[PATCH v4 6/9] builtin/clone: move setup of alternates for non-shared local clones

@@ -181,7 +181,7 @@ static int add_one_alternate(struct string_list_item *item, void *cb_data)
 	return 0;
 }
 
-static void copy_alternates(struct strbuf *src, const char *src_repo)
+static void read_alternates(struct strvec *alternates, const char *src_repo)
 {
 	/*
 	 * Read from the source objects/info/alternates file

@@ -195,29 +195,41 @@ static void copy_alternates(struct strbuf *src, const char *src_repo)
 	 * to turn entries with paths relative to the original
 	 * absolute, so that they can be used in the new repository.
 	 */
-	FILE *in = xfopen(src->buf, "r");
+	FILE *in;
+	struct strbuf path = STRBUF_INIT;
 	struct strbuf line = STRBUF_INIT;
 
+	strbuf_addf(&path, "%s/objects/info/alternates", src_repo);
+
+	in = fopen(path.buf, "r");
+	if (!in) {
+		if (errno == ENOENT)
+			goto out;
+		die_errno("could not read alternates file '%s'", path.buf);
+	}
+
 	while (strbuf_getline(&line, in) != EOF) {
 		char *abs_path;
 		if (!line.len || line.buf[0] == '#')
 			continue;
 		if (is_absolute_path(line.buf)) {
-			odb_add_to_alternates_file(the_repository->objects,
-						   line.buf);
+			strvec_push(alternates, line.buf);
 			continue;
 		}
 		abs_path = mkpathdup("%s/objects/%s", src_repo, line.buf);
 		if (!normalize_path_copy(abs_path, abs_path))
-			odb_add_to_alternates_file(the_repository->objects,
-						   abs_path);
+			strvec_push(alternates, abs_path);
 		else
 			warning("skipping invalid relative alternate: %s/%s",
 				src_repo, line.buf);
 		free(abs_path);
 	}
+
+out:
+	strbuf_release(&path);
 	strbuf_release(&line);
-	fclose(in);
+	if (in)
+		fclose(in);
 }
 
 static void collect_alternates(struct strvec *alternates,

@@ -242,6 +254,8 @@ static void collect_alternates(struct strvec *alternates,
 		get_common_dir(&commondir, src_repo);
 		if (option_shared)
 			strvec_pushf(alternates, "%s/objects", commondir.buf);
+		else
+			read_alternates(alternates, commondir.buf);
 
 		strbuf_release(&commondir);
 	}

@@ -320,11 +334,9 @@ static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,
 			continue;
 		}
 
-		/* Files that cannot be copied bit-for-bit... */
-		if (!fspathcmp(iter->relative_path, "info/alternates")) {
-			copy_alternates(src, src_repo);
+		/* Alternates were already handled earlier. */
+		if (!fspathcmp(iter->relative_path, "info/alternates"))
 			continue;
-		}
 
 		if (unlink(dest->buf) && errno != ENOENT)
 			die_errno(_("failed to unlink '%s'"), dest->buf);

@@ -383,4 +383,29 @@ test_expect_success 'dissociate from repo with commit graph' '
 	git clone --no-local --reference graph.git --dissociate orig clone
 '
 
+test_expect_success 'local clone from linked worktree carries over alternates' '
+	rm -fr base derived derived-wt dst expect &&
+	git init base &&
+	test_commit -C base one &&
+	git clone --shared base derived &&
+	git -C derived worktree add ../derived-wt &&
+	git clone derived-wt dst &&
+	echo "$(pwd)/base/.git/objects" >expect &&
+	test_cmp expect dst/.git/objects/info/alternates &&
+	git -C dst fsck
+'
+
+test_expect_success 'local clone from linked worktree resolves relative alternates' '
+	rm -fr base derived derived-wt dst expect &&
+	git init base &&
+	test_commit -C base one &&
+	git clone --shared base derived &&
+	echo "../../../base/.git/objects" >derived/.git/objects/info/alternates &&
+	git -C derived worktree add ../derived-wt &&
+	git clone derived-wt dst &&
+	echo "$(pwd)/base/.git/objects" >expect &&
+	test_cmp expect dst/.git/objects/info/alternates &&
+	git -C dst fsck
+'
+
 test_done