a/revision.c
+++ b/revision.c
@@ -19,6 +19,7 @@
 #include "dir.h"
 #include "cache-tree.h"
 #include "bisect.h"
+#include "worktree.h"
 
 volatile show_early_output_fn_t show_early_output;
 
@@ -1245,6 +1246,24 @@ static int handle_one_reflog(const char *path, const struct object_id *oid,
 	return 0;
 }
 
+void add_worktree_reflogs_to_pending(struct rev_info *revs, unsigned flags,
+				     struct worktree *wt)
+{
+	struct all_refs_cb cb;
+	char *path;
+
+	cb.all_revs = revs;
+	cb.all_flags = flags;
+	path = xstrdup(worktree_git_path(wt, "logs/HEAD"));
+	if (file_exists(path))
+		handle_one_reflog(path, NULL, 0, &cb);
+	free(path);
+	path = xstrdup(worktree_git_path(wt, "logs/refs/bisect"));
+	if (file_exists(path))
+		handle_one_reflog(path, NULL, 0, &cb);
+	free(path);
+}
+
 void add_reflogs_to_pending(struct rev_info *revs, unsigned flags)
 {
 	struct all_refs_cb cb;
diff --git a/revision.h b/revision.h
index d06d098..9f3f148 100644
--- a/revision.h
+++ b/revision.h
@@ -30,6 +30,7 @@ struct log_info;
 struct string_list;
 struct saved_parents;
 struct index_state;
+struct worktree;
 
 struct rev_cmdline_info {
 	unsigned int nr;
@@ -272,6 +273,8 @@ extern void add_pending_sha1(struct rev_info *revs,
 
 extern void add_head_to_pending(struct rev_info *);
 extern void add_reflogs_to_pending(struct rev_info *, unsigned int flags);
+extern void add_worktree_reflogs_to_pending(struct rev_info *, unsigned int flags,
+					    struct worktree *);
 extern void add_index_objects_to_pending(struct rev_info *, unsigned int flags,
 					 const struct index_state *);
 
diff --git a/t/t5304-prune.sh b/t/t5304-prune.sh
index 683bdb0..6b1c456 100755
--- a/t/t5304-prune.sh
+++ b/t/t5304-prune.sh
@@ -304,4 +304,23 @@ test_expect_success 'prune: handle HEAD in multiple worktrees' '
 	test_cmp third-worktree/blob actual
 '
 
+test_expect_success 'prune: handle HEAD reflog in multiple worktrees' '
+	(
+		cd third-worktree &&
+		git config core.logAllRefUpdates true &&
+		echo "HEAD{1} blob for third-worktree" >blob &&
+		git add blob &&
+		git commit -m "second commit in third" &&
+		cp blob expected &&
+		echo "HEAD{0} blob for third-worktree" >blob &&
+		git add blob &&
+		git commit -m "third commit in third" &&
+		git show HEAD@{1}:blob >actual &&
+		test_cmp expected actual
+	) &&
+	git prune --expire=now &&
+	git -C third-worktree show HEAD@{1}:blob >actual &&
+	test_cmp third-worktree/expected actual
+'
+
 test_done
-- 
2.8.2.524.g6ff3d78