Index: ps/trunk/build/arclint/pyrolint/__phutil_library_map__.php
===================================================================
--- ps/trunk/build/arclint/pyrolint/__phutil_library_map__.php
+++ ps/trunk/build/arclint/pyrolint/__phutil_library_map__.php
@@ -10,11 +10,13 @@
   '__library_version__' => 2,
   'class' => array(
     'ESLintLinter' => 'src/ESLintLinter.php',
+    'JenkinsRenderer' => 'src/JenkinsRenderer.php',
     'LicenceYearLinter' => 'src/LicenceYearLinter.php',
   ),
   'function' => array(),
   'xmap' => array(
     'ESLintLinter' => 'ArcanistExternalLinter',
+    'JenkinsRenderer' => 'ArcanistLintRenderer',
     'LicenceYearLinter' => 'ArcanistLinter',
   ),
 ));
Index: ps/trunk/build/arclint/pyrolint/src/JenkinsRenderer.php
===================================================================
--- ps/trunk/build/arclint/pyrolint/src/JenkinsRenderer.php
+++ ps/trunk/build/arclint/pyrolint/src/JenkinsRenderer.php
@@ -0,0 +1,49 @@
+<?php
+/**
+ * Copyright 2021 Wildfire Games.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * The phabricator-jenkins-plugin expects a lint format
+ * that isn't quite compatible with `arc lint --output json`.
+ * This adds a custom output style `jenkins` that is.
+ * It's heavily based on Arcanist's regular JSON renderer.
+ * See https://github.com/uber/phabricator-jenkins-plugin/issues/255.
+ * The expected format is one line per message, as a dictionary.
+ */
+
+final class JenkinsRenderer extends ArcanistLintRenderer {
+
+  const RENDERERKEY = 'jenkins';
+
+  const LINES_OF_CONTEXT = 3;
+
+  public function renderLintResult(ArcanistLintResult $result) {
+    $messages = $result->getMessages();
+    $path = $result->getPath();
+    $data = explode("\n", $result->getData());
+    array_unshift($data, ''); // make the line numbers work as array indices
+
+    foreach ($messages as $message) {
+      $dictionary = $message->toDictionary();
+      $dictionary['context'] = implode("\n", array_slice(
+        $data,
+        max(1, $message->getLine() - self::LINES_OF_CONTEXT),
+        self::LINES_OF_CONTEXT * 2 + 1));
+      $dictionary['path'] = $path;
+      $this->writeOut(json_encode(json_decode(json_encode($dictionary)))."\n");
+    }
+  }
+}
Index: ps/trunk/build/jenkins/pipelines/docker-differential.Jenkinsfile
===================================================================
--- ps/trunk/build/jenkins/pipelines/docker-differential.Jenkinsfile
+++ ps/trunk/build/jenkins/pipelines/docker-differential.Jenkinsfile
@@ -133,8 +133,8 @@
 						sh '''
 						for file in builderr-*.txt ; do
 						  if [ -s "$file" ]; then
-						    echo "$file" >> build-errors.txt
-						    cat "$file" >> build-errors.txt
+							echo "$file" >> build-errors.txt
+							cat "$file" >> build-errors.txt
 						  fi
 						done
 						'''
@@ -147,9 +147,14 @@
 			steps {
 				script {
 					try {
-						sh 'arc lint --output json > .phabricator-lint'
+						// arc lint outputs an empty file on success - unless there is nothing to lint.
+						// On failure, it'll output the file and a failure error code.
+						// Explicitly checking for the file presence is thus best to detect the linter did run
+						sh 'arc lint --output jenkins --outfile .phabricator-lint && touch .phabricator-lint'
 					} catch (e) {
-						sh 'echo \"{ \\\"name\\\": \\\"error\\\", \\\"severity\\\": \\\"error\\\", \\\"code\\\": \\\"0\\\", \\\"description\\\": \\\"lint could not run\\\" }\" > .phabricator-lint '
+						if (!fileExists(".phabricator-lint")) {
+							sh '''echo '{ "path": "general", code": "Jenkins", "severity": "error", "name": "ci-error", "description": "Error running lint", "bypassChangedLineFiltering": true }' > .phabricator-lint '''
+						}
 					}
 				}
 			}