AG-27143 Fix issue with setting values to wrong properties in set-con…

…stant scriptlet. #373

Squashed commit of the following:

commit b4fb774
Merge: 751872d 0605d92
Author: Adam Wróblewski <adam@adguard.com>
Date:   Fri Oct 27 15:41:18 2023 +0200

    Merge branch 'master' into fix/AG-27143

commit 751872d
Author: Adam Wróblewski <adam@adguard.com>
Date:   Fri Oct 27 07:42:15 2023 +0200

    Update tests
    Remove global properties after tests

commit d1a58f9
Author: Adam Wróblewski <adam@adguard.com>
Date:   Thu Oct 26 21:28:05 2023 +0200

    Fix issue with setting values to wrong properties in set-constant scriptlet

CHANGELOG.md

@@ -7,6 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 <!-- TODO: add @added tag to the files with specific version -->
 <!--       during new scriptlets or redirects releasing -->
 
+## [Unreleased]
+
+### Fixed
+
+- issue with setting values to wrong properties in `set-constant` scriptlet
+  [#373](https://github.com/AdguardTeam/Scriptlets/issues/373)
+
 ## [v1.9.83] - 2023-10-13
 
 ### Added
@@ -266,6 +273,7 @@ prevent inline `onerror` and match `link` tag [#276](https://github.com/AdguardT
     - `metrika-yandex-tag` [#254](https://github.com/AdguardTeam/Scriptlets/issues/254)
     - `googlesyndication-adsbygoogle` [#252](https://github.com/AdguardTeam/Scriptlets/issues/252)
 
+[Unreleased]: https://github.com/AdguardTeam/Scriptlets/compare/v1.9.83...HEAD
 [v1.9.83]: https://github.com/AdguardTeam/Scriptlets/compare/v1.9.72...v1.9.83
 [v1.9.72]: https://github.com/AdguardTeam/Scriptlets/compare/v1.9.70...v1.9.72
 [v1.9.70]: https://github.com/AdguardTeam/Scriptlets/compare/v1.9.62...v1.9.70

src/scriptlets/set-constant.js

@@ -271,7 +271,10 @@ export function setConstant(source, property, value, stack = '', valueWrapper =
                 return false;
             }
 
-            base[prop] = constantValue;
+            if (base[prop]) {
+                base[prop] = constantValue;
+            }
+
             if (origDescriptor.set instanceof Function) {
                 prevSetter = origDescriptor.set;
             }

tests/scriptlets/set-constant.test.js

@@ -752,4 +752,47 @@ if (!isSupported) {
         // eslint-disable-next-line max-len
         assert.strictEqual(window.ads.videoAd.loadModule(), true, 'ads.videoAd.loadModule was set to function which returns true');
     });
+
+    test('Test for reassignment 1', (assert) => {
+        runScriptletFromTag('zxcv.test.bar.qw', 'trueFunc');
+        const funcOne = () => 1;
+        window.zxcv = {};
+        // Reassign
+        window.zxcv = {};
+        window.zxcv.mnb = true;
+        window.zxcv.test = {
+            bar: {
+                qw: funcOne,
+            },
+        };
+        const result = window.zxcv.test.bar.qw();
+        assert.strictEqual(window.zxcv.mnb, true, 'redefined correctly');
+        assert.strictEqual(result, true, 'redefined correctly by scriptlet');
+        clearGlobalProps('zxcv');
+    });
+
+    test('Test for reassignment 2', (assert) => {
+        runScriptletFromTag('WO.adblock.useAdblocker', 'false');
+
+        window.WO = window.WO || {};
+        window.WO.strings = window.WO.strings || {};
+        // Reassign
+        window.WO = window.WO || {};
+        window.WO.strings = window.WO.strings || {};
+        window.WO.test = 1;
+        window.WO.adblock = {
+            useAdblocker: true,
+        };
+        assert.strictEqual(window.WO.test, 1, 'WO.test redefined correctly');
+        assert.strictEqual(window.WO.adblock.useAdblocker, false, 'WO.adblock.useAdblocker set to false by scriptlet');
+        clearGlobalProps('WO');
+    });
+
+    test('Should not set', (assert) => {
+        runScriptletFromTag('something.start.stop', 'false');
+
+        window.something = window.something || {};
+        assert.strictEqual(window.something.start, undefined, 'something.start was not set');
+        clearGlobalProps('something');
+    });
 }