From acd624036eafe88400c1cd7239cb6fb8c6f59548 Mon Sep 17 00:00:00 2001
From: Lukas Taegert-Atkinson <lukas.taegert-atkinson@tngtech.com>
Date: Tue, 18 Oct 2022 06:22:09 +0200
Subject: [PATCH] Return correct values for unkown namespace members

---
 src/ast/variables/NamespaceVariable.ts              | 13 +++++++++----
 .../samples/namespace-literal-value/_config.js      |  9 +++++++++
 .../samples/namespace-literal-value/main.js         |  3 +++
 .../samples/namespace-literal-value/namespace.js    |  2 ++
 4 files changed, 23 insertions(+), 4 deletions(-)
 create mode 100644 test/function/samples/namespace-literal-value/_config.js
 create mode 100644 test/function/samples/namespace-literal-value/main.js
 create mode 100644 test/function/samples/namespace-literal-value/namespace.js

diff --git a/src/ast/variables/NamespaceVariable.ts b/src/ast/variables/NamespaceVariable.ts
index 207bbec7b13..a410983d5bf 100644
--- a/src/ast/variables/NamespaceVariable.ts
+++ b/src/ast/variables/NamespaceVariable.ts
@@ -1,11 +1,14 @@
-import type { AstContext } from '../../Module';
 import type Module from '../../Module';
+import type { AstContext } from '../../Module';
 import { getToStringTagValue, MERGE_NAMESPACES_VARIABLE } from '../../utils/interopHelpers';
 import type { RenderOptions } from '../../utils/renderHelpers';
 import { getSystemExportStatement } from '../../utils/systemJsRendering';
 import type Identifier from '../nodes/Identifier';
 import type { LiteralValueOrUnknown } from '../nodes/shared/Expression';
+import { UnknownValue } from '../nodes/shared/Expression';
 import type ChildScope from '../scopes/ChildScope';
+import type { ObjectPath } from '../utils/PathTracker';
+import { SymbolToStringTag } from '../utils/PathTracker';
 import Variable from './Variable';
 
 export default class NamespaceVariable extends Variable {
@@ -29,9 +32,11 @@ export default class NamespaceVariable extends Variable {
 		this.name = identifier.name;
 	}
 
-	getLiteralValueAtPath(): LiteralValueOrUnknown {
-		// This can only happen for Symbol.toStringTag right now
-		return 'Module';
+	getLiteralValueAtPath(path: ObjectPath): LiteralValueOrUnknown {
+		if (path[0] === SymbolToStringTag) {
+			return 'Module';
+		}
+		return UnknownValue;
 	}
 
 	getMemberVariables(): { [name: string]: Variable } {
diff --git a/test/function/samples/namespace-literal-value/_config.js b/test/function/samples/namespace-literal-value/_config.js
new file mode 100644
index 00000000000..8ad52a0cd78
--- /dev/null
+++ b/test/function/samples/namespace-literal-value/_config.js
@@ -0,0 +1,9 @@
+const assert = require('node:assert');
+
+module.exports = {
+	description: 'does not simplify accessing unknown properties from namespaces',
+	exports({ isNull }) {
+		assert.strictEqual(isNull('a'), true);
+		assert.strictEqual(isNull('b'), false);
+	}
+};
diff --git a/test/function/samples/namespace-literal-value/main.js b/test/function/samples/namespace-literal-value/main.js
new file mode 100644
index 00000000000..8eee5b022ea
--- /dev/null
+++ b/test/function/samples/namespace-literal-value/main.js
@@ -0,0 +1,3 @@
+import * as ns from './namespace';
+
+export const isNull = prop => (ns[prop] === null ? true : false);
diff --git a/test/function/samples/namespace-literal-value/namespace.js b/test/function/samples/namespace-literal-value/namespace.js
new file mode 100644
index 00000000000..1d944cff982
--- /dev/null
+++ b/test/function/samples/namespace-literal-value/namespace.js
@@ -0,0 +1,2 @@
+export const a = null;
+export const b = true;