Load environment resources when running help. (#1288)

Author: mshima

lib/index.js

@@ -189,19 +189,28 @@ class Generator extends Base {
     });
 
     this.env = this.options.env;
-    if (!this.env) {
-      throw new Error('This generator requires an environment.');
-    }
 
     this.resolved = this.options.resolved || __dirname;
     this.description = this.description || '';
 
-    // Determine the app root
-    this.contextRoot = this.env.cwd;
-    this.destinationRoot(this.options.destinationRoot || this.env.cwd);
+    if (this.env) {
+      // Determine the app root
+      this.contextRoot = this.env.cwd;
+      this.destinationRoot(this.options.destinationRoot || this.env.cwd);
+
+      // Ensure source/destination path, can be configured from subclasses
+      this.sourceRoot(path.join(path.dirname(this.resolved), 'templates'));
 
-    // Ensure source/destination path, can be configured from subclasses
-    this.sourceRoot(path.join(path.dirname(this.resolved), 'templates'));
+      this.fs = this.env.fs;
+    }
+
+    // Add convenience debug object
+    this._debug = createDebug(
+      this.options.namespace || 'yeoman:unknownnamespace'
+    );
+
+    // Expose utilities for dependency-less generators.
+    this._ = _;
 
     if (this.options.help) {
       return;
@@ -232,8 +241,13 @@ class Generator extends Base {
       this.features.uniqueBy = uniqueBy;
     }
 
+    if (!this.env) {
+      throw new Error('This generator requires an environment.');
+    }
+
     // Ensure the environment support features this yeoman-generator version require.
     if (
+      !this.env ||
       !this.env.adapter ||
       !this.env.runLoop ||
       !this.env.sharedFs ||
@@ -244,22 +258,15 @@ class Generator extends Base {
       );
     }
 
-    this.fs = this.env.fs;
-
-    // Place holder for run-async callback.
-    this.async = () => () => {};
-
     // Mirror the adapter log method on the generator.
     //
     // example:
     // this.log('foo');
     // this.log.error('bar');
-    this.log = this.env.adapter.log;
+    this.log = this.env.adapter && this.env.adapter.log;
 
-    // Add convenience debug object
-    this._debug = createDebug(
-      this.options.namespace || 'yeoman:unknownnamespace'
-    );
+    // Place holder for run-async callback.
+    this.async = () => () => {};
 
     this.appname = this.determineAppname();
 
@@ -292,9 +299,6 @@ class Generator extends Base {
 
     this.compose = this.options.compose;
 
-    // Expose utilities for dependency-less generators.
-    this._ = _;
-
     // Requires environment 3
     if (!this.options.skipCheckEnv) {
       this.checkEnvironmentVersion('3.0.0');

test/base.js

@@ -130,6 +130,35 @@ describe('Base', () => {
 
       assert(generator.fs);
     });
+
+    it('setup required fields for a working generator for help', function () {
+      const generator = new Base([], {
+        env: this.env,
+        help: true,
+        resolved: 'test'
+      });
+
+      assert(generator.env);
+      assert(generator.fs);
+      assert(generator._debug);
+      assert(generator._);
+
+      generator.option('foo');
+      generator.argument('baz');
+    });
+
+    it('should not fail without an env for help', () => {
+      const generator = new Base([], {
+        help: true,
+        resolved: 'test'
+      });
+
+      assert(generator._debug);
+      assert(generator._);
+
+      generator.option('foo');
+      generator.argument('baz');
+    });
   });
 
   describe('prototype', () => {