[PATCH v2 2/4] sequencer: treat CHERRY_PICK_HEAD as a pseudo ref

["Han-Wen Nienhuys via GitGitGadget" <gitgitgadget@gmail.com>]

From: Han-Wen Nienhuys <hanwen@google.com>

Check for existence and delete CHERRY_PICK_HEAD through ref functions.
This will help cherry-pick work with alternate ref storage backends.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
---
 builtin/merge.c |  2 +-
 path.c          |  1 -
 path.h          |  7 ++++---
 sequencer.c     | 42 ++++++++++++++++++++++++++----------------
 wt-status.c     |  4 ++--
 5 files changed, 33 insertions(+), 23 deletions(-)

diff --git a/builtin/merge.c b/builtin/merge.c
index 74829a838e..b9a89ba858 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1348,7 +1348,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 		else
 			die(_("You have not concluded your merge (MERGE_HEAD exists)."));
 	}
-	if (file_exists(git_path_cherry_pick_head(the_repository))) {
+	if (ref_exists("CHERRY_PICK_HEAD")) {
 		if (advice_resolve_conflict)
 			die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
 			    "Please, commit your changes before you merge."));
diff --git a/path.c b/path.c
index 8b2c753191..783cc2ae81 100644
--- a/path.c
+++ b/path.c
@@ -1528,7 +1528,6 @@ char *xdg_cache_home(const char *filename)
 	return NULL;
 }
 
-REPO_GIT_PATH_FUNC(cherry_pick_head, "CHERRY_PICK_HEAD")
 REPO_GIT_PATH_FUNC(revert_head, "REVERT_HEAD")
 REPO_GIT_PATH_FUNC(squash_msg, "SQUASH_MSG")
 REPO_GIT_PATH_FUNC(merge_msg, "MERGE_MSG")
diff --git a/path.h b/path.h
index 1f1bf8f87a..8941c018a9 100644
--- a/path.h
+++ b/path.h
@@ -170,7 +170,6 @@ void report_linked_checkout_garbage(void);
 	}
 
 struct path_cache {
-	const char *cherry_pick_head;
 	const char *revert_head;
 	const char *squash_msg;
 	const char *merge_msg;
@@ -182,9 +181,11 @@ struct path_cache {
 	const char *shallow;
 };
 
-#define PATH_CACHE_INIT { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL }
+#define PATH_CACHE_INIT                                              \
+	{                                                            \
+		NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL \
+	}
 
-const char *git_path_cherry_pick_head(struct repository *r);
 const char *git_path_revert_head(struct repository *r);
 const char *git_path_squash_msg(struct repository *r);
 const char *git_path_merge_msg(struct repository *r);
diff --git a/sequencer.c b/sequencer.c
index cc3f8fa88e..09e2ff659e 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -381,7 +381,8 @@ static void print_advice(struct repository *r, int show_hint,
 		 * (typically rebase --interactive) wants to take care
 		 * of the commit itself so remove CHERRY_PICK_HEAD
 		 */
-		unlink(git_path_cherry_pick_head(r));
+		refs_delete_ref(get_main_ref_store(r), "", "CHERRY_PICK_HEAD",
+				NULL, 0);
 		return;
 	}
 
@@ -1455,7 +1456,8 @@ static int do_commit(struct repository *r,
 				    author, opts, flags, &oid);
 		strbuf_release(&sb);
 		if (!res) {
-			unlink(git_path_cherry_pick_head(r));
+			refs_delete_ref(get_main_ref_store(r), "",
+					"CHERRY_PICK_HEAD", NULL, 0);
 			unlink(git_path_merge_msg(r));
 			if (!is_rebase_i(opts))
 				print_commit_summary(r, NULL, &oid,
@@ -1966,7 +1968,8 @@ static int do_pick_commit(struct repository *r,
 		flags |= ALLOW_EMPTY;
 	} else if (allow == 2) {
 		drop_commit = 1;
-		unlink(git_path_cherry_pick_head(r));
+		refs_delete_ref(get_main_ref_store(r), "", "CHERRY_PICK_HEAD",
+				NULL, 0);
 		unlink(git_path_merge_msg(r));
 		fprintf(stderr,
 			_("dropping %s %s -- patch contents already upstream\n"),
@@ -2305,8 +2308,10 @@ void sequencer_post_commit_cleanup(struct repository *r, int verbose)
 	struct replay_opts opts = REPLAY_OPTS_INIT;
 	int need_cleanup = 0;
 
-	if (file_exists(git_path_cherry_pick_head(r))) {
-		if (!unlink(git_path_cherry_pick_head(r)) && verbose)
+	if (refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD")) {
+		if (!refs_delete_ref(get_main_ref_store(r), "",
+				     "CHERRY_PICK_HEAD", NULL, 0) &&
+		    verbose)
 			warning(_("cancelling a cherry picking in progress"));
 		opts.action = REPLAY_PICK;
 		need_cleanup = 1;
@@ -2671,8 +2676,9 @@ static int create_seq_dir(struct repository *r)
 	enum replay_action action;
 	const char *in_progress_error = NULL;
 	const char *in_progress_advice = NULL;
-	unsigned int advise_skip = file_exists(git_path_revert_head(r)) ||
-				file_exists(git_path_cherry_pick_head(r));
+	unsigned int advise_skip =
+		file_exists(git_path_revert_head(r)) ||
+		refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD");
 
 	if (!sequencer_get_last_command(r, &action)) {
 		switch (action) {
@@ -2771,7 +2777,7 @@ static int rollback_single_pick(struct repository *r)
 {
 	struct object_id head_oid;
 
-	if (!file_exists(git_path_cherry_pick_head(r)) &&
+	if (!refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD") &&
 	    !file_exists(git_path_revert_head(r)))
 		return error(_("no cherry-pick or revert in progress"));
 	if (read_ref_full("HEAD", 0, &head_oid, NULL))
@@ -2874,7 +2880,8 @@ int sequencer_skip(struct repository *r, struct replay_opts *opts)
 		}
 		break;
 	case REPLAY_PICK:
-		if (!file_exists(git_path_cherry_pick_head(r))) {
+		if (!refs_ref_exists(get_main_ref_store(r),
+				     "CHERRY_PICK_HEAD")) {
 			if (action != REPLAY_PICK)
 				return error(_("no cherry-pick in progress"));
 			if (!rollback_is_safe())
@@ -3569,7 +3576,8 @@ static int do_merge(struct repository *r,
 				    oid_to_hex(&j->item->object.oid));
 
 		strbuf_release(&ref_name);
-		unlink(git_path_cherry_pick_head(r));
+		refs_delete_ref(get_main_ref_store(r), "", "CHERRY_PICK_HEAD",
+				NULL, 0);
 		rollback_lock_file(&lock);
 
 		rollback_lock_file(&lock);
@@ -4201,7 +4209,7 @@ static int continue_single_pick(struct repository *r)
 {
 	const char *argv[] = { "commit", NULL };
 
-	if (!file_exists(git_path_cherry_pick_head(r)) &&
+	if (!refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD") &&
 	    !file_exists(git_path_revert_head(r)))
 		return error(_("no cherry-pick or revert in progress"));
 	return run_command_v_opt(argv, RUN_GIT_CMD);
@@ -4318,9 +4326,10 @@ static int commit_staged_changes(struct repository *r,
 	}
 
 	if (is_clean) {
-		const char *cherry_pick_head = git_path_cherry_pick_head(r);
-
-		if (file_exists(cherry_pick_head) && unlink(cherry_pick_head))
+		if (refs_ref_exists(get_main_ref_store(r),
+				    "CHERRY_PICK_HEAD") &&
+		    refs_delete_ref(get_main_ref_store(r), "",
+				    "CHERRY_PICK_HEAD", NULL, 0))
 			return error(_("could not remove CHERRY_PICK_HEAD"));
 		if (!final_fixup)
 			return 0;
@@ -4379,7 +4388,8 @@ int sequencer_continue(struct repository *r, struct replay_opts *opts)
 
 	if (!is_rebase_i(opts)) {
 		/* Verify that the conflict has been resolved */
-		if (file_exists(git_path_cherry_pick_head(r)) ||
+		if (refs_ref_exists(get_main_ref_store(r),
+				    "CHERRY_PICK_HEAD") ||
 		    file_exists(git_path_revert_head(r))) {
 			res = continue_single_pick(r);
 			if (res)
@@ -5442,7 +5452,7 @@ int todo_list_rearrange_squash(struct todo_list *todo_list)
 
 int sequencer_determine_whence(struct repository *r, enum commit_whence *whence)
 {
-	if (file_exists(git_path_cherry_pick_head(r))) {
+	if (refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD")) {
 		struct object_id cherry_pick_head, rebase_head;
 
 		if (file_exists(git_path_seq_dir()))
diff --git a/wt-status.c b/wt-status.c
index d75399085d..c6abf2f3ca 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -1672,8 +1672,8 @@ void wt_status_get_state(struct repository *r,
 		state->merge_in_progress = 1;
 	} else if (wt_status_check_rebase(NULL, state)) {
 		;		/* all set */
-	} else if (!stat(git_path_cherry_pick_head(r), &st) &&
-			!get_oid("CHERRY_PICK_HEAD", &oid)) {
+	} else if (refs_ref_exists(get_main_ref_store(r), "CHERRY_PICK_HEAD") &&
+		   !get_oid("CHERRY_PICK_HEAD", &oid)) {
 		state->cherry_pick_in_progress = 1;
 		oidcpy(&state->cherry_pick_head_oid, &oid);
 	}
-- 
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