[PATCH v2] remote: make prune work for mixed mirror/non-mirror repos

[Dennis Kaarsemaker <dennis@kaarsemaker.net>]

When cloning a repo with --mirror, and adding more remotes later,
get_stale_heads for origin would mark all refs from other repos as stale. In
this situation, with refs-src and refs->dst both equal to refs/*, we should
ignore refs/remotes/* and refs/tags/* when looking for stale refs to
prevent this from happening.

Signed-off-by: Dennis Kaarsemaker <dennis@kaarsemaker.net>
---
 The previous attempt only ignored refs/remotes, but that's not good enough as
 that will still delete tags. So let's ignore refs/tags too. The downside is
 that tags removed at the origin don't get removed, but prune should only be
 pruning branches anyway if I read the documentation correctly.

 remote.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/remote.c b/remote.c
index e71f66d..efc5481 100644
--- a/remote.c
+++ b/remote.c
@@ -1884,6 +1884,7 @@ struct stale_heads_info {
 	struct ref **stale_refs_tail;
 	struct refspec *refs;
 	int ref_count;
+	int is_mirror;
 };
 
 static int get_stale_heads_cb(const char *refname,
@@ -1896,6 +1897,13 @@ static int get_stale_heads_cb(const char *refname,
 
 	if (query_refspecs(info->refs, info->ref_count, &query))
 		return 0; /* No matches */
+	/*
+	 * If we're pruning a clone that was --mirror'ed, let's ignore refs/tags
+	 * and refs/remotes
+	 */
+	if (info->is_mirror && (!prefixcmp(refname, "refs/tags/") ||
+	    !prefixcmp(refname, "refs/remotes/")))
+		return 0;
 
 	/*
 	 * If we did find a suitable refspec and it's not a symref and
@@ -1917,6 +1925,8 @@ struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fet
 	struct ref *ref, *stale_refs = NULL;
 	struct string_list ref_names = STRING_LIST_INIT_NODUP;
 	struct stale_heads_info info;
+	if(!strcmp(refs->src, "refs/*") && !strcmp(refs->dst, "refs/*"))
+		info.is_mirror = 1;
 	info.ref_names = &ref_names;
 	info.stale_refs_tail = &stale_refs;
 	info.refs = refs;
-- 
1.8.3.1-619-gbec0aa7