[PATCHv2 4/5] submodule--helper, module_clone: always operate on absolute paths

[Stefan Beller <sbeller@google.com>]

When giving relative paths to `relative_path` to compute a relative path
from one directory to another, this may fail in `relative_path`.
Make sure both arguments to `relative_path` are always absolute.

Signed-off-by: Stefan Beller <sbeller@google.com>
---

Notes:
    Notice how the 2 relative path calls
      relative_path(sm_gitdir, path, &rel_path)
      relative_path(path, sm_gitdir, &rel_path)
    now have the same arguments, just switched?
    The symmetry there looks nice to read.
    
    This proposal is slightly more code than the previous patch,
    but looking at the end result

 builtin/submodule--helper.c | 36 +++++++++++++++++++++++-------------
 t/t7400-submodule-basic.sh  |  2 +-
 2 files changed, 24 insertions(+), 14 deletions(-)

diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index 0b9f546..56c3033 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -157,8 +157,8 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	const char *reference = NULL, *depth = NULL;
 	int quiet = 0;
 	FILE *submodule_dot_git;
-	char *sm_gitdir, *cwd, *p;
-	struct strbuf rel_path = STRBUF_INIT;
+	char *sm_gitdir, *p;
+	struct strbuf rel_path = STRBUF_INIT; /* for relative_path */
 	struct strbuf sb = STRBUF_INIT;
 
 	struct option module_clone_options[] = {
@@ -200,6 +200,25 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	strbuf_addf(&sb, "%s/modules/%s", get_git_dir(), name);
 	sm_gitdir = strbuf_detach(&sb, NULL);
 
+
+	if (!is_absolute_path(sm_gitdir)) {
+		char *cwd = xgetcwd();
+		strbuf_addf(&sb, "%s/%s", cwd, sm_gitdir);
+		sm_gitdir = strbuf_detach(&sb, 0);
+		free(cwd);
+	}
+
+	if (!is_absolute_path(path)) {
+		/*
+		 * TODO: add prefix here once we allow calling from non root
+		 * directory?
+		 */
+		strbuf_addf(&sb, "%s/%s",
+			    get_git_work_tree(),
+			    path);
+		path = strbuf_detach(&sb, 0);
+	}
+
 	if (!file_exists(sm_gitdir)) {
 		if (safe_create_leading_directories_const(sm_gitdir) < 0)
 			die(_("could not create directory '%s'"), sm_gitdir);
@@ -221,7 +240,6 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	submodule_dot_git = fopen(sb.buf, "w");
 	if (!submodule_dot_git)
 		die_errno(_("cannot open file '%s'"), sb.buf);
-
 	fprintf(submodule_dot_git, "gitdir: %s\n",
 		relative_path(sm_gitdir, path, &rel_path));
 	if (fclose(submodule_dot_git))
@@ -229,24 +247,16 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 	strbuf_reset(&sb);
 	strbuf_reset(&rel_path);
 
-	cwd = xgetcwd();
 	/* Redirect the worktree of the submodule in the superproject's config */
-	if (!is_absolute_path(sm_gitdir)) {
-		strbuf_addf(&sb, "%s/%s", cwd, sm_gitdir);
-		free(sm_gitdir);
-		sm_gitdir = strbuf_detach(&sb, NULL);
-	}
-
-	strbuf_addf(&sb, "%s/%s", cwd, path);
 	p = git_pathdup_submodule(path, "config");
 	if (!p)
 		die(_("could not get submodule directory for '%s'"), path);
 	git_config_set_in_file(p, "core.worktree",
-			       relative_path(sb.buf, sm_gitdir, &rel_path));
+			       relative_path(path, sm_gitdir, &rel_path));
 	strbuf_release(&sb);
 	strbuf_release(&rel_path);
 	free(sm_gitdir);
-	free(cwd);
+
 	free(p);
 	return 0;
 }
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index fc11809..ea3fabb 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -818,7 +818,7 @@ test_expect_success 'submodule add --name allows to replace a submodule with ano
 	)
 '
 
-test_expect_failure 'recursive relative submodules stay relative' '
+test_expect_success 'recursive relative submodules stay relative' '
 	test_when_finished "rm -rf super clone2 subsub sub3" &&
 	mkdir subsub &&
 	(
-- 
2.5.0.264.g39f00fe