Re: [PATCHv8 6/6] submodule: add absorb-git-dir function

On Tue, Dec 20, 2016 at 1:15 AM, Stefan Beller [off-list ref] wrote:

On Sun, Dec 18, 2016 at 9:35 PM, Duy Nguyen [off-list ref] wrote:

quoted

On Mon, Dec 12, 2016 at 11:04:35AM -0800, Stefan Beller wrote:

quoted

diff --git a/dir.c b/dir.c
index e0efd3c2c3..d872cc1570 100644
--- a/dir.c
+++ b/dir.c

@@ -2773,3 +2773,15 @@ void connect_work_tree_and_git_dir(const char *work_tree_, const char *git_dir_)
      free(work_tree);
      free(git_dir);
 }
+
+/*
+ * Migrate the git directory of the given path from old_git_dir to new_git_dir.
+ */
+void relocate_gitdir(const char *path, const char *old_git_dir, const char *new_git_dir)
+{
+     if (rename(old_git_dir, new_git_dir) < 0)
+             die_errno(_("could not migrate git directory from '%s' to '%s'"),
+                     old_git_dir, new_git_dir);
+
+     connect_work_tree_and_git_dir(path, new_git_dir);

Should we worry about recovering (e.g. maybe move new_git_dir back to
old_git_dir) if this connect_work_tree_and_git_dir() fails?

What if the move back fails?

That's when you pray the UNIX gods that recovery steps don't fail :-)
This is why I don't _suggest_ to do things but just wonder about it.
In theory though, if we keep recovery to dead simple operations (e.g.
a series of rename() and nothing else) then it's less likely to fail.
I'll look at the new patches when I get home.
-- 
Duy