git-debrebase: convert-from-*: Snag on unused patches

Patches in d/patches which are not in series will be deleted, and not
represented in the output.

So call them a snag.

Closes:#904997.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

1 files changed, 22 insertions, 0 deletions

diff --git a/git-debrebase b/git-debrebase
index 5a9a9cb..66167b2 100755
--- a/git-debrebase
+++ b/git-debrebase
@@ -2390,6 +2390,24 @@ sub cmd_make_patches () {
     }
 }
 
+sub check_series_has_all_patches ($) {
+    my ($head) = @_;
+    my $seriesfn = 'debian/patches/series';
+    my ($dummy, $series) = git_cat_file "$head:$seriesfn",
+	[qw(blob missing)];
+    $series //= '';
+    my %series;
+    foreach my $f (grep /\S/, grep {!m/^\s\#/} split /\n/, $series) {
+	fail "patch $f repeated in $seriesfn !" if $series{$f}++;
+    }
+    foreach my $patchfile (get_tree "$head:debian/patches", 1,1) {
+	my ($f,$i) = @$patchfile;
+	next if $series{$f};
+	next if $f eq 'series';
+	snag 'unused-patches', "Unused patch file $f will be discarded";
+    }
+}
+
 sub cmd_convert_from_gbp () {
     badusage "want only 1 optional argument, the upstream git commitish"
 	unless @ARGV<=1;
@@ -2437,6 +2455,8 @@ END
 	    "upstream ($upstream) contains debian/ directory";
     }
 
+    check_series_has_all_patches $old_head;
+
     my $previous_dgit_view = eval {
 	my @clogcmd = qw(dpkg-parsechangelog --format rfc822 -n2);
 	my ($lvsn, $suite);
@@ -2587,6 +2607,8 @@ END
 	}
     }
 
+    check_series_has_all_patches $head;
+
     snags_maybe_bail_early();
 
     my $version = upstreamversion $clogp->{Version};