diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index fde804593b..8c2d9b8eef 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -2339,12 +2339,14 @@ sub format_extended_diff_header_line {
 		$line .= $cgi->a({-href=>$to->{'href'}, -class=>"path"},
 		                 esc_path($to->{'file'}));
 	}
-	# match single <mode>
-	if ($line =~ m/\s(\d{6})$/) {
-		$line .= '<span class="info"> (' .
-		         file_type_long($1) .
-		         ')</span>';
+
+	# Temporarily remove a trailing <mode> so an index line ends with its
+	# object IDs and can be shortened below.
+	my $mode;
+	if ($line =~ s/\s(\d{6})$//) {
+		$mode = $1;
 	}
+
 	# match <hash>
 	if ($line =~ oid_nlen_prefix_infix_regex($sha1_len, "index ", ",") |
 	    $line =~ oid_nlen_prefix_infix_regex($sha256_len, "index ", ",")) {
@@ -2388,6 +2390,12 @@ sub format_extended_diff_header_line {
 		my ($from_id, $to_id) = ($diffinfo->{'from_id'}, $diffinfo->{'to_id'});
 		$line =~ s!$from_id\.\.$to_id!$from_link..$to_link!;
 	}
+	if (defined $mode) {
+		$line .= " $mode" .
+		         '<span class="info"> (' .
+		         file_type_long($mode) .
+		         ')</span>';
+	}
 
 	return $line . "<br/>\n";
 }
diff --git a/t/t9502-gitweb-standalone-parse-output.sh b/t/t9502-gitweb-standalone-parse-output.sh
index 9587ce212a..00cf077e52 100755
--- a/t/t9502-gitweb-standalone-parse-output.sh
+++ b/t/t9502-gitweb-standalone-parse-output.sh
@@ -115,6 +115,19 @@ test_expect_success 'snapshot: hierarchical branch name (xx/test)' '
 '
 test_debug 'cat gitweb.headers'
 
+test_expect_success 'commitdiff: index line shortens hashes with mode' '
+	old_blob=$(git rev-parse HEAD:foo) &&
+	old_short=$(git rev-parse --short=7 HEAD:foo) &&
+	echo changed >foo &&
+	git commit -am "change foo" &&
+	new_blob=$(git rev-parse HEAD:foo) &&
+	new_short=$(git rev-parse --short=7 HEAD:foo) &&
+	gitweb_run "p=.git;a=commitdiff;h=HEAD" &&
+	test_grep ">${old_short}</a>\\.\\.<a [^>]*>${new_short}</a> 100644<span class=\"info\"> (file)</span>" \
+		gitweb.body &&
+	test_grep ! "index ${old_blob}\\.\\.${new_blob} 100644" gitweb.body
+'
+
 # ----------------------------------------------------------------------
 # forks of projects