Re: [PATCH] Enable "git rerere" by the config variable rerere.enabled

Johannes Schindelin [off-list ref] writes:

Earlier, "git rerere" was enabled by creating the directory
.git/rr-cache.  That is definitely not in line with most other
features, which are enabled by a config variable.

So, check the config variable "rerere.enabled". If it is set
to "false" explicitely, do not activate rerere, even if
.git/rr-cache exists. This should help when you want to disable
rerere temporarily.

If "rerere.enabled" is not set at all, fall back to detection
of the directory .git/rr-cache.

Signed-off-by: Johannes Schindelin <redacted>
---

	Touches quite some parts, doesn't it?

	And yeah, the git-gui part should be factored out, I guess. Shawn?

I'll exclude git-gui part and commit with a minor tweaks; having
extra "does the directory exist" check in git-gui would not hurt
people who are used to how rerere works in the short term, and I
think I read somewhere that I should expect git-gui updates over
the weekend anyway.

-int cmd_rerere(int argc, const char **argv, const char *prefix)
+int is_rerere_enabled(void)
 {

This will be "static".

-	struct path_list merge_rr = { NULL, 0, 0, 1 };
-	int i, fd = -1;
 	struct stat st;
+	const char *rr_cache = git_path("rr-cache");
+	int rr_cache_exists;
 
-	if (stat(git_path("rr-cache"), &st) || !S_ISDIR(st.st_mode))
+	if (!rerere_enabled)
 		return 0;

As git_path() is not zero-cost, assignment to rr_cache will be
moved here.

 
+	rr_cache_exists = !stat(rr_cache, &st) && S_ISDIR(st.st_mode);
+	if (rerere_enabled < 0)
+		return rr_cache_exists;
+
+	if (!rr_cache_exists && (mkdir(rr_cache, 0777) ||
+			adjust_shared_perm(rr_cache)))
+		die("Could not create directory %s", rr_cache);
+	return 1;
+}

If rr-cache is a regular file, we will hit "Could not create
directory" which is exactly what we want anyway.  Even if it is
a dangling symlink, it would fail with "File exists", so that
should be Ok.