diff --git a/src/lint/renderer/ArcanistCheckstyleXMLLintRenderer.php b/src/lint/renderer/ArcanistCheckstyleXMLLintRenderer.php
index 32091bf5..7e43ec10 100644
--- a/src/lint/renderer/ArcanistCheckstyleXMLLintRenderer.php
+++ b/src/lint/renderer/ArcanistCheckstyleXMLLintRenderer.php
@@ -1,70 +1,65 @@
 <?php
 
-/**
- * Shows lint messages to the user.
- */
 final class ArcanistCheckstyleXMLLintRenderer extends ArcanistLintRenderer {
 
+  const RENDERERKEY = 'xml';
+
   private $writer;
 
   public function __construct() {
     $this->writer = new XMLWriter();
     $this->writer->openMemory();
     $this->writer->setIndent(true);
     $this->writer->setIndentString('  ');
   }
 
-  public function renderPreamble() {
+  public function willRenderResults() {
     $this->writer->startDocument('1.0', 'UTF-8');
     $this->writer->startElement('checkstyle');
     $this->writer->writeAttribute('version', '4.3');
-    return $this->writer->flush();
+    $this->writeOut($this->writer->flush());
   }
 
   public function renderLintResult(ArcanistLintResult $result) {
     $this->writer->startElement('file');
     $this->writer->writeAttribute('name', $result->getPath());
 
     foreach ($result->getMessages() as $message) {
       $this->writer->startElement('error');
 
       $this->writer->writeAttribute('line', $message->getLine());
       $this->writer->writeAttribute('column', $message->getChar());
       $this->writer->writeAttribute('severity',
         $this->getStringForSeverity($message->getSeverity()));
       $this->writer->writeAttribute('message', $message->getDescription());
       $this->writer->writeAttribute('source', $message->getCode());
 
       $this->writer->endElement();
     }
 
     $this->writer->endElement();
-    return $this->writer->flush();
-  }
-
-  public function renderOkayResult() {
-    return '';
+    $this->writeOut($this->writer->flush());
   }
 
-  public function renderPostamble() {
+  public function didRenderResults() {
     $this->writer->endElement();
     $this->writer->endDocument();
-    return $this->writer->flush();
+    $this->writeOut($this->writer->flush());
   }
 
   private function getStringForSeverity($severity) {
     switch ($severity) {
       case ArcanistLintSeverity::SEVERITY_ADVICE:
         return 'info';
       case ArcanistLintSeverity::SEVERITY_AUTOFIX:
         return 'info';
       case ArcanistLintSeverity::SEVERITY_WARNING:
         return 'warning';
       case ArcanistLintSeverity::SEVERITY_ERROR:
         return 'error';
       case ArcanistLintSeverity::SEVERITY_DISABLED:
         return 'ignore';
     }
   }
 
 }
diff --git a/src/lint/renderer/ArcanistCompilerLintRenderer.php b/src/lint/renderer/ArcanistCompilerLintRenderer.php
index 264750b1..947274d4 100644
--- a/src/lint/renderer/ArcanistCompilerLintRenderer.php
+++ b/src/lint/renderer/ArcanistCompilerLintRenderer.php
@@ -1,35 +1,30 @@
 <?php
 
-/**
- * Shows lint messages to the user.
- */
 final class ArcanistCompilerLintRenderer extends ArcanistLintRenderer {
 
+  const RENDERERKEY = 'compiler';
+
   public function renderLintResult(ArcanistLintResult $result) {
     $lines = array();
     $messages = $result->getMessages();
     $path = $result->getPath();
 
     foreach ($messages as $message) {
       $severity = ArcanistLintSeverity::getStringForSeverity(
         $message->getSeverity());
       $line = $message->getLine();
       $code = $message->getCode();
       $description = $message->getDescription();
       $lines[] = sprintf(
         "%s:%d:%s (%s) %s\n",
         $path,
         $line,
         $severity,
         $code,
         $description);
     }
 
-    return implode('', $lines);
-  }
-
-  public function renderOkayResult() {
-    return '';
+    $this->writeOut(implode('', $lines));
   }
 
 }
diff --git a/src/lint/renderer/ArcanistConsoleLintRenderer.php b/src/lint/renderer/ArcanistConsoleLintRenderer.php
index ea233e3d..fb90b590 100644
--- a/src/lint/renderer/ArcanistConsoleLintRenderer.php
+++ b/src/lint/renderer/ArcanistConsoleLintRenderer.php
@@ -1,312 +1,324 @@
 <?php
 
-/**
- * Shows lint messages to the user.
- */
 final class ArcanistConsoleLintRenderer extends ArcanistLintRenderer {
 
-  private $showAutofixPatches = false;
-  private $testableMode;
+  const RENDERERKEY = 'console';
 
-  public function setShowAutofixPatches($show_autofix_patches) {
-    $this->showAutofixPatches = $show_autofix_patches;
-    return $this;
-  }
+  private $testableMode;
 
   public function setTestableMode($testable_mode) {
     $this->testableMode = $testable_mode;
     return $this;
   }
 
   public function getTestableMode() {
     return $this->testableMode;
   }
 
+  public function supportsPatching() {
+    return true;
+  }
+
+  public function renderResultCode($result_code) {
+    if ($result_code == ArcanistLintWorkflow::RESULT_OKAY) {
+      $view = new PhutilConsoleInfo(
+        pht('OKAY'),
+        pht('No lint messages.'));
+      $this->writeOut($view->drawConsoleString());
+    }
+  }
+
+  public function promptForPatch(
+    ArcanistLintResult $result,
+    $old_path,
+    $new_path) {
+
+    if ($old_path === null) {
+      $old_path = '/dev/null';
+    }
+
+    list($err, $stdout) = exec_manual('diff -u %s %s', $old_path, $new_path);
+    $this->writeOut($stdout);
+
+    $prompt = pht(
+      'Apply this patch to %s?',
+      tsprintf('__%s__', $result->getPath()));
+
+    return phutil_console_confirm($prompt, $default_no = false);
+  }
+
   public function renderLintResult(ArcanistLintResult $result) {
     $messages = $result->getMessages();
     $path = $result->getPath();
     $data = $result->getData();
 
     $line_map = $this->newOffsetMap($data);
 
     $text = array();
     foreach ($messages as $message) {
-      if (!$this->showAutofixPatches && $message->isAutofix()) {
-        continue;
-      }
-
       if ($message->isError()) {
         $color = 'red';
       } else {
         $color = 'yellow';
       }
 
       $severity = ArcanistLintSeverity::getStringForSeverity(
         $message->getSeverity());
       $code = $message->getCode();
       $name = $message->getName();
       $description = $message->getDescription();
 
       if ($message->getOtherLocations()) {
         $locations = array();
         foreach ($message->getOtherLocations() as $location) {
           $locations[] =
             idx($location, 'path', $path).
             (!empty($location['line']) ? ":{$location['line']}" : '');
         }
         $description .= "\n".pht(
           'Other locations: %s',
           implode(', ', $locations));
       }
 
       $text[] = phutil_console_format(
         "  **<bg:{$color}> %s </bg>** (%s) __%s__\n%s\n",
         $severity,
         $code,
         $name,
         phutil_console_wrap($description, 4));
 
       if ($message->hasFileContext()) {
         $text[] = $this->renderContext($message, $data, $line_map);
       }
     }
 
     if ($text) {
       $prefix = phutil_console_format(
         "**>>>** %s\n\n\n",
         pht(
           'Lint for %s:',
           phutil_console_format('__%s__', $path)));
-      return $prefix.implode("\n", $text);
-    } else {
-      return null;
+      $this->writeOut($prefix.implode("\n", $text));
     }
   }
 
   protected function renderContext(
     ArcanistLintMessage $message,
     $data,
     array $line_map) {
 
     $context = 3;
 
     $message = $message->newTrimmedMessage();
 
     $original = $message->getOriginalText();
     $replacement = $message->getReplacementText();
 
     $line = $message->getLine();
     $char = $message->getChar();
 
     $old = $data;
     $old_lines = phutil_split_lines($old);
     $old_impact = substr_count($original, "\n") + 1;
     $start = $line;
 
     if ($message->isPatchable()) {
       $patch_offset = $line_map[$line] + ($char - 1);
 
       $new = substr_replace(
         $old,
         $replacement,
         $patch_offset,
         strlen($original));
       $new_lines = phutil_split_lines($new);
 
       // Figure out how many "-" and "+" lines we have by counting the newlines
       // for the relevant patches. This may overestimate things if we are adding
       // or removing entire lines, but we'll adjust things below.
       $new_impact = substr_count($replacement, "\n") + 1;
 
       // If this is a change on a single line, we'll try to highlight the
       // changed character range to make it easier to pick out.
       if ($old_impact === 1 && $new_impact === 1) {
         $old_lines[$start - 1] = substr_replace(
           $old_lines[$start - 1],
           $this->highlightText($original),
           $char - 1,
           strlen($original));
 
         $new_lines[$start - 1] = substr_replace(
           $new_lines[$start - 1],
           $this->highlightText($replacement),
           $char - 1,
           strlen($replacement));
       }
 
       // If lines at the beginning of the changed line range are actually the
       // same, shrink the range. This happens when a patch just adds a line.
       do {
         $old_line = idx($old_lines, $start - 1, null);
         $new_line = idx($new_lines, $start - 1, null);
 
         if ($old_line !== $new_line) {
           break;
         }
 
         $start++;
         $old_impact--;
         $new_impact--;
 
         if ($old_impact < 0 || $new_impact < 0) {
           throw new Exception(
             pht(
               'Modified prefix line range has become negative '.
               '(old = %d, new = %d).',
               $old_impact,
               $new_impact));
         }
       } while (true);
 
       // If the lines at the end of the changed line range are actually the
       // same, shrink the range. This happens when a patch just removes a
       // line.
       do {
         $old_suffix = idx($old_lines, $start + $old_impact - 2, null);
         $new_suffix = idx($new_lines, $start + $new_impact - 2, null);
 
         if ($old_suffix !== $new_suffix) {
           break;
         }
 
         $old_impact--;
         $new_impact--;
 
         // We can end up here if a patch removes a line which occurs after
         // another identical line.
         if ($old_impact <= 0 || $new_impact <= 0) {
           break;
         }
       } while (true);
 
     } else {
 
       // If we have "original" text and it is contained on a single line,
       // highlight the affected area. If we don't have any text, we'll mark
       // the character with a caret (below, in rendering) instead.
       if ($old_impact == 1 && strlen($original)) {
         $old_lines[$start - 1] = substr_replace(
           $old_lines[$start - 1],
           $this->highlightText($original),
           $char - 1,
           strlen($original));
       }
 
       $old_impact = 0;
       $new_impact = 0;
     }
 
     $out = array();
 
     $head = max(1, $start - $context);
     for ($ii = $head; $ii < $start; $ii++) {
       $out[] = array(
         'text' => $old_lines[$ii - 1],
         'number' => $ii,
       );
     }
 
     for ($ii = $start; $ii < $start + $old_impact; $ii++) {
       $out[] = array(
         'text' => $old_lines[$ii - 1],
         'number' => $ii,
         'type' => '-',
         'chevron' => ($ii == $start),
       );
     }
 
     for ($ii = $start; $ii < $start + $new_impact; $ii++) {
       $out[] = array(
         'text' => $new_lines[$ii - 1],
         'type' => '+',
         'chevron' => ($ii == $start),
       );
     }
 
     $cursor = $start + $old_impact;
     $foot = min(count($old_lines), $cursor + $context);
     for ($ii = $cursor; $ii <= $foot; $ii++) {
       $out[] = array(
         'text' => $old_lines[$ii - 1],
         'number' => $ii,
         'chevron' => ($ii == $cursor),
       );
     }
 
     $result = array();
 
     $seen_chevron = false;
     foreach ($out as $spec) {
       if ($seen_chevron) {
         $chevron = false;
       } else {
         $chevron = !empty($spec['chevron']);
         if ($chevron) {
           $seen_chevron = true;
         }
       }
 
       $result[] = $this->renderLine(
         idx($spec, 'number'),
         $spec['text'],
         $chevron,
         idx($spec, 'type'));
 
       // If this is just a message and does not have a patch, put a little
       // caret underneath the line to point out where the issue is.
       if ($chevron) {
         if (!$message->isPatchable() && !strlen($original)) {
           $result[] = $this->renderCaret($char)."\n";
         }
       }
     }
 
     return implode('', $result);
   }
 
   private function renderCaret($pos) {
     return str_repeat(' ', 16 + $pos).'^';
   }
 
   protected function renderLine($line, $data, $chevron = false, $diff = null) {
     $chevron = $chevron ? '>>>' : '';
     return sprintf(
       '    %3s %1s %6s %s',
       $chevron,
       $diff,
       $line,
       $data);
   }
 
-  public function renderOkayResult() {
-    return phutil_console_format(
-      "<bg:green>** %s **</bg> %s\n",
-      pht('OKAY'),
-      pht('No lint warnings.'));
-  }
-
   private function newOffsetMap($data) {
     $lines = phutil_split_lines($data);
 
     $line_map = array();
 
     $number = 1;
     $offset = 0;
     foreach ($lines as $line) {
       $line_map[$number] = $offset;
       $number++;
       $offset += strlen($line);
     }
 
     return $line_map;
   }
 
   private function highlightText($text) {
     if ($this->getTestableMode()) {
       return '>'.$text.'<';
     } else {
       return (string)tsprintf('##%s##', $text);
     }
   }
 
 }
diff --git a/src/lint/renderer/ArcanistJSONLintRenderer.php b/src/lint/renderer/ArcanistJSONLintRenderer.php
index 04432344..034ade8d 100644
--- a/src/lint/renderer/ArcanistJSONLintRenderer.php
+++ b/src/lint/renderer/ArcanistJSONLintRenderer.php
@@ -1,35 +1,30 @@
 <?php
 
-/**
- * Shows lint messages to the user.
- */
 final class ArcanistJSONLintRenderer extends ArcanistLintRenderer {
 
+  const RENDERERKEY = 'json';
+
   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
 
     $output = array($path => array());
 
     foreach ($messages as $message) {
       $dictionary = $message->toDictionary();
       $dictionary['context'] = implode("\n", array_slice(
         $data,
         max(1, $message->getLine() - self::LINES_OF_CONTEXT),
         self::LINES_OF_CONTEXT * 2 + 1));
       unset($dictionary['path']);
       $output[$path][] = $dictionary;
     }
 
-    return json_encode($output)."\n";
-  }
-
-  public function renderOkayResult() {
-    return '';
+    $this->writeOut(json_encode($output)."\n");
   }
 
 }
diff --git a/src/lint/renderer/ArcanistLintRenderer.php b/src/lint/renderer/ArcanistLintRenderer.php
index f153967d..1999fa6f 100644
--- a/src/lint/renderer/ArcanistLintRenderer.php
+++ b/src/lint/renderer/ArcanistLintRenderer.php
@@ -1,19 +1,61 @@
 <?php
 
-/**
- * Shows lint messages to the user.
- */
 abstract class ArcanistLintRenderer extends Phobject {
 
-  public function renderPreamble() {
-    return '';
+  private $output;
+
+  final public function getRendererKey() {
+    return $this->getPhobjectClassConstant('RENDERERKEY');
+  }
+
+  final public static function getAllRenderers() {
+    return id(new PhutilClassMapQuery())
+      ->setAncestorClass(__CLASS__)
+      ->setUniqueMethod('getRendererKey')
+      ->execute();
+  }
+
+  final public function setOutputPath($path) {
+    $this->output = $path;
+    return $this;
+  }
+
+
+  /**
+   * Does this renderer support applying lint patches?
+   *
+   * @return bool True if patches should be applied when using this renderer.
+   */
+  public function supportsPatching() {
+    return false;
+  }
+
+  public function willRenderResults() {
+    return null;
+  }
+
+  public function didRenderResults() {
+    return null;
+  }
+
+  public function renderResultCode($result_code) {
+    return null;
+  }
+
+  public function handleException(Exception $ex) {
+    throw $ex;
   }
 
   abstract public function renderLintResult(ArcanistLintResult $result);
-  abstract public function renderOkayResult();
 
-  public function renderPostamble() {
-    return '';
+  protected function writeOut($message) {
+    if ($this->output) {
+      Filesystem::appendFile($this->output, $message);
+    } else {
+      echo $message;
+    }
+
+    return $this;
   }
 
 }
diff --git a/src/lint/renderer/ArcanistNoneLintRenderer.php b/src/lint/renderer/ArcanistNoneLintRenderer.php
index ce74e395..c28e2cb0 100644
--- a/src/lint/renderer/ArcanistNoneLintRenderer.php
+++ b/src/lint/renderer/ArcanistNoneLintRenderer.php
@@ -1,13 +1,11 @@
 <?php
 
 final class ArcanistNoneLintRenderer extends ArcanistLintRenderer {
 
-  public function renderLintResult(ArcanistLintResult $result) {
-    return '';
-  }
+  const RENDERERKEY = 'none';
 
-  public function renderOkayResult() {
-    return '';
+  public function renderLintResult(ArcanistLintResult $result) {
+    return null;
   }
 
 }
diff --git a/src/lint/renderer/ArcanistSummaryLintRenderer.php b/src/lint/renderer/ArcanistSummaryLintRenderer.php
index 92eed3a4..22c6aba0 100644
--- a/src/lint/renderer/ArcanistSummaryLintRenderer.php
+++ b/src/lint/renderer/ArcanistSummaryLintRenderer.php
@@ -1,32 +1,33 @@
 <?php
 
-/**
- * Shows lint messages to the user.
- */
 final class ArcanistSummaryLintRenderer extends ArcanistLintRenderer {
 
+  const RENDERERKEY = 'summary';
+
   public function renderLintResult(ArcanistLintResult $result) {
     $messages = $result->getMessages();
     $path = $result->getPath();
 
     $text = array();
     foreach ($messages as $message) {
       $name = $message->getName();
       $severity = ArcanistLintSeverity::getStringForSeverity(
         $message->getSeverity());
       $line = $message->getLine();
 
       $text[] = "{$path}:{$line}:{$severity}: {$name}\n";
     }
 
-    return implode('', $text);
+    $this->writeOut(implode('', $text));
   }
 
-  public function renderOkayResult() {
-    return phutil_console_format(
-      "<bg:green>** %s **</bg> %s\n",
-      pht('OKAY'),
-      pht('No lint warnings.'));
+  public function renderResultCode($result_code) {
+    if ($result_code == ArcanistLintWorkflow::RESULT_OKAY) {
+      $view = new PhutilConsoleInfo(
+        pht('OKAY'),
+        pht('No lint messages.'));
+      $this->writeOut($view->drawConsoleString());
+    }
   }
 
 }
diff --git a/src/lint/renderer/__tests__/ArcanistConsoleLintRendererTestCase.php b/src/lint/renderer/__tests__/ArcanistConsoleLintRendererTestCase.php
index 9014288b..680a601e 100644
--- a/src/lint/renderer/__tests__/ArcanistConsoleLintRendererTestCase.php
+++ b/src/lint/renderer/__tests__/ArcanistConsoleLintRendererTestCase.php
@@ -1,200 +1,206 @@
 <?php
 
 final class ArcanistConsoleLintRendererTestCase
   extends PhutilTestCase {
 
   public function testRendering() {
     $midline_original = <<<EOTEXT
 import apple;
 import banana;
 import cat;
 import dog;
 EOTEXT;
 
     $midline_replacement = <<<EOTEXT
 import apple;
 import banana;
 
 import cat;
 import dog;
 EOTEXT;
 
     $remline_original = <<<EOTEXT
 import apple;
 import banana;
 
 
 import cat;
 import dog;
 EOTEXT;
 
     $remline_replacement = <<<EOTEXT
 import apple;
 import banana;
 
 import cat;
 import dog;
 EOTEXT;
 
     $map = array(
       'simple' => array(
         'line' => 1,
         'char' => 1,
         'original' => 'a',
         'replacement' => 'z',
       ),
       'inline' => array(
         'line' => 1,
         'char' => 7,
         'original' => 'cat',
         'replacement' => 'dog',
       ),
 
       // In this test, the original and replacement texts have a large
       // amount of overlap.
       'overlap' => array(
         'line' => 1,
         'char' => 1,
         'original' => 'tantawount',
         'replacement' => 'tantamount',
       ),
 
       'newline' => array(
         'line' => 6,
         'char' => 1,
         'original' => "\n",
         'replacement' => '',
       ),
 
       'addline' => array(
         'line' => 3,
         'char' => 1,
         'original' => '',
         'replacement' => "cherry\n",
       ),
 
       'addlinesuffix' => array(
         'line' => 2,
         'char' => 7,
         'original' => '',
         'replacement' => "\ncherry",
       ),
 
       'xml' => array(
         'line' => 3,
         'char' => 6,
         'original' => '',
         'replacement' => "\n",
       ),
 
       'caret' => array(
         'line' => 2,
         'char' => 13,
         'name' => 'Fruit Misinformation',
         'description' => 'Arguably untrue.',
       ),
 
       'original' => array(
         'line' => 1,
         'char' => 4,
         'original' => 'should of',
       ),
 
       'midline' => array(
         'line' => 1,
         'char' => 1,
         'original' => $midline_original,
         'replacement' => $midline_replacement,
       ),
 
       'remline' => array(
         'line' => 1,
         'char' => 1,
         'original' => $remline_original,
         'replacement' => $remline_replacement,
       ),
 
       'extrawhitespace' => array(
         'line' => 2,
         'char' => 1,
         'original' => "\n",
         'replacement' => '',
       ),
     );
 
     $defaults = array(
       'severity' => ArcanistLintSeverity::SEVERITY_WARNING,
       'name' => 'Lint Warning',
       'path' => 'path/to/example.c',
       'description' => 'Consider this.',
       'code' => 'WARN123',
     );
 
     foreach ($map as $key => $test_case) {
       $data = $this->readTestData("{$key}.txt");
       $data = preg_replace('/~+\s*$/m', '', $data);
 
       $expect = $this->readTestData("{$key}.expect");
 
       $test_case = $test_case + $defaults;
 
       $path = $test_case['path'];
       $severity = $test_case['severity'];
       $name = $test_case['name'];
       $description = $test_case['description'];
       $code = $test_case['code'];
 
       $line = $test_case['line'];
       $char = $test_case['char'];
 
       $original = idx($test_case, 'original');
       $replacement = idx($test_case, 'replacement');
 
       $message = id(new ArcanistLintMessage())
         ->setPath($path)
         ->setSeverity($severity)
         ->setName($name)
         ->setDescription($description)
         ->setCode($code)
         ->setLine($line)
         ->setChar($char)
         ->setOriginalText($original)
         ->setReplacementText($replacement);
 
       $result = id(new ArcanistLintResult())
         ->setPath($path)
         ->setData($data)
         ->addMessage($message);
 
       $renderer = id(new ArcanistConsoleLintRenderer())
         ->setTestableMode(true);
 
       try {
         PhutilConsoleFormatter::disableANSI(true);
-        $actual = $renderer->renderLintResult($result);
+
+        $tmp = new TempFile();
+        $renderer->setOutputPath($tmp);
+        $renderer->renderLintResult($result);
+        $actual = Filesystem::readFile($tmp);
+        unset($tmp);
+
         PhutilConsoleFormatter::disableANSI(false);
       } catch (Exception $ex) {
         PhutilConsoleFormatter::disableANSI(false);
         throw $ex;
       }
 
       // Trim "~" off the ends of lines. This allows the "expect" file to test
       // for trailing whitespace without actually containing trailing
       // whitespace.
       $expect = preg_replace('/~+$/m', '', $expect);
 
       $this->assertEqual(
         $expect,
         $actual,
         pht(
           'Lint rendering for "%s".',
           $key));
     }
   }
 
   private function readTestData($filename) {
     $path = dirname(__FILE__).'/data/'.$filename;
     return Filesystem::readFile($path);
   }
 
 }
diff --git a/src/workflow/ArcanistLintWorkflow.php b/src/workflow/ArcanistLintWorkflow.php
index b86cc6f7..16985bbb 100644
--- a/src/workflow/ArcanistLintWorkflow.php
+++ b/src/workflow/ArcanistLintWorkflow.php
@@ -1,449 +1,389 @@
 <?php
 
 /**
  * Runs lint rules on changes.
  */
 final class ArcanistLintWorkflow extends ArcanistWorkflow {
 
   const RESULT_OKAY       = 0;
   const RESULT_WARNINGS   = 1;
   const RESULT_ERRORS     = 2;
   const RESULT_SKIP       = 3;
 
   const DEFAULT_SEVERITY = ArcanistLintSeverity::SEVERITY_ADVICE;
 
   private $unresolvedMessages;
   private $shouldAmendChanges = false;
   private $shouldAmendWithoutPrompt = false;
   private $shouldAmendAutofixesWithoutPrompt = false;
   private $engine;
 
   public function getWorkflowName() {
     return 'lint';
   }
 
   public function setShouldAmendChanges($should_amend) {
     $this->shouldAmendChanges = $should_amend;
     return $this;
   }
 
   public function setShouldAmendWithoutPrompt($should_amend) {
     $this->shouldAmendWithoutPrompt = $should_amend;
     return $this;
   }
 
   public function setShouldAmendAutofixesWithoutPrompt($should_amend) {
     $this->shouldAmendAutofixesWithoutPrompt = $should_amend;
     return $this;
   }
 
   public function getCommandSynopses() {
     return phutil_console_format(<<<EOTEXT
       **lint** [__options__] [__paths__]
       **lint** [__options__] --rev [__rev__]
 EOTEXT
       );
   }
 
   public function getCommandHelp() {
     return phutil_console_format(<<<EOTEXT
           Supports: git, svn, hg
           Run static analysis on changes to check for mistakes. If no files
           are specified, lint will be run on all files which have been modified.
 EOTEXT
       );
   }
 
   public function getArguments() {
     return array(
       'lintall' => array(
         'help' => pht(
           'Show all lint warnings, not just those on changed lines. When '.
           'paths are specified, this is the default behavior.'),
       ),
       'rev' => array(
         'param' => 'revision',
         'help' => pht('Lint changes since a specific revision.'),
         'supports' => array(
           'git',
           'hg',
         ),
         'nosupport' => array(
           'svn' => pht('Lint does not currently support %s in SVN.', '--rev'),
         ),
       ),
       'output' => array(
         'param' => 'format',
-        'help' => pht(
-          "With 'summary', show lint warnings in a more compact format. ".
-          "With 'json', show lint warnings in machine-readable JSON format. ".
-          "With 'none', show no lint warnings. ".
-          "With 'compiler', show lint warnings in suitable for your editor. ".
-          "With 'xml', show lint warnings in the Checkstyle XML format."),
+        'help' => pht('Select an output format.'),
       ),
       'outfile' => array(
         'param' => 'path',
         'help' => pht(
           'Output the linter results to a file. Defaults to stdout.'),
       ),
       'engine' => array(
         'param' => 'classname',
         'help' => pht('Override configured lint engine for this project.'),
       ),
       'apply-patches' => array(
         'help' => pht(
           'Apply patches suggested by lint to the working copy without '.
           'prompting.'),
         'conflicts' => array(
           'never-apply-patches' => true,
         ),
       ),
       'never-apply-patches' => array(
         'help' => pht('Never apply patches suggested by lint.'),
         'conflicts' => array(
           'apply-patches' => true,
         ),
       ),
       'amend-all' => array(
         'help' => pht(
           'When linting git repositories, amend HEAD with all patches '.
           'suggested by lint without prompting.'),
       ),
       'amend-autofixes' => array(
         'help' => pht(
           'When linting git repositories, amend HEAD with autofix '.
           'patches suggested by lint without prompting.'),
       ),
       'everything' => array(
         'help' => pht('Lint all files in the project.'),
         'conflicts' => array(
           'rev' => pht('%s lints all files', '--everything'),
         ),
       ),
       'severity' => array(
         'param' => 'string',
         'help' => pht(
           "Set minimum message severity. One of: %s. Defaults to '%s'.",
           sprintf(
             "'%s'",
             implode(
               "', '",
               array_keys(ArcanistLintSeverity::getLintSeverities()))),
           self::DEFAULT_SEVERITY),
       ),
       '*' => 'paths',
     );
   }
 
   public function requiresAuthentication() {
     return false;
   }
 
   public function requiresWorkingCopy() {
     return true;
   }
 
   public function requiresRepositoryAPI() {
     return true;
   }
 
   public function run() {
     $console = PhutilConsole::getConsole();
     $working_copy = $this->getWorkingCopy();
     $configuration_manager = $this->getConfigurationManager();
 
     $engine = $this->newLintEngine($this->getArgument('engine'));
 
     $rev = $this->getArgument('rev');
     $paths = $this->getArgument('paths');
     $everything = $this->getArgument('everything');
     if ($everything && $paths) {
       throw new ArcanistUsageException(
         pht(
           'You can not specify paths with %s. The %s flag lints every file.',
           '--everything',
           '--everything'));
     }
 
     if ($rev !== null) {
       $this->parseBaseCommitArgument(array($rev));
     }
 
     // Sometimes, we hide low-severity messages which occur on lines which
     // were not changed. This is the default behavior when you run "arc lint"
     // with no arguments: if you touched a file, but there was already some
     // minor warning about whitespace or spelling elsewhere in the file, you
     // don't need to correct it.
 
     // In other modes, notably "arc lint <file>", this is not the defualt
     // behavior. If you ask us to lint a specific file, we show you all the
     // lint messages in the file.
 
     // You can change this behavior with various flags, including "--lintall",
     // "--rev", and "--everything".
     if ($this->getArgument('lintall')) {
       $lint_all = true;
     } else if ($rev !== null) {
       $lint_all = false;
     } else if ($paths || $everything) {
       $lint_all = true;
     } else {
       $lint_all = false;
     }
 
     if ($everything) {
       $paths = iterator_to_array($this->getRepositoryAPI()->getAllFiles());
     } else {
       $paths = $this->selectPathsForWorkflow($paths, $rev);
     }
 
     $this->engine = $engine;
 
     $engine->setMinimumSeverity(
       $this->getArgument('severity', self::DEFAULT_SEVERITY));
 
     // Propagate information about which lines changed to the lint engine.
     // This is used so that the lint engine can drop warning messages
     // concerning lines that weren't in the change.
     $engine->setPaths($paths);
     if ($lint_all) {
       foreach ($paths as $path) {
         // Note that getChangedLines() returns null to indicate that a file
         // is binary or a directory (i.e., changed lines are not relevant).
         $engine->setPathChangedLines(
           $path,
           $this->getChangedLines($path, 'new'));
       }
     }
 
     $failed = null;
     try {
       $engine->run();
     } catch (Exception $ex) {
       $failed = $ex;
     }
 
     $results = $engine->getResults();
 
     if ($this->getArgument('never-apply-patches')) {
       $apply_patches = false;
     } else {
       $apply_patches = true;
     }
 
     if ($this->getArgument('apply-patches')) {
       $prompt_patches = false;
     } else {
       $prompt_patches = true;
     }
 
     if ($this->getArgument('amend-all')) {
       $this->shouldAmendChanges = true;
       $this->shouldAmendWithoutPrompt = true;
     }
 
     if ($this->getArgument('amend-autofixes')) {
-      $prompt_autofix_patches = false;
       $this->shouldAmendChanges = true;
       $this->shouldAmendAutofixesWithoutPrompt = true;
-    } else {
-      $prompt_autofix_patches = true;
     }
 
     $repository_api = $this->getRepositoryAPI();
     if ($this->shouldAmendChanges) {
       $this->shouldAmendChanges = $repository_api->supportsAmend() &&
         !$this->isHistoryImmutable();
     }
 
     $wrote_to_disk = false;
 
-    switch ($this->getArgument('output')) {
-      case 'json':
-        $renderer = new ArcanistJSONLintRenderer();
-        $prompt_patches = false;
-        $apply_patches = $this->getArgument('apply-patches');
-        break;
-      case 'summary':
-        $renderer = new ArcanistSummaryLintRenderer();
-        break;
-      case 'none':
-        $prompt_patches = false;
-        $apply_patches = $this->getArgument('apply-patches');
-        $renderer = new ArcanistNoneLintRenderer();
-        break;
-      case 'compiler':
-        $renderer = new ArcanistCompilerLintRenderer();
-        $prompt_patches = false;
-        $apply_patches = $this->getArgument('apply-patches');
-        break;
-      case 'xml':
-        $renderer = new ArcanistCheckstyleXMLLintRenderer();
-        $prompt_patches = false;
-        $apply_patches = $this->getArgument('apply-patches');
-        break;
-      default:
-        $renderer = new ArcanistConsoleLintRenderer();
-        $renderer->setShowAutofixPatches($prompt_autofix_patches);
-        break;
+    $default_renderer = ArcanistConsoleLintRenderer::RENDERERKEY;
+    $renderer_key = $this->getArgument('output', $default_renderer);
+
+    $renderers = ArcanistLintRenderer::getAllRenderers();
+    if (!isset($renderers[$renderer_key])) {
+      throw new Exception(
+        pht(
+          'Lint renderer "%s" is unknown. Supported renderers are: %s.',
+          $renderer_key,
+          implode(', ', array_keys($renderers))));
     }
+    $renderer = $renderers[$renderer_key];
 
     $all_autofix = true;
-    $tmp = null;
 
-    if ($this->getArgument('outfile') !== null) {
-      $tmp = id(new TempFile())
-        ->setPreserveFile(true);
+    $out_path = $this->getArgument('outfile');
+    if ($out_path !== null) {
+      $tmp = new TempFile();
+      $renderer->setOutputPath((string)$tmp);
+    } else {
+      $tmp = null;
     }
 
-    $preamble = $renderer->renderPreamble();
-    if ($tmp) {
-      Filesystem::appendFile($tmp, $preamble);
-    } else {
-      $console->writeOut('%s', $preamble);
+    if ($failed) {
+      $renderer->handleException($failed);
     }
 
-    foreach ($results as $result) {
-      $result_all_autofix = $result->isAllAutofix();
+    $renderer->willRenderResults();
 
-      if (!$result->getMessages() && !$result_all_autofix) {
+    $should_patch = ($apply_patches && $renderer->supportsPatching());
+    foreach ($results as $result) {
+      if (!$result->getMessages()) {
         continue;
       }
 
+      $result_all_autofix = $result->isAllAutofix();
       if (!$result_all_autofix) {
         $all_autofix = false;
       }
 
-      $lint_result = $renderer->renderLintResult($result);
-      if ($lint_result) {
-        if ($tmp) {
-          Filesystem::appendFile($tmp, $lint_result);
-        } else {
-          $console->writeOut('%s', $lint_result);
-        }
-      }
+      $renderer->renderLintResult($result);
 
-      if ($apply_patches && $result->isPatchable()) {
+      if ($should_patch && $result->isPatchable()) {
         $patcher = ArcanistLintPatcher::newFromArcanistLintResult($result);
-        $old_file = $result->getFilePathOnDisk();
 
-        if ($prompt_patches &&
-            !($result_all_autofix && !$prompt_autofix_patches)) {
+        $apply = true;
+        if ($prompt_patches && !$result_all_autofix) {
+          $old_file = $result->getFilePathOnDisk();
           if (!Filesystem::pathExists($old_file)) {
-            $old_file = '/dev/null';
+            $old_file = null;
           }
+
           $new_file = new TempFile();
           $new = $patcher->getModifiedFileContent();
           Filesystem::writeFile($new_file, $new);
 
-          // TODO: Improve the behavior here, make it more like
-          // difference_render().
-          list(, $stdout, $stderr) =
-            exec_manual('diff -u %s %s', $old_file, $new_file);
-          $console->writeOut('%s', $stdout);
-          $console->writeErr('%s', $stderr);
-
-          $prompt = pht(
-            'Apply this patch to %s?',
-            phutil_console_format('__%s__', $result->getPath()));
-          if (!phutil_console_confirm($prompt, $default_no = false)) {
-            continue;
-          }
+          $apply = $renderer->promptForPatch($result, $old_file, $new_file);
         }
 
-        $patcher->writePatchToDisk();
-        $wrote_to_disk = true;
+        if ($apply) {
+          $patcher->writePatchToDisk();
+          $wrote_to_disk = true;
+        }
       }
     }
 
-    $postamble = $renderer->renderPostamble();
+    $renderer->didRenderResults();
+
     if ($tmp) {
-      Filesystem::appendFile($tmp, $postamble);
-      Filesystem::rename($tmp, $this->getArgument('outfile'));
-    } else {
-      $console->writeOut('%s', $postamble);
+      Filesystem::rename($tmp, $out_path);
     }
 
     if ($wrote_to_disk && $this->shouldAmendChanges) {
       if ($this->shouldAmendWithoutPrompt ||
           ($this->shouldAmendAutofixesWithoutPrompt && $all_autofix)) {
         $console->writeOut(
           "<bg:yellow>** %s **</bg> %s\n",
           pht('LINT NOTICE'),
           pht('Automatically amending HEAD with lint patches.'));
         $amend = true;
       } else {
         $amend = phutil_console_confirm(pht('Amend HEAD with lint patches?'));
       }
 
       if ($amend) {
         if ($repository_api instanceof ArcanistGitAPI) {
           // Add the changes to the index before amending
           $repository_api->execxLocal('add -u');
         }
 
         $repository_api->amendCommit();
       } else {
         throw new ArcanistUsageException(
           pht(
             'Sort out the lint changes that were applied to the working '.
             'copy and relint.'));
       }
     }
 
-    if ($this->getArgument('output') == 'json') {
-      // NOTE: Required by save_lint.php in Phabricator.
-      return 0;
-    }
-
-    if ($failed) {
-      if ($failed instanceof ArcanistNoEffectException) {
-        if ($renderer instanceof ArcanistNoneLintRenderer) {
-          return 0;
-        }
-      }
-      throw $failed;
-    }
-
     $unresolved = array();
     $has_warnings = false;
     $has_errors = false;
 
     foreach ($results as $result) {
       foreach ($result->getMessages() as $message) {
         if (!$message->isPatchApplied()) {
           if ($message->isError()) {
             $has_errors = true;
           } else if ($message->isWarning()) {
             $has_warnings = true;
           }
           $unresolved[] = $message;
         }
       }
     }
     $this->unresolvedMessages = $unresolved;
 
     // Take the most severe lint message severity and use that
     // as the result code.
     if ($has_errors) {
       $result_code = self::RESULT_ERRORS;
     } else if ($has_warnings) {
       $result_code = self::RESULT_WARNINGS;
     } else {
       $result_code = self::RESULT_OKAY;
     }
 
-    if (!$this->getParentWorkflow()) {
-      if ($result_code == self::RESULT_OKAY) {
-        $console->writeOut('%s', $renderer->renderOkayResult());
-      }
-    }
+    $renderer->renderResultCode($result_code);
 
     return $result_code;
   }
 
   public function getUnresolvedMessages() {
     return $this->unresolvedMessages;
   }
 
 }