From d816479d7c4f57e2a7891de104d46732d2e3066c Mon Sep 17 00:00:00 2001
From: Byron Jones <bjones@mozilla.com>
Date: Wed, 30 Jan 2013 14:50:10 +0800
Subject: Bug 784352: show a warning when interdiff reports errors

---
 Bugzilla/Attachment/PatchReader.pm                 | 27 ++++++++++++++++++----
 .../en/default/attachment/diff-header.html.tmpl    | 19 ++++++++-------
 2 files changed, 33 insertions(+), 13 deletions(-)

diff --git a/Bugzilla/Attachment/PatchReader.pm b/Bugzilla/Attachment/PatchReader.pm
index a9df6e34e..800de0722 100644
--- a/Bugzilla/Attachment/PatchReader.pm
+++ b/Bugzilla/Attachment/PatchReader.pm
@@ -19,6 +19,9 @@ use strict;
 
 package Bugzilla::Attachment::PatchReader;
 
+use IPC::Open3;
+use Symbol 'gensym';
+
 use Bugzilla::Error;
 use Bugzilla::Attachment;
 use Bugzilla::Util;
@@ -109,8 +112,22 @@ sub process_interdiff {
     # Send through interdiff, send output directly to template.
     # Must hack path so that interdiff will work.
     $ENV{'PATH'} = $lc->{diffpath};
-    open my $interdiff_fh, "$lc->{interdiffbin} $old_filename $new_filename|";
-    binmode $interdiff_fh;
+
+    my ($interdiff_stdout, $interdiff_stderr);
+    $interdiff_stderr = gensym;
+    my $pid = open3(gensym, $interdiff_stdout, $interdiff_stderr,
+                    $lc->{interdiffbin}, $old_filename, $new_filename);
+    binmode $interdiff_stdout;
+
+    # Check for errors
+    {
+        local $/ = undef;
+        if (defined(my $error = <$interdiff_stderr>)) {
+            warn($error);
+            $warning = 'interdiff3';
+        }
+    }
+
     my ($reader, $last_reader) = setup_patch_readers("", $context);
 
     if ($format eq 'raw') {
@@ -123,7 +140,7 @@ sub process_interdiff {
     }
     else {
         # In case the HTML page is displayed with the UTF-8 encoding.
-        binmode $interdiff_fh, ':utf8' if Bugzilla->params->{'utf8'};
+        binmode $interdiff_stdout, ':utf8' if Bugzilla->params->{'utf8'};
 
         $vars->{'warning'} = $warning if $warning;
         $vars->{'bugid'} = $new_attachment->bug_id;
@@ -134,9 +151,9 @@ sub process_interdiff {
 
         setup_template_patch_reader($last_reader, $format, $context, $vars);
     }
-    $reader->iterate_fh($interdiff_fh, 'interdiff #' . $old_attachment->id .
+    $reader->iterate_fh($interdiff_stdout, 'interdiff #' . $old_attachment->id .
                         ' #' . $new_attachment->id);
-    close $interdiff_fh;
+    waitpid($pid, 0);
     $ENV{'PATH'} = '';
 
     # Delete temporary files.
diff --git a/template/en/default/attachment/diff-header.html.tmpl b/template/en/default/attachment/diff-header.html.tmpl
index c13b2e7ba..8cb5525f7 100644
--- a/template/en/default/attachment/diff-header.html.tmpl
+++ b/template/en/default/attachment/diff-header.html.tmpl
@@ -133,15 +133,18 @@ Interdiff of #[% oldid %] and #[% newid %] for [% terms.bug %] #[% bugid %]
 [% END %]
 
 [% IF warning %]
-<h2 class="warning">Warning: 
+<h2 class="warning">
+  Warning:
   [% IF warning == "interdiff1" %]
-  this difference between two patches may show things in the wrong places due
-  to a limitation in [% terms.Bugzilla %] when comparing patches with different
-  sets of files.
-  [% END %]
-  [% IF warning == "interdiff2" %]
-  this difference between two patches may be inaccurate due to a limitation in
-  [%+ terms.Bugzilla %] when comparing patches made against different revisions.
+    this difference between two patches may show things in the wrong places due
+    to a limitation in [% terms.Bugzilla %] when comparing patches with
+    different sets of files.
+  [% ELSIF warning == "interdiff2" %]
+    this difference between two patches may be inaccurate due to a limitation
+    in [%+ terms.Bugzilla %] when comparing patches made against different
+    revisions.
+  [% ELSIF warning == "interdiff3" %]
+    interdiff encountered errors while comparing these patches.
   [% END %]
 </h2>
 [% ELSE %]
-- 
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