support the externs tag (Closure Compiler only) (jsdoc#605)

Author: hegemonic

lib/jsdoc/tag/dictionary/definitions.js

@@ -866,6 +866,10 @@ exports.closureTags = {
     export: {
         onTagged: ignore
     },
+    // Closure Compiler only
+    externs: {
+        onTagged: ignore
+    },
     extends: cloneTagDef(baseTags.augments),
     final: cloneTagDef(baseTags.readonly),
     implements: cloneTagDef(baseTags.implements),

test/fixtures/externstag.js

@@ -0,0 +1,5 @@
+/**
+ * This is an externs file.
+ *
+ * @externs
+ */

test/specs/externstag.js

@@ -0,0 +1,42 @@
+'use strict';
+
+describe('@externs tag', function() {
+    var env = require('jsdoc/env');
+    var logger = require('jsdoc/util/logger');
+
+    var allowUnknownTags = Boolean(env.conf.tags.allowUnknownTags);
+
+    beforeEach(function() {
+        env.conf.tags.allowUnknownTags = false;
+        spyOn(logger, 'error');
+    });
+
+    afterEach(function() {
+        jasmine.restoreTagDictionary();
+        env.conf.tags.allowUnknownTags = allowUnknownTags;
+    });
+
+    describe('JSDoc tags', function() {
+        beforeEach(function() {
+            jasmine.replaceTagDictionary('jsdoc');
+        });
+
+        it('should not recognize the @externs tag', function() {
+            jasmine.getDocSetFromFile('test/fixtures/externstag.js');
+
+            expect(logger.error).toHaveBeenCalled();
+        });
+    });
+
+    describe('Closure Compiler tags', function() {
+        beforeEach(function() {
+            jasmine.replaceTagDictionary('closure');
+        });
+
+        it('should recognize the @externs tag', function() {
+            jasmine.getDocSetFromFile('test/fixtures/externstag.js');
+
+            expect(logger.error).not.toHaveBeenCalled();
+        });
+    });
+});