✨ Autoload plugins

.github/workflows/test.yml

@@ -37,6 +37,7 @@ jobs:
           - '@percy/dom'
           - '@percy/config'
           - '@percy/core'
+          - '@percy/cli'
           - '@percy/cli-command'
           - '@percy/cli-exec'
           - '@percy/cli-snapshot'

packages/cli/bin/run

@@ -1,5 +1,5 @@
 #!/usr/bin/env node
 
-require('@oclif/command').run()
+require('@percy/cli').run()
   .then(require('@oclif/command/flush'))
   .catch(require('@oclif/errors/handle'))

packages/cli/index.js

@@ -1,2 +1,43 @@
-// This package is a multi-command oclif CLI composed of plugins that provide
-// various functionalities for taking Percy snapshots.
+const { promises: fs } = require('fs');
+const path = require('path');
+
+// find plugins in a directory, matching a regexp, ignoring registered plugins
+function findPlugins(dir, regexp, registered) {
+  return fs.readdir(dir).then(f => f.reduce((plugins, dirname) => {
+    if (dirname === 'cli' || !regexp.test(dirname)) return plugins;
+
+    let { name, oclif } = require(`${dir}/${dirname}/package.json`);
+
+    if (!registered.includes(name) && oclif && oclif.bin === 'percy') {
+      return plugins.concat(name);
+    } else {
+      return plugins;
+    }
+  }, []));
+}
+
+// automatically register/unregister plugins by altering the CLI's package.json within node_modules
+async function autoRegisterPlugins() {
+  let pkgPath = path.resolve(__dirname, 'package.json');
+  let pkg = require(pkgPath);
+
+  let registered = pkg.oclif.plugins.filter(plugin => {
+    if (pkg.dependencies[plugin]) return true;
+    try { return !!require.resolve(plugin); } catch {}
+    return false;
+  });
+
+  let unregistered = await Promise.all([
+    findPlugins(path.resolve(__dirname, '..'), /^.*/, registered), // @percy/*
+    findPlugins(path.resolve(__dirname, '../..'), /^percy-cli-.*/, registered) // percy-cli-*
+  ]).then(p => Array.from(new Set(p.flat())));
+
+  if (unregistered.length || registered.length !== pkg.oclif.plugins.length) {
+    pkg.oclif.plugins = registered.concat(unregistered);
+    await fs.writeFile(pkgPath, JSON.stringify(pkg, null, 2) + '\n');
+  }
+}
+
+// auto register plugins before running oclif
+module.exports.run = () => autoRegisterPlugins()
+  .then(() => require('@oclif/command').run());

packages/cli/package.json

@@ -16,11 +16,15 @@
   },
   "scripts": {
     "lint": "eslint --ignore-path ../../.gitignore .",
-    "postbuild": "oclif-dev manifest"
+    "test": "cross-env NODE_ENV=test mocha",
+    "test:coverage": "nyc yarn test"
   },
   "publishConfig": {
     "access": "public"
   },
+  "mocha": {
+    "require": "../../scripts/babel-register"
+  },
   "oclif": {
     "bin": "percy",
     "plugins": [
@@ -29,13 +33,11 @@
       "@percy/cli-build",
       "@percy/cli-snapshot",
       "@percy/cli-upload",
-      "@oclif/plugin-help",
-      "@oclif/plugin-plugins"
+      "@oclif/plugin-help"
     ]
   },
   "dependencies": {
     "@oclif/plugin-help": "^3.2.0",
-    "@oclif/plugin-plugins": "^1.9.0",
     "@percy/cli-build": "^1.0.0-beta.34",
     "@percy/cli-config": "^1.0.0-beta.34",
     "@percy/cli-exec": "^1.0.0-beta.34",

packages/cli/test/.eslintrc

@@ -0,0 +1,2 @@
+env:
+  mocha: true

packages/cli/test/helpers.js

@@ -0,0 +1,51 @@
+import path from 'path';
+import mockRequire from 'mock-require';
+
+export function pluginMocker() {
+  let pkgPath = path.resolve(__dirname, '../package.json');
+
+  let mock = ({ plugins, packages }) => {
+    for (let [name, dep] of Object.entries(plugins)) {
+      if (dep) mock.pkg.dependencies[name] = true;
+      mock.pkg.oclif.plugins.push(name);
+    }
+
+    for (let [name, plugin] of Object.entries(packages)) {
+      let dir = path.resolve(__dirname, name.startsWith('@percy') ? '../..' : '../../..');
+      let dirname = name.replace('@percy', '');
+
+      mock.dir[dir].push(dirname);
+      mockRequire(`${dir}/${dirname}/package.json`, plugin ? (
+        { name, oclif: { bin: 'percy' } }
+      ) : { name });
+    }
+  };
+
+  mock.pkg = {
+    oclif: { plugins: [] },
+    dependencies: {}
+  };
+
+  mock.dir = {
+    [path.resolve(__dirname, '../..')]: [],
+    [path.resolve(__dirname, '../../..')]: []
+  };
+
+  mockRequire(pkgPath, mock.pkg);
+  mockRequire('fs', {
+    ...require('fs'),
+
+    promises: {
+      readdir: async dir => mock.dir[dir],
+      writeFile: async (path, contents) => {
+        if (path === pkgPath) {
+          mock.pkg = JSON.parse(contents);
+        }
+      }
+    }
+  });
+
+  return mock;
+}
+
+export { mockRequire };

packages/cli/test/index.test.js

@@ -0,0 +1,80 @@
+import expect from 'expect';
+import { pluginMocker, mockRequire } from './helpers';
+
+describe('Plugin auto-registration', () => {
+  let mock, run;
+
+  beforeEach(() => {
+    mock = pluginMocker();
+    mockRequire('@oclif/command', { run() {} });
+    run = mockRequire.reRequire('..').run;
+  });
+
+  afterEach(() => {
+    mockRequire.stopAll();
+  });
+
+  it('adds unregistered plugins to the package.json', async () => {
+    mock({
+      plugins: {
+        '@percy/cli-exec': true
+      },
+      packages: {
+        '@percy/cli-config': true,
+        '@percy/cli-exec': true,
+        '@percy/core': false,
+        '@percy/storybook': true,
+        'percy-cli-custom': true,
+        'percy-cli-no': false,
+        'percy-custom': true
+      }
+    });
+
+    await run();
+
+    expect(mock.pkg.oclif.plugins).toEqual([
+      '@percy/cli-exec',
+      '@percy/cli-config',
+      '@percy/storybook',
+      'percy-cli-custom'
+    ]);
+  });
+
+  it('removes missing plugins from the package.json', async () => {
+    mock({
+      plugins: {
+        '@percy/cli-exec': true,
+        '@percy/cli-other': false
+      },
+      packages: {
+        '@percy/cli-exec': true
+      }
+    });
+
+    await run();
+
+    expect(mock.pkg.oclif.plugins).toEqual([
+      '@percy/cli-exec'
+    ]);
+  });
+
+  it('does nothing when plugins are registered', async () => {
+    mock({
+      plugins: {
+        '@percy/cli-exec': true,
+        '@percy/cli-other': true
+      },
+      packages: {
+        '@percy/cli-exec': true,
+        '@percy/cli-other': true
+      }
+    });
+
+    await run();
+
+    expect(mock.pkg.oclif.plugins).toEqual([
+      '@percy/cli-exec',
+      '@percy/cli-other'
+    ]);
+  });
+});