Modularize "arc lint" renderers

Summary:
Ref T12996. `arc lint` can render in different formats with `--output <format>`.

Previously, these were a big `switch()` statement and a bunch of hard-coded stuff.

Modularize them so that that third parties could add new renderers, and this code can be refactored toward parallelizing the `lint` step.

This has a small behavioral change: we no longer hide "autofix" messages. I'd like to generally simplify the number of amend/autofix flags here, so this edges us toward that slightly.

Test Plan: Ran `arc lint` with all the `--output` flags in states with warnings and no warnings, saw sensible-seeming behavior.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T12996

Differential Revision: https://secure.phabricator.com/D18645

src/lint/renderer/ArcanistCheckstyleXMLLintRenderer.php

@@ -1,10 +1,9 @@
 <?php
 
-/**
- * Shows lint messages to the user.
- */
 final class ArcanistCheckstyleXMLLintRenderer extends ArcanistLintRenderer {
 
+  const RENDERERKEY = 'xml';
+
   private $writer;
 
   public function __construct() {
@@ -14,11 +13,11 @@ final class ArcanistCheckstyleXMLLintRenderer extends ArcanistLintRenderer {
     $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) {
@@ -39,17 +38,13 @@ final class ArcanistCheckstyleXMLLintRenderer extends ArcanistLintRenderer {
     }
 
     $this->writer->endElement();
-    return $this->writer->flush();
+    $this->writeOut($this->writer->flush());
   }
 
-  public function renderOkayResult() {
-    return '';
-  }
-
-  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) {

src/lint/renderer/ArcanistCompilerLintRenderer.php

@@ -1,10 +1,9 @@
 <?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();
@@ -25,11 +24,7 @@ final class ArcanistCompilerLintRenderer extends ArcanistLintRenderer {
         $description);
     }
 
-    return implode('', $lines);
-  }
-
-  public function renderOkayResult() {
-    return '';
+    $this->writeOut(implode('', $lines));
   }
 
 }

src/lint/renderer/ArcanistConsoleLintRenderer.php

@@ -1,17 +1,10 @@
 <?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;
@@ -22,6 +15,38 @@ final class ArcanistConsoleLintRenderer extends ArcanistLintRenderer {
     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();
@@ -31,10 +56,6 @@ final class ArcanistConsoleLintRenderer extends ArcanistLintRenderer {
 
     $text = array();
     foreach ($messages as $message) {
-      if (!$this->showAutofixPatches && $message->isAutofix()) {
-        continue;
-      }
-
       if ($message->isError()) {
         $color = 'red';
       } else {
@@ -77,9 +98,7 @@ final class ArcanistConsoleLintRenderer extends ArcanistLintRenderer {
         pht(
           'Lint for %s:',
           phutil_console_format('__%s__', $path)));
-      return $prefix.implode("\n", $text);
-    } else {
-      return null;
+      $this->writeOut($prefix.implode("\n", $text));
     }
   }
 
@@ -278,13 +297,6 @@ final class ArcanistConsoleLintRenderer extends ArcanistLintRenderer {
       $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);
 

src/lint/renderer/ArcanistJSONLintRenderer.php

@@ -1,10 +1,9 @@
 <?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) {
@@ -25,11 +24,7 @@ final class ArcanistJSONLintRenderer extends ArcanistLintRenderer {
       $output[$path][] = $dictionary;
     }
 
-    return json_encode($output)."\n";
-  }
-
-  public function renderOkayResult() {
-    return '';
+    $this->writeOut(json_encode($output)."\n");
   }
 
 }

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;
   }
 
 }

src/lint/renderer/ArcanistNoneLintRenderer.php

@@ -2,12 +2,10 @@
 
 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;
   }
 
 }

src/lint/renderer/ArcanistSummaryLintRenderer.php

@@ -1,10 +1,9 @@
 <?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();
@@ -19,14 +18,16 @@ final class ArcanistSummaryLintRenderer extends ArcanistLintRenderer {
       $text[] = "{$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());
+    }
   }
 
 }

src/lint/renderer/__tests__/ArcanistConsoleLintRendererTestCase.php

@@ -171,7 +171,13 @@ EOTEXT;
 
       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);

src/workflow/ArcanistLintWorkflow.php

@@ -74,12 +74,7 @@ EOTEXT
       ),
       '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',
@@ -243,11 +238,8 @@ EOTEXT
     }
 
     if ($this->getArgument('amend-autofixes')) {
-      $prompt_autofix_patches = false;
       $this->shouldAmendChanges = true;
       $this->shouldAmendAutofixesWithoutPrompt = true;
-    } else {
-      $prompt_autofix_patches = true;
     }
 
     $repository_api = $this->getRepositoryAPI();
@@ -258,110 +250,76 @@ EOTEXT
 
     $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);
-    }
-
-    $preamble = $renderer->renderPreamble();
-    if ($tmp) {
-      Filesystem::appendFile($tmp, $preamble);
+    $out_path = $this->getArgument('outfile');
+    if ($out_path !== null) {
+      $tmp = new TempFile();
+      $renderer->setOutputPath((string)$tmp);
     } else {
-      $console->writeOut('%s', $preamble);
+      $tmp = null;
     }
 
-    foreach ($results as $result) {
-      $result_all_autofix = $result->isAllAutofix();
+    if ($failed) {
+      $renderer->handleException($failed);
+    }
 
-      if (!$result->getMessages() && !$result_all_autofix) {
+    $renderer->willRenderResults();
+
+    $should_patch = ($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) {
@@ -391,20 +349,6 @@ EOTEXT
       }
     }
 
-    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;
@@ -433,11 +377,7 @@ EOTEXT
       $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;
   }