git-debrebase: Snag on repeated conversions

[dgit.git] / git-debrebase

diff --git a/git-debrebase b/git-debrebase
index 2e0882dfa6e2c9c70646d646c07db591e4c8b6e7..d80c8d35bb1875e509f658077eb3a1ed7cb7c69a 100755 (executable)
--- a/git-debrebase
+++ b/git-debrebase
@@ -428,9 +428,15 @@ sub any_snags () {
     return $snags_forced || $snags_tripped;
 }
 
-sub record_gdrlast ($$) {
-    my ($gdrlast, $newvalue) = @_;
-    push @deferred_updates, "update $gdrlast $newvalue $git_null_obj";
+sub ffq_prev_branchinfo () {
+    my $current = git_get_symref();
+    return gdr_ffq_prev_branchinfo($current);
+}
+
+sub record_gdrlast ($$;$) {
+    my ($gdrlast, $newvalue, $oldvalue) = @_;
+    $oldvalue ||= $git_null_obj;
+    push @deferred_updates, "update $gdrlast $newvalue $oldvalue";
 }
 
 sub gbp_pq_export ($$$) {
@@ -1740,11 +1746,6 @@ sub cmd_analyse () {
     STDOUT->error and die $!;
 }
 
-sub ffq_prev_branchinfo () {
-    my $current = git_get_symref();
-    return gdr_ffq_prev_branchinfo($current);
-}
-
 sub ffq_check ($;$$) {
     # calls $ff and/or $notff zero or more times
     # then returns either (status,message) where status is
@@ -2411,6 +2412,13 @@ sub check_series_has_all_patches ($) {
 
 sub begin_convert_from () {
     my $head = get_head();
+    my ($ffqs, $ffqm, $symref, $ffq_prev, $gdrlast) = ffq_prev_branchinfo();
+
+    fail "ffq-prev exists, this is already managed by git-debrebase!"
+       if $ffq_prev && git_get_ref $ffq_prev;
+    snag 'already-converted',
+       "ahead of debrebase-last, this is already managed by git-debrebase!"
+       if $gdrlast && git_get_ref $gdrlast && is_fast_fwd $gdrlast, $head;
     return ($head, undef);
 }