fetch: improve the error messages emitted for conflicting refspecs

If we find two refspecs that want to update the same local reference,
emit an error message that is more informative based on whether one of
the conflicting refspecs is an opportunistic update during a fetch
with explicit command-line refspecs.  And especially, do not die if an
opportunistic reference update conflicts with an express wish of the
user; rather, just emit a warning and skip the opportunistic reference
update.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/remote.c b/remote.c
index 0848faffa48b350465ff4aacda74641d1a0c921b..dc56619d23a0e8d04e118f4bab84fac2d31e290c 100644 (file)
--- a/remote.c
+++ b/remote.c
@@ -747,9 +747,28 @@ int for_each_remote(each_remote_fn fn, void *priv)
 
 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
 {
-       if (strcmp(ref1->name, ref2->name))
-               die(_("%s tracks both %s and %s"),
-                   ref2->peer_ref->name, ref1->name, ref2->name);
+       if (strcmp(ref1->name, ref2->name)) {
+               if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
+                   ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
+                       die(_("Cannot fetch both %s and %s to %s"),
+                           ref1->name, ref2->name, ref2->peer_ref->name);
+               } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
+                          ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
+                       warning(_("%s usually tracks %s, not %s"),
+                               ref2->peer_ref->name, ref2->name, ref1->name);
+               } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
+                          ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
+                       die(_("%s tracks both %s and %s"),
+                           ref2->peer_ref->name, ref1->name, ref2->name);
+               } else {
+                       /*
+                        * This last possibility doesn't occur because
+                        * FETCH_HEAD_IGNORE entries always appear at
+                        * the end of the list.
+                        */
+                       die(_("Internal error"));
+               }
+       }
        free(ref2->peer_ref);
        free(ref2);
 }

diff --git a/t/t5536-fetch-conflicts.sh b/t/t5536-fetch-conflicts.sh
index 679c53e044fad7a2651124eabc0620c2c94c7546..6c5d3a4ce0877b11bc7db530522447a65098979d 100755 (executable)
--- a/t/t5536-fetch-conflicts.sh
+++ b/t/t5536-fetch-conflicts.sh
@@ -22,7 +22,7 @@ verify_stderr () {
        cat >expected &&
        # We're not interested in the error
        # "fatal: The remote end hung up unexpectedly":
-       grep -v "hung up" <error >actual &&
+       grep -E '^(fatal|warning):' <error | grep -v 'hung up' >actual | sort &&
        test_cmp expected actual
 }
 
@@ -49,7 +49,7 @@ test_expect_success 'fetch conflict: config vs. config' '
                cd ccc &&
                test_must_fail git fetch origin 2>error &&
                verify_stderr <<-\EOF
-               fatal: refs/remotes/origin/branch1 tracks both refs/heads/branch1 and refs/heads/branch2
+               fatal: Cannot fetch both refs/heads/branch1 and refs/heads/branch2 to refs/remotes/origin/branch1
                EOF
        )
 '
@@ -78,18 +78,22 @@ test_expect_success 'fetch conflict: arg vs. arg' '
                        refs/heads/*:refs/remotes/origin/* \
                        refs/heads/branch2:refs/remotes/origin/branch1 2>error &&
                verify_stderr <<-\EOF
-               fatal: refs/remotes/origin/branch1 tracks both refs/heads/branch1 and refs/heads/branch2
+               fatal: Cannot fetch both refs/heads/branch1 and refs/heads/branch2 to refs/remotes/origin/branch1
                EOF
        )
 '
 
-test_expect_failure 'fetch conflict: criss-cross args' '
+test_expect_success 'fetch conflict: criss-cross args' '
        setup_repository xaa \
                "+refs/heads/*:refs/remotes/origin/*" && (
                cd xaa &&
                git fetch origin \
                        refs/heads/branch1:refs/remotes/origin/branch2 \
-                       refs/heads/branch2:refs/remotes/origin/branch1
+                       refs/heads/branch2:refs/remotes/origin/branch1 2>error &&
+               verify_stderr <<-\EOF
+               warning: refs/remotes/origin/branch1 usually tracks refs/heads/branch1, not refs/heads/branch2
+               warning: refs/remotes/origin/branch2 usually tracks refs/heads/branch2, not refs/heads/branch1
+               EOF
        )
 '