pull: fix handling of multiple heads
With multiple heads, we should not allow rebasing or fast-forwarding. Make sure any fast-forward request calls out specifically the fact that multiple branches are in play. Also, since we cannot fast-forward to multiple branches, fix our computation of can_ff. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Elijah Newren committed
Jul 22, 2021 at 05:04 UTC
6f843a3355ee590dfe09eb90679051e75fadf675
2 files changed
+15
-5
builtin/pull.c
+14
-4
@@ -913,12 +913,18 @@ static int run_rebase(const struct object_id *newbase,
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return ret;
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}
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-static int get_can_ff(struct object_id *orig_head, struct object_id *orig_merge_head)
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+static int get_can_ff(struct object_id *orig_head,
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+ struct oid_array *merge_heads)
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{
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int ret;
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struct commit_list *list = NULL;
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struct commit *merge_head, *head;
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+ struct object_id *orig_merge_head;
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+ if (merge_heads->nr > 1)
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+ return 0;
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+
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+ orig_merge_head = &merge_heads->oid[0];
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head = lookup_commit_reference(the_repository, orig_head);
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commit_list_insert(head, &list);
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merge_head = lookup_commit_reference(the_repository, orig_merge_head);
@@ -1057,10 +1063,14 @@ int cmd_pull(int argc, const char **argv, const char *prefix)
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die(_("Cannot merge multiple branches into empty head."));
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return pull_into_void(merge_heads.oid, &curr_head);
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}
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- if (opt_rebase && merge_heads.nr > 1)
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- die(_("Cannot rebase onto multiple branches."));
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+ if (merge_heads.nr > 1) {
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+ if (opt_rebase)
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+ die(_("Cannot rebase onto multiple branches."));
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+ if (opt_ff && !strcmp(opt_ff, "--ff-only"))
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+ die(_("Cannot fast-forward to multiple branches."));
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+ }
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- can_ff = get_can_ff(&orig_head, &merge_heads.oid[0]);
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+ can_ff = get_can_ff(&orig_head, &merge_heads);
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/* ff-only takes precedence over rebase */
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if (opt_ff && !strcmp(opt_ff, "--ff-only")) {
t/t7601-merge-pull-config.sh
+1
-1
@@ -331,7 +331,7 @@ test_expect_success 'Multiple heads warns about inability to fast forward' '
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test_i18ngrep "You have divergent branches" err
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'
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-test_expect_failure 'Multiple can never be fast forwarded' '
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+test_expect_success 'Multiple can never be fast forwarded' '
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git reset --hard c0 &&
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test_must_fail git -c pull.ff=only pull . c1 c2 c3 2>err &&
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test_i18ngrep ! "You have divergent branches" err &&