Do not fail when generating hashes for tree-shaken dynamic imports

src/Chunk.ts

@@ -132,7 +132,7 @@ export default class Chunk {
 	} = undefined;
 	private renderedHash: string = undefined;
 	private renderedModuleSources: MagicString[] = undefined;
-	private renderedSource: MagicStringBundle = undefined;
+	private renderedSource: MagicStringBundle | null = null;
 	private renderedSourceLength: number = undefined;
 
 	constructor(graph: Graph, orderedModules: Module[], inlineDynamicImports: boolean) {
@@ -662,8 +662,9 @@ export default class Chunk {
 		return exports;
 	}
 
-	getRenderedHash() {
+	getRenderedHash(): string {
 		if (this.renderedHash) return this.renderedHash;
+		if (!this.renderedSource) return '';
 		const hash = sha256();
 		hash.update(this.renderedSource.toString());
 		return (this.renderedHash = hash.digest('hex'));

test/chunking-form/samples/tree-shaken-dynamic-hash/_config.js

@@ -0,0 +1,10 @@
+module.exports = {
+	description:
+		'Does not fail when calculating the hash of a file containing a tree-shaken dynamic import',
+	options: {
+		input: ['main.js'],
+		output: {
+			entryFileNames: '[hash].js'
+		}
+	}
+};

test/chunking-form/samples/tree-shaken-dynamic-hash/_expected/amd/5654511d.js

@@ -0,0 +1,7 @@
+define(function () { 'use strict';
+
+	var main = null;
+
+	return main;
+
+});

test/chunking-form/samples/tree-shaken-dynamic-hash/_expected/cjs/69b0b1f3.js

@@ -0,0 +1,5 @@
+'use strict';
+
+var main = null;
+
+module.exports = main;

test/chunking-form/samples/tree-shaken-dynamic-hash/_expected/es/21d179d7.js

@@ -0,0 +1,3 @@
+var main = null;
+
+export default main;

test/chunking-form/samples/tree-shaken-dynamic-hash/_expected/system/8714c598.js

@@ -0,0 +1,10 @@
+System.register([], function (exports, module) {
+	'use strict';
+	return {
+		execute: function () {
+
+			var main = exports('default', null);
+
+		}
+	};
+});

test/chunking-form/samples/tree-shaken-dynamic-hash/foo.js

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

test/chunking-form/samples/tree-shaken-dynamic-hash/main.js

@@ -0,0 +1,3 @@
+export default false
+	? import('./foo.js')
+	: null;