Create a shallow copy when returning meta from resolveId (#4347)

src/Module.ts

@@ -293,7 +293,7 @@ export default class Module {
 				}
 				return module.isIncluded();
 			},
-			meta,
+			meta: { ...meta },
 			syntheticNamedExports
 		};
 	}

test/function/samples/reuse-resolve-meta/_config.js

@@ -0,0 +1,29 @@
+const assert = require('assert');
+const path = require('path');
+const meta = { plugin: { initial: true } };
+
+const ID_MAIN = path.join(__dirname, 'main.js');
+
+module.exports = {
+	description: 'does not modify meta objects passed in resolveId',
+	options: {
+		plugins: [
+			{
+				async resolveId(source, importer) {
+					const { id } = await this.resolve(source, importer, { skipSelf: true });
+					return { id, meta };
+				},
+				transform(code) {
+					return { code, meta: { otherPlugin: { ignored: true }, plugin: { replaced: true } } };
+				},
+				buildEnd() {
+					assert.deepStrictEqual(meta, { plugin: { initial: true } });
+					assert.deepStrictEqual(this.getModuleInfo(ID_MAIN).meta, {
+						otherPlugin: { ignored: true },
+						plugin: { replaced: true }
+					});
+				}
+			}
+		]
+	}
+};

test/function/samples/reuse-resolve-meta/main.js

@@ -0,0 +1 @@
+assert.ok(true);