fix: ignore duplicated module (#191)

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##### Checklist
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[x]. -->

- [ ] `npm test` passes
- [ ] tests and/or benchmarks are included
- [ ] documentation is changed or added
- [ ] commit message follows commit guidelines

##### Affected core subsystem(s)
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##### Description of change
<!-- Provide a description of the change below this comment. -->

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- any feature?
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.gitignore

@@ -41,3 +41,4 @@ plugin/tegg/test/fixtures/apps/**/*.js
 !standalone/standalone/test/fixtures/**/node_modules
 !standalone/standalone/test/fixtures/**/node_modules/**/*.js
 !plugin/tegg/test/fixtures/**/node_modules
+!plugin/config/test/fixtures/**/node_modules

plugin/config/lib/ModuleScanner.ts

@@ -28,14 +28,17 @@ export class ModuleScanner {
     });
     const frameworkDir = path.dirname(frameworkPkg);
     const optionalModuleReferences = ModuleConfigUtil.readModuleReference(frameworkDir, this.readModuleOptions || {});
-    return [
+    const result = [
       ...moduleReferences,
-      ...optionalModuleReferences.map(t => {
-        return {
-          ...t,
-          optional: true,
-        };
-      }),
     ];
+    for (const optionalModuleReference of optionalModuleReferences) {
+      if (!result.some(t => t.path === optionalModuleReference.path)) {
+        result.push({
+          ...optionalModuleReference,
+          optional: true,
+        });
+      }
+    }
+    return result;
   }
 }

plugin/config/test/DuplicateOptionalModule.test.ts

@@ -0,0 +1,32 @@
+import mm from 'egg-mock';
+import assert from 'assert';
+import path from 'path';
+
+describe('test/DuplicateOptionalModule.test.ts', () => {
+  let app;
+  const fixturesPath = path.join(__dirname, './fixtures/apps/duplicate-optional-module');
+
+  after(async () => {
+    await app.close();
+  });
+
+  afterEach(() => {
+    mm.restore();
+  });
+
+  before(async () => {
+    mm(process.env, 'EGG_TYPESCRIPT', true);
+    mm(process, 'cwd', () => {
+      return path.join(__dirname, '..');
+    });
+    app = mm.app({
+      baseDir: fixturesPath,
+      framework: require.resolve('egg'),
+    });
+    await app.ready();
+  });
+
+  it('should work', async () => {
+    assert.equal(app.moduleReferences.length, 2);
+  });
+});

plugin/config/test/fixtures/apps/duplicate-optional-module/config/config.default.js

@@ -0,0 +1,20 @@
+'use strict';
+
+const path = require('path');
+
+module.exports = function(appInfo) {
+  const config = {
+    keys: 'test key',
+    customLogger: {
+      xxLogger: {
+        file: path.join(appInfo.root, 'logs/xx.log'),
+      },
+    },
+    security: {
+      csrf: {
+        ignoreJSON: false,
+      }
+    },
+  };
+  return config;
+};

plugin/config/test/fixtures/apps/duplicate-optional-module/config/plugin.js

@@ -0,0 +1,8 @@
+'use strict';
+
+exports.tracer = {
+  package: 'egg-tracer',
+  enable: true,
+};
+
+exports.watcher = false;

plugin/config/test/fixtures/apps/duplicate-optional-module/package.json

@@ -0,0 +1,9 @@
+{
+  "name": "egg-app",
+  "egg": {
+    "framework": "foo"
+  },
+  "dependencies": {
+    "used": "*"
+  }
+}