From 8b74ec543cd65112bd83f57dad5c7dcffb592224 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 6 Jan 2018 02:22:05 +0000
Subject: [PATCH] dgit: When source discrepancy involves mode changes, report
 them specially.

Closes:#886442.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 debian/changelog |  2 ++
 dgit             | 30 +++++++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/debian/changelog b/debian/changelog
index aa98a41a..591ee677 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -10,6 +10,8 @@ dgit (4.2~) experimental; urgency=medium
     Sean Whitton]  Closes:#856402.
 
   Minor fixes:
+  * When source discrepancy involves file mode changes, report them
+    specially.  Closes:#886442.
   * In split brain mode, with unexpected diffs, print dgit view
     commitid in suggested diff rune.  (HEAD is wrong.)  Closes:#886443.
   * Fix message about missing quilt cache entry to refer to
diff --git a/dgit b/dgit
index aa8f7717..2e51f76c 100755
--- a/dgit
+++ b/dgit
@@ -4240,7 +4240,35 @@ END
 	if ($r==256) {
 	    my $referent = $split_brain ? $dgithead : 'HEAD';
 	    my $diffs = cmdoutput @git, qw(diff --stat), $tree, $dgithead;
-	    fail <<END
+
+	    my @mode_changes;
+	    my $raw = cmdoutput @git,
+		qw(diff --no-renames -z -r --raw), $tree, $dgithead;
+	    my $changed;
+	    foreach (split /\0/, $raw) {
+		if (defined $changed) {
+		    push @mode_changes, "$changed: $_\n" if $changed;
+		    $changed = undef;
+		    next;
+		} elsif (m/^:0+ 0+ /) {
+		    $changed = '';
+		} elsif (m/^:(?:10*)?(\d+) (?:10*)?(\d+) /) {
+		    $changed = "Mode change from $1 to $2"
+		} else {
+		    die "$_ ?";
+		}
+	    }
+	    if (@mode_changes) {
+		fail <<END.(join '', @mode_changes).<<END;
+HEAD specifies a different tree to $dscfn:
+$diffs
+END
+There is a problem with your source tree (see dgit(7) for some hints).
+To see a full diff, run git diff $tree $referent
+END
+	    }
+
+	    fail <<END;
 HEAD specifies a different tree to $dscfn:
 $diffs
 Perhaps you forgot to build.  Or perhaps there is a problem with your
-- 
2.30.2