Support auto-fixing AST-based linters

fixes hhvm#79

src/Linters/ASTLintError.php

@@ -50,7 +50,6 @@ final public function getRange(): ((int, int), (int, int)) {
     );
   }
 
-  <<__Override>>
   final public function getBlameCode(): string {
     return $this->node->getCode();
   }

src/Linters/AutoFixingASTLinter.php

@@ -11,14 +11,60 @@
 namespace Facebook\HHAST\Linters;
 
 use type Facebook\HHAST\EditableNode;
+use namespace Facebook\HHAST\__Private\LSP;
 use namespace Facebook\HHAST;
+use namespace HH\Lib\{C, Str};
 
 abstract class AutoFixingASTLinter<Tnode as EditableNode>
 extends BaseASTLinter<Tnode, FixableASTLintError<Tnode>>
-implements AutoFixingLinter<FixableASTLintError<Tnode>> {
+implements LSPAutoFixingLinter<FixableASTLintError<Tnode>> {
 
   abstract public function getFixedNode(Tnode $node): ?EditableNode;
 
+  final public function getCodeActionForError(
+    FixableASTLintError<Tnode> $error,
+  ): ?LSP\CodeAction {
+    $node = $error->getBlameNode();
+    $fixed = $this->getFixedNode($node);
+    if ($fixed === null) {
+      return null;
+    }
+
+    $offset = HHAST\find_offset_of_leading($this->getAST(), $node);
+    $start = $this->getAST()->getCode()
+      |> Str\slice($$, 0, $offset)
+      |> Str\split($$, "\n")
+      |> tuple(C\count($$), Str\length(C\lastx($$)));
+
+    $code = $node->getCode();
+    $lines = Str\split($code, "\n");
+    $count = C\count($lines);
+    if ($count === 1) {
+      $end = tuple($start[0], $start[1] + Str\length($code));
+    } else {
+      $end = tuple($start[0] + $count - 1, Str\length(C\lastx($lines)));
+    }
+    return shape(
+      'title' => \get_class($this)
+        |> Str\split($$, "\\")
+        |> C\lastx($$)
+        |> Str\strip_suffix($$, "Linter")
+        |> 'Fix '.$$,
+      'edit' => shape(
+        'changes' => dict[
+          'file://'.\realpath($this->getFile()) => vec[shape(
+            'range' => shape(
+              'start' =>
+                shape('line' => $start[0] - 1, 'character' => $start[1]),
+              'end' => shape('line' => $end[0] - 1, 'character' => $end[1]),
+            ),
+            'newText' => $fixed->getCode(),
+          )],
+        ],
+      ),
+    );
+  }
+
   final public function fixLintErrors(
     Traversable<FixableASTLintError<Tnode>> $errors,
   ): void {

src/Linters/LSPAutoFixingLinter.php

@@ -0,0 +1,20 @@
+<?hh // strict
+/*
+ *  Copyright (c) 2017-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the MIT license found in the
+ *  LICENSE file in the root directory of this source tree.
+ *
+ */
+
+namespace Facebook\HHAST\Linters;
+
+use type Facebook\HHAST\EditableNode;
+use namespace Facebook\HHAST;
+
+interface LSPAutoFixingLinter<Terror as FixableLintError> extends AutoFixingLinter<Terror> {
+  public function getCodeActionForError(
+    Terror $err,
+  ): ?\Facebook\HHAST\__Private\LSP\CodeAction;
+}

src/__Private/LSPImpl/CodeActionCommand.php

@@ -0,0 +1,44 @@
+<?hh // strict
+/*
+ *  Copyright (c) 2017-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the MIT license found in the
+ *  LICENSE file in the root directory of this source tree.
+ *
+ */
+
+namespace Facebook\HHAST\__Private\LSPImpl;
+
+use type Facebook\HHAST\__Private\{
+  LintRunConfig,
+  LintRunLSPCodeActionEventHandler,
+};
+use namespace Facebook\HHAST\__Private\{LSP, LSPLib};
+use namespace HH\Lib\Str;
+
+final class CodeActionCommand extends LSPLib\CodeActionCommand {
+  const type TResponse = vec<LSP\CodeAction>;
+
+  public function __construct(
+    private LSPLib\Client $client,
+    private ?LintRunConfig $config,
+  ) {
+  }
+
+  <<__Override>>
+  public async function executeAsync(
+    self::TParams $p,
+  ): Awaitable<this::TExecuteResult> {
+    $uri = $p['textDocument']['uri'];
+
+    $handler = new LintRunLSPCodeActionEventHandler(
+      $this->client,
+      $p['context']['diagnostics'],
+    );
+
+    await relint_uri_async($handler, $this->config, $uri);
+
+    return self::success($handler->getCodeActions());
+  }
+}

src/__Private/LSPImpl/DidChangeWatchedFilesNotification.php

@@ -13,7 +13,7 @@
 use type Facebook\HHAST\__Private\{
   LintRun,
   LintRunConfig,
-  LintRunLSPErrorHandler,
+  LintRunLSPPublishDiagnosticsEventHandler,
 };
 use type Facebook\CLILib\ITerminal;
 use namespace Facebook\HHAST\__Private\{LSP, LSPLib};
@@ -63,6 +63,10 @@ public function __construct(
       );
     }
 
-    await relint_uris_async($this->client, $this->config, $to_relint);
+    await relint_uris_async(
+      new LintRunLSPPublishDiagnosticsEventHandler($this->client),
+      $this->config,
+      $to_relint,
+    );
   }
 }

src/__Private/LSPImpl/DidOpenTextDocumentNotification.php

@@ -13,7 +13,7 @@
 use type Facebook\HHAST\__Private\{
   LintRun,
   LintRunConfig,
-  LintRunLSPErrorHandler,
+  LintRunLSPPublishDiagnosticsEventHandler,
 };
 use type Facebook\CLILib\ITerminal;
 use namespace Facebook\HHAST\__Private\{LSP, LSPLib};
@@ -38,6 +38,10 @@ public function __construct(
 
     $this->state->openFiles[] = $uri;
 
-    await relint_uri_async($this->client, $this->config, $uri);
+    await relint_uri_async(
+      new LintRunLSPPublishDiagnosticsEventHandler($this->client),
+      $this->config,
+      $uri,
+    );
   }
 }

src/__Private/LSPImpl/DidSaveTextDocumentNotification.php

@@ -13,7 +13,7 @@
 use type Facebook\HHAST\__Private\{
   LintRun,
   LintRunConfig,
-  LintRunLSPErrorHandler,
+  LintRunLSPPublishDiagnosticsEventHandler,
 };
 use type Facebook\CLILib\ITerminal;
 use namespace Facebook\HHAST\__Private\{LSP, LSPLib};
@@ -35,6 +35,10 @@ public function __construct(
       return;
     }
 
-    await relint_uri_async($this->client, $this->config, $uri);
+    await relint_uri_async(
+      new LintRunLSPPublishDiagnosticsEventHandler($this->client),
+      $this->config,
+      $uri,
+    );
   }
 }

src/__Private/LSPImpl/InitializeCommand.php

@@ -26,8 +26,9 @@ final class InitializeCommand
         'includeText' => false,
       ),
       'openClose' => true,
-    )
-  );
+      ),
+      'codeActionProvider' => true,
+    );
 
   <<__Override>>
   public async function executeAsync(

src/__Private/LSPImpl/Server.php

@@ -34,6 +34,7 @@ protected function getSupportedServerCommands(): vec<LSPLib\ServerCommand> {
     return vec[
       new LSPImpl\InitializeCommand($this->state),
       new LSPLib\ShutdownCommand($this->state),
+      new LSPImpl\CodeActionCommand($this->client, $this->config),
     ];
   }
 

src/__Private/LSPImpl/relint_uri_async.php

@@ -13,19 +13,18 @@
 use type Facebook\HHAST\__Private\{
   LintRun,
   LintRunConfig,
+  LintRunEventHandler,
   LintRunLSPEventHandler,
 };
-use namespace Facebook\HHAST\__Private\{LSP, LSPLib};
 use namespace HH\Lib\Str;
 
 async function relint_uri_async(
-  LSPLib\Client $client,
+  LintRunEventHandler $handler,
   ?LintRunConfig $config,
   string $uri,
 ): Awaitable<void> {
   $path = Str\strip_prefix($uri, 'file://');
   $config = $config ?? LintRunConfig::getForPath($path);
 
-  $handler = (new LintRunLSPEventHandler($client));
   await (new LintRun($config, $handler, vec[$path]))->runAsync();
 }

src/__Private/LSPImpl/relint_uris_async.php

@@ -12,19 +12,16 @@
 
 use type Facebook\HHAST\__Private\{
   LintRun,
-  LintRunConfig,
-  LintRunLSPErrorHandler,
-};
-use namespace Facebook\HHAST\__Private\{LSP, LSPLib};
+  LintRunConfig, LintRunEventHandler};
 use namespace HH\Lib\{Str, Vec};
 
 async function relint_uris_async(
-  LSPLib\Client $client,
+  LintRunEventHandler $handler,
   ?LintRunConfig $config,
   vec<string> $uris,
 ): Awaitable<void> {
   await Vec\map_async(
     $uris,
-    async $uri ==> await relint_uri_async($client, $config, $uri),
+    async $uri ==> await relint_uri_async($handler, $config, $uri),
   );
 }

src/__Private/LSPLib/CodeActionCommand.php

@@ -0,0 +1,20 @@
+<?hh // strict
+/*
+ *  Copyright (c) 2017-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the MIT license found in the
+ *  LICENSE file in the root directory of this source tree.
+ *
+ */
+
+namespace Facebook\HHAST\__Private\LSPLib;
+
+use namespace Facebook\HHAST\__Private\LSP;
+
+abstract class CodeActionCommand extends ServerCommand {
+  const string METHOD = 'textDocument/codeAction';
+  const type TParams = LSP\CodeActionParams;
+  const type TErrorCode = int;
+  const type TErrorData = mixed;
+}

src/__Private/LintRunLSPCodeActionEventHandler.php

@@ -0,0 +1,87 @@
+<?hh // strict
+/*
+ *  Copyright (c) 2017-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the MIT license found in the
+ *  LICENSE file in the root directory of this source tree.
+ *
+ */
+
+namespace Facebook\HHAST\__Private;
+
+use namespace Facebook\HHAST\Linters;
+use namespace Facebook\HHAST\__Private\{LSP, LSPLib};
+use namespace HH\Lib\{C, Dict, Str, Vec};
+
+final class LintRunLSPCodeActionEventHandler implements LintRunEventHandler {
+  private vec<LSP\CodeAction> $codeActions = vec[];
+
+  public function __construct(
+    private LSPLib\Client $client,
+    private vec<LSP\Diagnostic> $diagnostics,
+  ) {
+  }
+
+  public function linterRaisedErrors(
+    Linters\BaseLinter $linter,
+    LintRunConfig::TFileConfig $_config,
+    Traversable<Linters\LintError> $errors,
+  ): LintAutoFixResult {
+    if (!$linter instanceof Linters\LSPAutoFixingLinter) {
+      return LintAutoFixResult::SOME_UNFIXED;
+    }
+
+    $linter_class = \get_class($linter);
+    foreach ($errors as $error) {
+      $d = $this->findDiagnostic($linter, $error);
+      if ($d === null) {
+        continue;
+      }
+
+      $action = $linter->getCodeActionForError($error);
+      if ($action === null) {
+        continue;
+      }
+      $action['diagnostics'] = vec[$d];
+      $this->codeActions[] = $action;
+    }
+
+    return LintAutoFixResult::SOME_UNFIXED;
+  }
+
+  private function findDiagnostic(
+    Linters\BaseLinter $linter,
+    Linters\LintError $error,
+  ): ?LSP\Diagnostic {
+    $linter = \get_class($linter)
+      |> Str\split($$, "\\")
+      |> C\lastx($$)
+      |> Str\strip_suffix($$, "Linter");
+    $pos = $error->getPosition() ?? tuple(0, 0);
+    $start = shape(
+      'line' => $pos[0] - 1,
+      'character' => $pos[1],
+    );
+    foreach ($this->diagnostics as $d) {
+      if (($d['code'] ?? '') !== $linter) {
+        continue;
+      }
+      if ($d['range']['start'] !== $start) {
+        continue;
+      }
+      return $d;
+    }
+    return null;
+  }
+
+  public function finishedFile(string $_path, LintRunResult $_result): void {
+  }
+
+  public function finishedRun(LintRunResult $_): void {
+  }
+
+  public function getCodeActions(): vec<LSP\CodeAction> {
+    return $this->codeActions;
+  }
+}