Merge branch 'jp/fetch-cull-many-refs'

* jp/fetch-cull-many-refs:
  remote: fix use-after-free error detected by glibc in ref_remove_duplicates
  fetch: Speed up fetch of large numbers of refs
  remote: Make ref_remove_duplicates faster for large numbers of refs

builtin-fetch.c

@@ -489,7 +489,8 @@ static int add_existing(const char *refname, const unsigned char *sha1,
 			int flag, void *cbdata)
 {
 	struct string_list *list = (struct string_list *)cbdata;
-	string_list_insert(refname, list);
+	struct string_list_item *item = string_list_insert(refname, list);
+	item->util = (void *)sha1;
 	return 0;
 }
 
@@ -615,9 +616,14 @@ static void check_not_current_branch(struct ref *ref_map)
 static int do_fetch(struct transport *transport,
 		    struct refspec *refs, int ref_count)
 {
+	struct string_list existing_refs = { NULL, 0, 0, 0 };
+	struct string_list_item *peer_item = NULL;
 	struct ref *ref_map;
 	struct ref *rm;
 	int autotags = (transport->remote->fetch_tags == 1);
+
+	for_each_ref(add_existing, &existing_refs);
+
 	if (transport->remote->fetch_tags == 2 && tags != TAGS_UNSET)
 		tags = TAGS_SET;
 	if (transport->remote->fetch_tags == -1)
@@ -640,8 +646,13 @@ static int do_fetch(struct transport *transport,
 		check_not_current_branch(ref_map);
 
 	for (rm = ref_map; rm; rm = rm->next) {
-		if (rm->peer_ref)
+		if (rm->peer_ref) {
-			read_ref(rm->peer_ref->name, rm->peer_ref->old_sha1);
+			peer_item = string_list_lookup(rm->peer_ref->name,
+						       &existing_refs);
+			if (peer_item)
+				hashcpy(rm->peer_ref->old_sha1,
+					peer_item->util);
+		}
 	}
 
 	if (tags == TAGS_DEFAULT && autotags)

remote.c

@@ -6,6 +6,7 @@
 #include "revision.h"
 #include "dir.h"
 #include "tag.h"
+#include "string-list.h"
 
 static struct refspec s_tag_refspec = {
 	0,
@@ -734,29 +735,33 @@ int for_each_remote(each_remote_fn fn, void *priv)
 
 void ref_remove_duplicates(struct ref *ref_map)
 {
-	struct ref **posn;
+	struct string_list refs = { NULL, 0, 0, 0 };
-	struct ref *next;
+	struct string_list_item *item = NULL;
-	for (; ref_map; ref_map = ref_map->next) {
+	struct ref *prev = NULL, *next = NULL;
+	for (; ref_map; prev = ref_map, ref_map = next) {
+		next = ref_map->next;
 		if (!ref_map->peer_ref)
 			continue;
-		posn = &ref_map->next;
+
-		while (*posn) {
+		item = string_list_lookup(ref_map->peer_ref->name, &refs);
-			if ((*posn)->peer_ref &&
+		if (item) {
-			    !strcmp((*posn)->peer_ref->name,
+			if (strcmp(((struct ref *)item->util)->name,
-				    ref_map->peer_ref->name)) {
+				   ref_map->name))
-				if (strcmp((*posn)->name, ref_map->name))
 				die("%s tracks both %s and %s",
 				    ref_map->peer_ref->name,
-					    (*posn)->name, ref_map->name);
+				    ((struct ref *)item->util)->name,
-				next = (*posn)->next;
+				    ref_map->name);
-				free((*posn)->peer_ref);
+			prev->next = ref_map->next;
-				free(*posn);
+			free(ref_map->peer_ref);
-				*posn = next;
+			free(ref_map);
-			} else {
+			ref_map = prev; /* skip this; we freed it */
-				posn = &(*posn)->next;
+			continue;
-			}
 		}
+
+		item = string_list_insert(ref_map->peer_ref->name, &refs);
+		item->util = ref_map;
 	}
+	string_list_clear(&refs, 0);
 }
 
 int remote_has_url(struct remote *remote, const char *url)

t/t5510-fetch.sh

@@ -341,4 +341,15 @@ test_expect_success 'fetch into the current branch with --update-head-ok' '
 
 '
 
+test_expect_success "should be able to fetch with duplicate refspecs" '
+        mkdir dups &&
+        cd dups &&
+        git init &&
+        git config branch.master.remote three &&
+        git config remote.three.url ../three/.git &&
+        git config remote.three.fetch +refs/heads/*:refs/remotes/origin/* &&
+        git config --add remote.three.fetch +refs/heads/*:refs/remotes/origin/* &&
+        git fetch three
+'
+
 test_done