Bug 1229859 - Introduce new import-globals-from eslint rule to import globals from other modules; r=Mossop

devtools/.eslintrc

@@ -25,6 +25,7 @@
     // Rules from the mozilla plugin
     "mozilla/balanced-listeners": 2,
     "mozilla/components-imports": 1,
+    "mozilla/import-globals-from": 1,
     "mozilla/import-headjs-globals": 1,
     "mozilla/mark-test-function-used": 1,
     "mozilla/no-aArgs": 1,

devtools/client/animationinspector/animation-panel.js

@@ -3,7 +3,8 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-/* globals AnimationsController, document, promise, gToolbox, gInspector */
+/* import-globals-from animation-controller.js */
+/* globals document */
 
 "use strict";
 

testing/eslint-plugin-mozilla/docs/import-globals-from.rst

@@ -0,0 +1,18 @@
+.. _import-globals-from:
+
+===================
+import-globals-from
+===================
+
+Rule Details
+------------
+
+When the "import-globals-from <path>" comment is found in a file, then all
+globals from the file at <path> will be imported in the current scope.
+
+This is useful for tests that rely on globals defined in head.js files, or for
+scripts that are loaded as <script> tag in a window in rely on eachother's
+globals.
+
+If <path> is a relative path, then it must be relative to the file being
+checked by the rule.

testing/eslint-plugin-mozilla/docs/index.rst

@@ -10,6 +10,10 @@ removeEventListener (and does the same for on/off).
 ``components-imports`` adds the filename of imported files e.g.
 ``Cu.import("some/path/Blah.jsm")`` adds Blah to the global scope.
 
+``import-globals-from`` When the "import-globals-from <path>" comment is found
+in a file, then all globals from the file at <path> will be imported in the
+current scope.
+
 ``import-headjs-globals`` imports globals from head.js and from any files that
 should be imported by head.js (as far as we can correctly resolve the path).
 
@@ -47,6 +51,7 @@ Example configuration::
    "rules": {
      "mozilla/balanced-listeners": 2,
      "mozilla/components-imports": 1,
+     "mozilla/import-globals-from": 1,
      "mozilla/import-headjs-globals": 1,
      "mozilla/mark-test-function-used": 1,
      "mozilla/var-only-at-top-level": 1,
@@ -58,6 +63,7 @@ Example configuration::
 
    balanced-listeners
    components-imports
+   import-globals-from
    import-headjs-globals
    mark-test-function-used
    no-aArgs

testing/eslint-plugin-mozilla/lib/helpers.js

@@ -8,6 +8,7 @@
 
 var escope = require("escope");
 var espree = require("espree");
+var path = require("path");
 
 var regexes = [
   /^(?:Cu|Components\.utils)\.import\(".*\/(.*?)\.jsm?"\);?$/,
@@ -232,5 +233,33 @@ module.exports = {
     var pathAndFilename = scope.getFilename();
 
     return /.*[\\/]browser_.+\.js$/.test(pathAndFilename);
+  },
+
+  /**
+   * ESLint may be executed from various places: from mach, at the root of the
+   * repository, or from a directory in the repository when, for instance,
+   * executed by a text editor's plugin.
+   * The value returned by context.getFileName() varies because of this.
+   * This helper function makes sure to return an absolute file path for the
+   * current context, by looking at process.cwd().
+   * @param {Context} context
+   * @return {String} The absolute path
+   */
+  getAbsoluteFilePath: function(context) {
+    var fileName = context.getFilename();
+    var cwd = process.cwd();
+
+    if (path.isAbsolute(fileName)) {
+      // Case 2: executed from the repo's root with mach:
+      //   fileName: /path/to/mozilla/repo/a/b/c/d.js
+      //   cwd: /path/to/mozilla/repo
+      return fileName;
+    } else {
+      // Case 1: executed form in a nested directory, e.g. from a text editor:
+      //   fileName: a/b/c/d.js
+      //   cwd: /path/to/mozilla/repo/a/b/c
+      var dirName = path.dirname(fileName);
+      return cwd.slice(0, cwd.length - dirName.length) + fileName;
+    }
   }
 };

testing/eslint-plugin-mozilla/lib/index.js

@@ -19,6 +19,7 @@ module.exports = {
   rules: {
     "balanced-listeners": require("../lib/rules/balanced-listeners"),
     "components-imports": require("../lib/rules/components-imports"),
+    "import-globals-from": require("../lib/rules/import-globals-from"),
     "import-headjs-globals": require("../lib/rules/import-headjs-globals"),
     "mark-test-function-used": require("../lib/rules/mark-test-function-used"),
     "no-aArgs": require("../lib/rules/no-aArgs"),
@@ -28,6 +29,7 @@ module.exports = {
   rulesConfig: {
     "balanced-listeners": 0,
     "components-imports": 0,
+    "import-globals-from": 0,
     "import-headjs-globals": 0,
     "mark-test-function-used": 0,
     "no-aArgs": 0,

testing/eslint-plugin-mozilla/lib/rules/import-globals-from.js

@@ -0,0 +1,78 @@
+/**
+ * @fileoverview When the "import-globals-from: <path>" comment is found in a
+ * file, then all globals from the file at <path> will be imported in the
+ * current scope.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+// -----------------------------------------------------------------------------
+// Rule Definition
+// -----------------------------------------------------------------------------
+
+var fs = require("fs");
+var helpers = require("../helpers");
+var path = require("path");
+
+module.exports = function(context) {
+  // ---------------------------------------------------------------------------
+  // Helpers
+  // ---------------------------------------------------------------------------
+
+  function importGlobalsFrom(filePath) {
+    // If the file can't be found, let the error go up to the caller so it can
+    // be logged as an error in the current file.
+    var content = fs.readFileSync(filePath, "utf8");
+
+    // Parse the content and get the globals from the ast.
+    var ast = helpers.getAST(content);
+    var globalVars = helpers.getGlobals(ast);
+
+    for (var i = 0; i < globalVars.length; i++) {
+      var varName = globalVars[i];
+      helpers.addVarToScope(varName, context);
+    }
+  }
+
+  // ---------------------------------------------------------------------------
+  // Public
+  // ---------------------------------------------------------------------------
+
+  return {
+    Program: function(node) {
+      var comments = context.getSourceCode().getAllComments();
+
+      comments.forEach(function(comment) {
+        var value = comment.value.trim();
+        var match = /^import-globals-from\s+(.*)$/.exec(value);
+
+        if (match) {
+          var currentFilePath = helpers.getAbsoluteFilePath(context);
+          var filePath = match[1];
+
+          if (!path.isAbsolute(filePath)) {
+            var dirName = path.dirname(currentFilePath);
+            filePath = path.resolve(dirName, filePath);
+          }
+
+          try {
+            importGlobalsFrom(filePath);
+          } catch (e) {
+            context.report(
+              node,
+              "Could not load globals from file {{filePath}}: {{error}}",
+              {
+                filePath: filePath,
+                error: e
+              }
+            );
+          }
+        }
+      });
+    }
+  };
+};

testing/eslint-plugin-mozilla/lib/rules/import-headjs-globals.js

@@ -91,12 +91,11 @@ module.exports = function(context) {
         return;
       }
 
-      var testPath = this.getFilename();
-      var testFilename = path.basename(testPath);
-      var fullTestPath = path.resolve(testFilename);
-      var fullHeadjsPath = path.resolve("head.js");
+      var currentFilePath = helpers.getAbsoluteFilePath(context);
+      var dirName = path.dirname(currentFilePath);
+      var fullHeadjsPath = path.resolve(dirName, "head.js");
 
-      checkFile([fullTestPath, fullHeadjsPath]);
+      checkFile([currentFilePath, fullHeadjsPath]);
     }
   };
 };