refs API: make resolve_ref_unsafe() not set errno

avar · gitster · commit ed90f04155df · 2021-10-16T11:17:04.000-07:00
Change the resolve_ref_unsafe() wrapper function to use the underlying refs_werrres_ref_unsafe() directly. From a reading of the callers I determined that the only one who cared about errno was a sequencer.c caller added in e47c6ca (commit: move print_commit_summary() to libgit, 2017-11-24), I'm migrating it to using refs_werrres_ref_unsafe() directly. This adds another "set errno" instance, but in this case it's OK and idiomatic. We are setting it just before calling die_errno(). We could have some hypothetical die_errno_var(&saved_errno, ...) here, but I don't think it's worth it. The problem with errno is subtle action at distance, not this sort of thing. We already use this pattern in a couple of places in wrapper.c Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/refs.c b/refs.c
@@ -1785,8 +1785,10 @@ int refs_init_db(struct strbuf *err)
 const char *resolve_ref_unsafe(const char *refname, int resolve_flags,
 			       struct object_id *oid, int *flags)
 {
-	return refs_resolve_ref_unsafe(get_main_ref_store(the_repository), refname,
-				       resolve_flags, oid, flags);
+	int ignore_errno;
+
+	return refs_werrres_ref_unsafe(get_main_ref_store(the_repository), refname,
+				       resolve_flags, oid, flags, &ignore_errno);
 }
 
 int resolve_gitlink_ref(const char *submodule, const char *refname,
diff --git a/sequencer.c b/sequencer.c
@@ -1282,6 +1282,8 @@ void print_commit_summary(struct repository *r,
 	struct pretty_print_context pctx = {0};
 	struct strbuf author_ident = STRBUF_INIT;
 	struct strbuf committer_ident = STRBUF_INIT;
+	struct ref_store *refs;
+	int resolve_errno;
 
 	commit = lookup_commit(r, oid);
 	if (!commit)
@@ -1331,9 +1333,13 @@ void print_commit_summary(struct repository *r,
 	rev.diffopt.break_opt = 0;
 	diff_setup_done(&rev.diffopt);
 
-	head = resolve_ref_unsafe("HEAD", 0, NULL, NULL);
-	if (!head)
+	refs = get_main_ref_store(the_repository);
+	head = refs_werrres_ref_unsafe(refs, "HEAD", 0, NULL, NULL,
+				       &resolve_errno);
+	if (!head) {
+		errno = resolve_errno;
 		die_errno(_("unable to resolve HEAD after creating commit"));
+	}
 	if (!strcmp(head, "HEAD"))
 		head = _("detached HEAD");
 	else

Original file line number	Diff line number	Diff line change
`@@ -1785,8 +1785,10 @@ int refs_init_db(struct strbuf *err)`
`1785`	`1785`	`const char resolve_ref_unsafe(const char refname, int resolve_flags,`
`1786`	`1786`	`struct object_id oid, int flags)`
`1787`	`1787`	`{`
`1788`		`- return refs_resolve_ref_unsafe(get_main_ref_store(the_repository), refname,`
`1789`		`- resolve_flags, oid, flags);`
	`1788`	`+ int ignore_errno;`
	`1789`	`+`
	`1790`	`+ return refs_werrres_ref_unsafe(get_main_ref_store(the_repository), refname,`
	`1791`	`+ resolve_flags, oid, flags, &ignore_errno);`
`1790`	`1792`	`}`
`1791`	`1793`
`1792`	`1794`	`int resolve_gitlink_ref(const char submodule, const char refname,`