Expose Graph information for pluginContext calls (#2565)

* Expose graph module information for plugins.

* Refactor plugin module information and add test

* Add test that early access to moduleIds and module information is handled gracefully

src/rollup/types.d.ts

@@ -102,6 +102,14 @@ export interface PluginContext {
 	getAssetFileName: (assetId: string) => string;
 	warn(warning: RollupWarning | string, pos?: { line: number; column: number }): void;
 	error(err: RollupError | string, pos?: { line: number; column: number }): void;
+	moduleIds: IterableIterator<string>;
+	getModuleInfo: (
+		moduleId: string
+	) => {
+		id: string;
+		isExternal: boolean;
+		importedIds: string[];
+	};
 }
 
 export interface PluginContextMeta {

src/utils/pluginDriver.ts

@@ -1,5 +1,6 @@
 import { version as rollupVersion } from 'package.json';
 import Graph from '../Graph';
+import Module from '../Module';
 import {
 	InputOptions,
 	Plugin,
@@ -114,6 +115,21 @@ export function createPluginDriver(
 				warning.plugin = plugin.name || '(anonymous plugin)';
 				graph.warn(warning);
 			},
+			moduleIds: graph.moduleById.keys(),
+			getModuleInfo: (moduleId: string) => {
+				const foundModule = graph.moduleById.get(moduleId);
+				if (foundModule == null) {
+					throw new Error(`Unable to find module ${moduleId}`);
+				}
+
+				return {
+					id: foundModule.id,
+					isExternal: !!foundModule.isExternal,
+					importedIds: foundModule.isExternal
+						? []
+						: (foundModule as Module).sources.map(id => (foundModule as Module).resolvedIds[id])
+				};
+			},
 			watcher
 		};
 		return context;

test/form/samples/transform-bundle-plugin-options/_config.js

@@ -6,8 +6,10 @@ module.exports = {
 		plugins: [
 			{
 				transformBundle(code, options) {
-					console.log(Object.keys(options));
-					assert.strictEqual(Object.keys(options).join(', '), require('../../../misc/optionList').output);
+					assert.strictEqual(
+						Object.keys(options).join(', '),
+						require('../../../misc/optionList').output
+					);
 					return options.format;
 				}
 			}

test/function/samples/plugin-module-information-early-access/_config.js

@@ -0,0 +1,26 @@
+const assert = require('assert');
+const path = require('path');
+
+const ID_MAIN = path.join(__dirname, 'main.js');
+
+module.exports = {
+	description: 'handles accessing module information via plugins early in a graceful way',
+	options: {
+		external: ['path'],
+		plugins: [
+			{
+				buildStart() {
+					assert.deepEqual(Array.from(this.moduleIds), []);
+					// should throw "not found" error
+					this.getModuleInfo(ID_MAIN);
+				}
+			}
+		]
+	},
+	error: {
+		code: 'PLUGIN_ERROR',
+		hook: 'buildStart',
+		message: `Unable to find module ${ID_MAIN}`,
+		plugin: 'Plugin at pos 0'
+	}
+};

test/function/samples/plugin-module-information-early-access/main.js

@@ -0,0 +1 @@
+export default 42;

test/function/samples/plugin-module-information/_config.js

@@ -0,0 +1,47 @@
+const assert = require('assert');
+const path = require('path');
+
+const ID_MAIN = path.join(__dirname, 'main.js');
+const ID_FOO = path.join(__dirname, 'foo.js');
+const ID_NESTED = path.join(__dirname, 'nested', 'nested.js');
+const ID_PATH = 'path';
+
+let rendered = false;
+
+module.exports = {
+	description: 'provides module information on the plugin context',
+	options: {
+		external: ['path'],
+		plugins: [
+			{
+				renderStart() {
+					rendered = true;
+					assert.deepEqual(Array.from(this.moduleIds), [ID_MAIN, ID_FOO, ID_NESTED, ID_PATH]);
+					assert.deepEqual(this.getModuleInfo(ID_MAIN), {
+						id: ID_MAIN,
+						importedIds: [ID_FOO, ID_NESTED],
+						isExternal: false
+					});
+					assert.deepEqual(this.getModuleInfo(ID_FOO), {
+						id: ID_FOO,
+						importedIds: [ID_PATH],
+						isExternal: false
+					});
+					assert.deepEqual(this.getModuleInfo(ID_NESTED), {
+						id: ID_NESTED,
+						importedIds: [ID_FOO],
+						isExternal: false
+					});
+					assert.deepEqual(this.getModuleInfo(ID_PATH), {
+						id: ID_PATH,
+						importedIds: [],
+						isExternal: true
+					});
+				}
+			}
+		]
+	},
+	bundle() {
+		assert.ok(rendered);
+	}
+};

test/function/samples/plugin-module-information/foo.js

@@ -0,0 +1,3 @@
+import path from 'path';
+
+export const foo = path.resolve('foo');

test/function/samples/plugin-module-information/main.js

@@ -0,0 +1,4 @@
+export {foo} from './foo.js';
+import { nested } from './nested/nested';
+
+export {nested};

test/function/samples/plugin-module-information/nested/nested.js

@@ -0,0 +1,3 @@
+import { foo } from '../foo.js';
+
+export const nested = 'nested' + foo;