Merge pull request #10185 from webpack/bugfix/non-deterministic-provided-exports

make order of exports in providedExports deterministic

lib/FlagDependencyExportsPlugin.js

@@ -7,14 +7,11 @@
 const Queue = require("./util/Queue");
 
 const addToSet = (a, b) => {
-	let changed = false;
+	const size = a.size;
 	for (const item of b) {
-		if (!a.has(item)) {
-			a.add(item);
-			changed = true;
-		}
+		a.add(item);
 	}
-	return changed;
+	return a.size !== size;
 };
 
 class FlagDependencyExportsPlugin {
@@ -114,11 +111,7 @@ class FlagDependencyExportsPlugin {
 							if (module.buildMeta.providedExports !== true) {
 								moduleWithExports =
 									module.buildMeta && module.buildMeta.exportsType;
-								moduleProvidedExports = Array.isArray(
-									module.buildMeta.providedExports
-								)
-									? new Set(module.buildMeta.providedExports)
-									: new Set();
+								moduleProvidedExports = new Set();
 								providedExportsAreTemporary = false;
 								processDependenciesBlock(module);
 								module.buildInfo.temporaryProvidedExports = providedExportsAreTemporary;

test/hotCases/determinism/issue-10174/deps/a.js

@@ -0,0 +1 @@
+export * from './b'

test/hotCases/determinism/issue-10174/deps/b.js

@@ -0,0 +1,5 @@
+export * from './c'
+
+export function b() {
+  // this extra export is needed for the issue to reproduce
+}

test/hotCases/determinism/issue-10174/deps/c.js

@@ -0,0 +1,3 @@
+export function c() {
+	return 42;
+}

test/hotCases/determinism/issue-10174/hot.js

@@ -0,0 +1,3 @@
+export default 1;
+---
+export default 2;

test/hotCases/determinism/issue-10174/index.js

@@ -0,0 +1,14 @@
+import { c } from "./deps/a";
+import hot from "./hot";
+
+it("should only register changes for the changed module", done => {
+	expect(hot).toBe(1);
+	expect(c()).toBe(42);
+	module.hot.accept("./hot", () => {
+		expect(hot).toBe(2);
+		expect(c()).toBe(42);
+		done();
+	});
+
+	NEXT(require("../../update")(done));
+});