1 files changed, 46 insertions, 0 deletions
diff --git a/third_party/gerrit/0003-Syntax-highlight-rules.pl.patch b/third_party/gerrit/0003-Syntax-highlight-rules.pl.patch
new file mode 100644
index 0000000000..02bb3397ea
--- /dev/null
+++ b/third_party/gerrit/0003-Syntax-highlight-rules.pl.patch
@@ -0,0 +1,46 @@
+From be348f64eda257ae0af1f89552548d3e8eca3688 Mon Sep 17 00:00:00 2001
+From: Luke Granger-Brown <git@lukegb.com>
+Date: Thu, 2 Jul 2020 23:02:43 +0100
+Subject: [PATCH 3/7] Syntax highlight rules.pl
+
+---
+ .../diff/gr-syntax-layer/gr-syntax-layer.ts         | 13 ++++++++++++-
+ 1 file changed, 12 insertions(+), 1 deletion(-)
+
+diff --git a/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts b/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
+index 2762ccc625..598e14589f 100644
+--- a/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
++++ b/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
+@@ -103,6 +103,10 @@ const LANGUAGE_MAP = new Map<string, string>([
+ ]);
+ const ASYNC_DELAY = 10;
+ 
++const FILENAME_OVERRIDES = new Map<string, string>([
++  ['rules.pl', 'prolog'],
++]);
++
+ const CLASS_SAFELIST = new Set<string>([
+   'gr-diff gr-syntax gr-syntax-attr',
+   'gr-diff gr-syntax gr-syntax-attribute',
+@@ -241,10 +245,17 @@ export class GrSyntaxLayer implements DiffLayer {
+     }
+   }
+ 
++  _basename(filename: string): string {
++    const pieces = filename.split(/\//);
++    return pieces[pieces.length-1];
++  }
++
+   _getLanguage(metaInfo: DiffFileMetaInfo) {
+     // The Gerrit API provides only content-type, but for other users of
+     // gr-diff it may be more convenient to specify the language directly.
+-    return metaInfo.language ?? LANGUAGE_MAP.get(metaInfo.content_type);
++    return metaInfo.language ??
++        FILENAME_OVERRIDES.get(this._basename(metaInfo.name)) ??
++        LANGUAGE_MAP.get(metaInfo.content_type);
+   }
+ 
+   /**
+-- 
+2.32.0
+