Merge branch 'sb/submodule-recursive-absorb'

When a submodule "A", which has another submodule "B" nested within
it, is "absorbed" into the top-level superproject, the inner
submodule "B" used to be left in a strange state.  The logic to
adjust the .git pointers in these submodules has been corrected.

* sb/submodule-recursive-absorb:
  submodule absorbing: fix worktree/gitdir pointers recursively for non-moves
  cache.h: expose the dying procedure for reading gitlinks
  setup: add gentle version of resolve_git_dir

cache.h

@@ -507,9 +507,12 @@ extern int is_nonbare_repository_dir(struct strbuf *path);
 #define READ_GITFILE_ERR_NO_PATH 6
 #define READ_GITFILE_ERR_NOT_A_REPO 7
 #define READ_GITFILE_ERR_TOO_LARGE 8
+extern void read_gitfile_error_die(int error_code, const char *path, const char *dir);
 extern const char *read_gitfile_gently(const char *path, int *return_error_code);
 #define read_gitfile(path) read_gitfile_gently((path), NULL)
-extern const char *resolve_gitdir(const char *suspect);
+extern const char *resolve_gitdir_gently(const char *suspect, int *return_error_code);
+#define resolve_gitdir(path) resolve_gitdir_gently((path), NULL)
+
 extern void set_git_work_tree(const char *tree);
 
 #define ALTERNATE_DB_ENVIRONMENT "GIT_ALTERNATE_OBJECT_DIRECTORIES"

setup.c

@@ -486,6 +486,30 @@ int verify_repository_format(const struct repository_format *format,
 	return 0;
 }
 
+void read_gitfile_error_die(int error_code, const char *path, const char *dir)
+{
+	switch (error_code) {
+	case READ_GITFILE_ERR_STAT_FAILED:
+	case READ_GITFILE_ERR_NOT_A_FILE:
+		/* non-fatal; follow return path */
+		break;
+	case READ_GITFILE_ERR_OPEN_FAILED:
+		die_errno("Error opening '%s'", path);
+	case READ_GITFILE_ERR_TOO_LARGE:
+		die("Too large to be a .git file: '%s'", path);
+	case READ_GITFILE_ERR_READ_FAILED:
+		die("Error reading %s", path);
+	case READ_GITFILE_ERR_INVALID_FORMAT:
+		die("Invalid gitfile format: %s", path);
+	case READ_GITFILE_ERR_NO_PATH:
+		die("No path in gitfile: %s", path);
+	case READ_GITFILE_ERR_NOT_A_REPO:
+		die("Not a git repository: %s", dir);
+	default:
+		die("BUG: unknown error code");
+	}
+}
+
 /*
  * Try to read the location of the git directory from the .git file,
  * return path to git directory if found.
@@ -559,28 +583,8 @@ const char *read_gitfile_gently(const char *path, int *return_error_code)
 cleanup_return:
 	if (return_error_code)
 		*return_error_code = error_code;
-	else if (error_code) {
-		switch (error_code) {
-		case READ_GITFILE_ERR_STAT_FAILED:
-		case READ_GITFILE_ERR_NOT_A_FILE:
-			/* non-fatal; follow return path */
-			break;
-		case READ_GITFILE_ERR_OPEN_FAILED:
-			die_errno("Error opening '%s'", path);
-		case READ_GITFILE_ERR_TOO_LARGE:
-			die("Too large to be a .git file: '%s'", path);
-		case READ_GITFILE_ERR_READ_FAILED:
-			die("Error reading %s", path);
-		case READ_GITFILE_ERR_INVALID_FORMAT:
-			die("Invalid gitfile format: %s", path);
-		case READ_GITFILE_ERR_NO_PATH:
-			die("No path in gitfile: %s", path);
-		case READ_GITFILE_ERR_NOT_A_REPO:
-			die("Not a git repository: %s", dir);
-		default:
-			assert(0);
-		}
-	}
+	else if (error_code)
+		read_gitfile_error_die(error_code, path, dir);
 
 	free(buf);
 	return error_code ? NULL : path;
@@ -1017,11 +1021,11 @@ const char *setup_git_directory(void)
 	return setup_git_directory_gently(NULL);
 }
 
-const char *resolve_gitdir(const char *suspect)
+const char *resolve_gitdir_gently(const char *suspect, int *return_error_code)
 {
 	if (is_git_directory(suspect))
 		return suspect;
-	return read_gitfile(suspect);
+	return read_gitfile_gently(suspect, return_error_code);
 }
 
 /* if any standard file descriptor is missing open it to /dev/null */

submodule.c

@@ -1437,23 +1437,58 @@ void absorb_git_dir_into_superproject(const char *prefix,
 				      const char *path,
 				      unsigned flags)
 {
-	const char *sub_git_dir, *v;
-	char *real_sub_git_dir = NULL, *real_common_git_dir = NULL;
+	int err_code;
+	const char *sub_git_dir;
 	struct strbuf gitdir = STRBUF_INIT;
-
 	strbuf_addf(&gitdir, "%s/.git", path);
-	sub_git_dir = resolve_gitdir(gitdir.buf);
+	sub_git_dir = resolve_gitdir_gently(gitdir.buf, &err_code);
 
 	/* Not populated? */
-	if (!sub_git_dir)
-		goto out;
+	if (!sub_git_dir) {
+		char *real_new_git_dir;
+		const char *new_git_dir;
+		const struct submodule *sub;
+
+		if (err_code == READ_GITFILE_ERR_STAT_FAILED) {
+			/* unpopulated as expected */
+			strbuf_release(&gitdir);
+			return;
+		}
+
+		if (err_code != READ_GITFILE_ERR_NOT_A_REPO)
+			/* We don't know what broke here. */
+			read_gitfile_error_die(err_code, path, NULL);
+
+		/*
+		* Maybe populated, but no git directory was found?
+		* This can happen if the superproject is a submodule
+		* itself and was just absorbed. The absorption of the
+		* superproject did not rewrite the git file links yet,
+		* fix it now.
+		*/
+		sub = submodule_from_path(null_sha1, path);
+		if (!sub)
+			die(_("could not lookup name for submodule '%s'"), path);
+		new_git_dir = git_path("modules/%s", sub->name);
+		if (safe_create_leading_directories_const(new_git_dir) < 0)
+			die(_("could not create directory '%s'"), new_git_dir);
+		real_new_git_dir = real_pathdup(new_git_dir);
+		connect_work_tree_and_git_dir(path, real_new_git_dir);
 
+		free(real_new_git_dir);
+	} else {
 		/* Is it already absorbed into the superprojects git dir? */
-	real_sub_git_dir = real_pathdup(sub_git_dir);
-	real_common_git_dir = real_pathdup(get_git_common_dir());
-	if (!skip_prefix(real_sub_git_dir, real_common_git_dir, &v))
+		char *real_sub_git_dir = real_pathdup(sub_git_dir);
+		char *real_common_git_dir = real_pathdup(get_git_common_dir());
+
+		if (!starts_with(real_sub_git_dir, real_common_git_dir))
 			relocate_single_git_dir_into_superproject(prefix, path);
 
+		free(real_sub_git_dir);
+		free(real_common_git_dir);
+	}
+	strbuf_release(&gitdir);
+
 	if (flags & ABSORB_GITDIR_RECURSE_SUBMODULES) {
 		struct child_process cp = CHILD_PROCESS_INIT;
 		struct strbuf sb = STRBUF_INIT;
@@ -1478,9 +1513,4 @@ void absorb_git_dir_into_superproject(const char *prefix,
 
 		strbuf_release(&sb);
 	}
-
-out:
-	strbuf_release(&gitdir);
-	free(real_sub_git_dir);
-	free(real_common_git_dir);
 }

t/t7412-submodule-absorbgitdirs.sh

@@ -64,6 +64,33 @@ test_expect_success 'absorb the git dir in a nested submodule' '
 	test_cmp expect.2 actual.2
 '
 
+test_expect_success 're-setup nested submodule' '
+	# un-absorb the direct submodule, to test if the nested submodule
+	# is still correct (needs a rewrite of the gitfile only)
+	rm -rf sub1/.git &&
+	mv .git/modules/sub1 sub1/.git &&
+	GIT_WORK_TREE=. git -C sub1 config --unset core.worktree &&
+	# fixup the nested submodule
+	echo "gitdir: ../.git/modules/nested" >sub1/nested/.git &&
+	GIT_WORK_TREE=../../../nested git -C sub1/.git/modules/nested config \
+		core.worktree "../../../nested" &&
+	# make sure this re-setup is correct
+	git status --ignore-submodules=none
+'
+
+test_expect_success 'absorb the git dir in a nested submodule' '
+	git status >expect.1 &&
+	git -C sub1/nested rev-parse HEAD >expect.2 &&
+	git submodule absorbgitdirs &&
+	test -f sub1/.git &&
+	test -f sub1/nested/.git &&
+	test -d .git/modules/sub1/modules/nested &&
+	git status >actual.1 &&
+	git -C sub1/nested rev-parse HEAD >actual.2 &&
+	test_cmp expect.1 actual.1 &&
+	test_cmp expect.2 actual.2
+'
+
 test_expect_success 'setup a gitlink with missing .gitmodules entry' '
 	git init sub2 &&
 	test_commit -C sub2 first &&