fetch: verify we have everything we need before updating our ref

[git.git] / builtin / fetch.c

diff --git a/builtin/fetch.c b/builtin/fetch.c
index f9c41da475289b84fe849f7641406ebc94059630..bdb03ff54c51426f4c814dc7326e62b0bc3576c5 100644 (file)
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -345,6 +345,64 @@ static int update_local_ref(struct ref *ref,
        }
 }
 
+/*
+ * The ref_map records the tips of the refs we are fetching. If
+ *
+ *  $ git rev-list --verify-objects --stdin --not --all
+ *
+ * (feeding all the refs in ref_map on its standard input) does not
+ * error out, that means everything reachable from these updated refs
+ * locally exists and is connected to some of our existing refs.
+ *
+ * Returns 0 if everything is connected, non-zero otherwise.
+ */
+static int check_everything_connected(struct ref *ref_map, int quiet)
+{
+       struct child_process rev_list;
+       const char *argv[] = {"rev-list", "--verify-objects",
+                             "--stdin", "--not", "--all", NULL, NULL};
+       char commit[41];
+       struct ref *ref;
+       int err = 0;
+
+       if (!ref_map)
+               return 0;
+
+       if (quiet)
+               argv[5] = "--quiet";
+
+       memset(&rev_list, 0, sizeof(rev_list));
+       rev_list.argv = argv;
+       rev_list.git_cmd = 1;
+       rev_list.in = -1;
+       rev_list.no_stdout = 1;
+       rev_list.no_stderr = quiet;
+       if (start_command(&rev_list))
+               return error(_("Could not run 'git rev-list'"));
+
+       sigchain_push(SIGPIPE, SIG_IGN);
+
+       memcpy(commit + 40, "\n", 2);
+       for (ref = ref_map; ref; ref = ref->next) {
+               memcpy(commit, sha1_to_hex(ref->old_sha1), 40);
+               if (write_in_full(rev_list.in, commit, 41) < 0) {
+                       if (errno != EPIPE && errno != EINVAL)
+                               error(_("failed write to rev-list: %s"),
+                                     strerror(errno));
+                       err = -1;
+                       break;
+               }
+       }
+       if (close(rev_list.in)) {
+               error(_("failed to close rev-list's stdin: %s"), strerror(errno));
+               err = -1;
+       }
+
+       sigchain_pop(SIGPIPE);
+
+       return finish_command(&rev_list) || err;
+}
+
 static int store_updated_refs(const char *raw_url, const char *remote_name,
                struct ref *ref_map)
 {
@@ -364,6 +422,10 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
                url = transport_anonymize_url(raw_url);
        else
                url = xstrdup("foreign");
+
+       if (check_everything_connected(ref_map, 0))
+               return error(_("%s did not send all necessary objects\n"), url);
+
        for (rm = ref_map; rm; rm = rm->next) {
                struct ref *ref = NULL;
 
@@ -457,24 +519,9 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
  * We would want to bypass the object transfer altogether if
  * everything we are going to fetch already exists and is connected
  * locally.
- *
- * The refs we are going to fetch are in ref_map.  If running
- *
- *  $ git rev-list --objects --stdin --not --all
- *
- * (feeding all the refs in ref_map on its standard input)
- * does not error out, that means everything reachable from the
- * refs we are going to fetch exists and is connected to some of
- * our existing refs.
  */
 static int quickfetch(struct ref *ref_map)
 {
-       struct child_process revlist;
-       struct ref *ref;
-       int err;
-       const char *argv[] = {"rev-list",
-               "--quiet", "--objects", "--stdin", "--not", "--all", NULL};
-
        /*
         * If we are deepening a shallow clone we already have these
         * objects reachable.  Running rev-list here will return with
@@ -484,47 +531,7 @@ static int quickfetch(struct ref *ref_map)
         */
        if (depth)
                return -1;
-
-       if (!ref_map)
-               return 0;
-
-       memset(&revlist, 0, sizeof(revlist));
-       revlist.argv = argv;
-       revlist.git_cmd = 1;
-       revlist.no_stdout = 1;
-       revlist.no_stderr = 1;
-       revlist.in = -1;
-
-       err = start_command(&revlist);
-       if (err) {
-               error(_("could not run rev-list"));
-               return err;
-       }
-
-       /*
-        * If rev-list --stdin encounters an unknown commit, it terminates,
-        * which will cause SIGPIPE in the write loop below.
-        */
-       sigchain_push(SIGPIPE, SIG_IGN);
-
-       for (ref = ref_map; ref; ref = ref->next) {
-               if (write_in_full(revlist.in, sha1_to_hex(ref->old_sha1), 40) < 0 ||
-                   write_str_in_full(revlist.in, "\n") < 0) {
-                       if (errno != EPIPE && errno != EINVAL)
-                               error(_("failed write to rev-list: %s"), strerror(errno));
-                       err = -1;
-                       break;
-               }
-       }
-
-       if (close(revlist.in)) {
-               error(_("failed to close rev-list's stdin: %s"), strerror(errno));
-               err = -1;
-       }
-
-       sigchain_pop(SIGPIPE);
-
-       return finish_command(&revlist) || err;
+       return check_everything_connected(ref_map, 1);
 }
 
 static int fetch_refs(struct transport *transport, struct ref *ref_map)