[PATCH 1/3] submodule: use absolute path for computing relative path connecting

[Stefan Beller <sbeller@google.com>]

This addresses a similar concern as in f8eaa0ba98b (submodule--helper,
module_clone: always operate on absolute paths, 2016-03-31)

When computing the relative path from one to another location, we
need to provide both locations as absolute paths to make sure the
computation of the relative path is correct.

While at it, change `real_work_tree` to be non const as we own
the memory.

Signed-off-by: Stefan Beller <sbeller@google.com>
---
 submodule.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/submodule.c b/submodule.c
index 6f7d883de9..66c5ce5a24 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1227,23 +1227,25 @@ void connect_work_tree_and_git_dir(const char *work_tree, const char *git_dir)
 {
 	struct strbuf file_name = STRBUF_INIT;
 	struct strbuf rel_path = STRBUF_INIT;
-	const char *real_work_tree = xstrdup(real_path(work_tree));
+	char *real_git_dir = xstrdup(real_path(git_dir));
+	char *real_work_tree = xstrdup(real_path(work_tree));
 
 	/* Update gitfile */
 	strbuf_addf(&file_name, "%s/.git", work_tree);
 	write_file(file_name.buf, "gitdir: %s",
-		   relative_path(git_dir, real_work_tree, &rel_path));
+		   relative_path(real_git_dir, real_work_tree, &rel_path));
 
 	/* Update core.worktree setting */
 	strbuf_reset(&file_name);
-	strbuf_addf(&file_name, "%s/config", git_dir);
+	strbuf_addf(&file_name, "%s/config", real_git_dir);
 	git_config_set_in_file(file_name.buf, "core.worktree",
-			       relative_path(real_work_tree, git_dir,
+			       relative_path(real_work_tree, real_git_dir,
 					     &rel_path));
 
 	strbuf_release(&file_name);
 	strbuf_release(&rel_path);
-	free((void *)real_work_tree);
+	free(real_work_tree);
+	free(real_git_dir);
 }
 
 int parallel_submodules(void)
-- 
2.11.0.rc2.18.g0126045.dirty