From 40d2346f296559073578884ba0ba21cc7c28c94f Mon Sep 17 00:00:00 2001
From: epriestley <git@epriestley.com>
Date: Sat, 25 Apr 2020 09:16:53 -0700
Subject: [PATCH] Add a missing "null" check when rebuilding old/new diff
 content

Summary:
See <https://discourse.phabricator-community.org/t/exceptions-when-viewing-diffs/3787>. This list may include `null` values.

Until PHP 7.4, `$x = null; echo $x['y'];` does not emit a warning. Sneaky!

Test Plan:
  - Traced `null` values from `reparseHunksForSpecialAttributes()`, saw them no longer incorporated into corpus bodies.
  - This has some amount of test coverage.

Differential Revision: https://secure.phabricator.com/D21169
---
 .../differential/parser/DifferentialHunkParser.php           | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/applications/differential/parser/DifferentialHunkParser.php b/src/applications/differential/parser/DifferentialHunkParser.php
index 924789ca83..52f5bb90dc 100644
--- a/src/applications/differential/parser/DifferentialHunkParser.php
+++ b/src/applications/differential/parser/DifferentialHunkParser.php
@@ -456,6 +456,11 @@ final class DifferentialHunkParser extends Phobject {
 
     $corpus = array();
     foreach ($lines as $l) {
+      if ($l === null) {
+        $corpus[] = "\n";
+        continue;
+      }
+
       if ($l['type'] != '\\') {
         if ($l['text'] === null) {
           // There's no text on this side of the diff, but insert a placeholder