Port flake8 to ArcanistExternalLinter

Summary:
Ref T3186. Brings another linter onboard. This one uses the stdin stuff.

The unit test was ostensibly broken so I fixed it, but that might just be some kind of version issue.

Test Plan: Unit tests.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T3186

Differential Revision: https://secure.phabricator.com/D6802

src/__phutil_library_map__.php

@@ -221,7 +221,7 @@ phutil_register_library_map(array(
     'ArcanistFeatureWorkflow' => 'ArcanistBaseWorkflow',
     'ArcanistFilenameLinter' => 'ArcanistLinter',
     'ArcanistFlagWorkflow' => 'ArcanistBaseWorkflow',
-    'ArcanistFlake8Linter' => 'ArcanistLinter',
+    'ArcanistFlake8Linter' => 'ArcanistExternalLinter',
     'ArcanistFlake8LinterTestCase' => 'ArcanistArcanistLinterTestCase',
     'ArcanistFutureLinter' => 'ArcanistLinter',
     'ArcanistGeneratedLinter' => 'ArcanistLinter',

src/lint/linter/ArcanistExternalLinter.php

@@ -371,7 +371,7 @@ abstract class ArcanistExternalLinter extends ArcanistFutureLinter {
           '%C %C',
           $bin,
           $this->getReadDataFromStdinFilename());
-        $future->write($this->getFileData($path));
+        $future->write($this->getEngine()->loadData($path));
       } else {
         // TODO: In commit hook mode, we need to do more handling here.
         $disk_path = $this->getEngine()->getFilePathOnDisk($path);

src/lint/linter/ArcanistFlake8Linter.php

@@ -6,17 +6,15 @@
  *
  * @group linter
  */
-final class ArcanistFlake8Linter extends ArcanistLinter {
-
-  public function willLintPaths(array $paths) {
-    return;
-  }
+final class ArcanistFlake8Linter extends ArcanistExternalLinter {
 
   public function getLinterName() {
     return 'flake8';
   }
 
-  public function getFlake8Options() {
+  public function getDefaultFlags() {
+    // TODO: Deprecated.
+
     $working_copy = $this->getEngine()->getWorkingCopy();
 
     $options = $working_copy->getConfig('lint.flake8.options', '');
@@ -24,59 +22,44 @@ final class ArcanistFlake8Linter extends ArcanistLinter {
     return $options;
   }
 
-  public function getFlake8Path() {
+  public function getDefaultBinary() {
     $working_copy = $this->getEngine()->getWorkingCopy();
     $prefix = $working_copy->getConfig('lint.flake8.prefix');
     $bin = $working_copy->getConfig('lint.flake8.bin', 'flake8');
 
-    if ($prefix !== null) {
-      if (!Filesystem::pathExists($prefix.'/'.$bin)) {
-        throw new ArcanistUsageException(
-          "Unable to find flake8 binary in a specified directory. Make sure ".
-          "that 'lint.flake8.prefix' and 'lint.flake8.bin' keys are set ".
-          "correctly. If you'd rather use a copy of flake8 installed ".
-          "globally, you can just remove these keys from your .arcconfig.");
+    if ($prefix || ($bin != 'flake8')) {
+      return $prefix.'/'.$bin;
     }
 
-      $bin = csprintf("%s/%s", $prefix, $bin);
-
-      return $bin;
+    return 'flake8';
   }
 
-    // Look for globally installed flake8
-    list($err) = exec_manual('which %s', $bin);
-    if ($err) {
-      throw new ArcanistUsageException(
-        "flake8 does not appear to be installed on this system. Install it ".
-        "(e.g., with 'easy_install flake8') or configure ".
-        "'lint.flake8.prefix' in your .arcconfig to point to the directory ".
-        "where it resides.");
+  public function getInstallInstructions() {
+    return pht('Install flake8 using `easy_install flake8`.');
   }
 
-    return $bin;
+  public function supportsReadDataFromStdin() {
+    return true;
   }
 
-  public function lintPath($path) {
-    $flake8_bin = $this->getFlake8Path();
-    $options = $this->getFlake8Options();
-
-    $f = new ExecFuture("%C %C -", $flake8_bin, $options);
-    $f->write($this->getData($path));
-
-    list($err, $stdout, $stderr) = $f->resolve();
-
-    if ($err === 2) {
-      throw new Exception("flake8 failed to run correctly:\n".$stderr);
+  public function getReadDataFromStdinFilename() {
+    return '-';
   }
 
-    $lines = explode("\n", $stdout);
+  public function shouldExpectCommandErrors() {
+    return true;
+  }
+
+  protected function parseLinterOutput($path, $err, $stdout, $stderr) {
+    $lines = phutil_split_lines($stdout, $retain_endings = false);
+
     $messages = array();
     foreach ($lines as $line) {
       $matches = null;
       // stdin:2: W802 undefined name 'foo'  # pyflakes
       // stdin:3:1: E302 expected 2 blank lines, found 1  # pep8
-      if (!preg_match('/^(.*?):(\d+):(?:(\d+):)? (\S+) (.*)$/',
-                      $line, $matches)) {
+      $regexp = '/^(.*?):(\d+):(?:(\d+):)? (\S+) (.*)$/';
+      if (!preg_match($regexp, $line, $matches)) {
         continue;
       }
       foreach ($matches as $key => $match) {
@@ -92,14 +75,22 @@ final class ArcanistFlake8Linter extends ArcanistLinter {
       $message = new ArcanistLintMessage();
       $message->setPath($path);
       $message->setLine($matches[2]);
-      if (!empty($matches[3]))
+      if (!empty($matches[3])) {
         $message->setChar($matches[3]);
+      }
       $message->setCode($matches[4]);
       $message->setName($this->getLinterName().' '.$matches[3]);
       $message->setDescription($matches[5]);
       $message->setSeverity($severity);
-      $this->addLintMessage($message);
+
+      $messages[] = $message;
     }
+
+    if ($err && !$messages) {
+      return false;
+    }
+
+    return $messages;
   }
 
 }

src/lint/linter/__tests__/ArcanistFlake8LinterTestCase.php

@@ -9,7 +9,7 @@ final class ArcanistFlake8LinterTestCase
 
   public function testFlake8Lint() {
     return $this->executeTestsInDirectory(
-      dirname(__FILE__).'/python/',
+      dirname(__FILE__).'/flake8/',
       new ArcanistFlake8Linter());
   }
 

src/lint/linter/__tests__/flake8/undefined.lint-test

@@ -3,5 +3,5 @@ x = 'y'
 def hello():
     return foo
 ~~~~~~~~~~
-warning:1:8
-warning:4:
+error:3:1
+warning:4:1