From 21ae298015c2e53296dea03240439e0c8ca97934 Mon Sep 17 00:00:00 2001
From: Max Schmitt <max@schmitt.mx>
Date: Thu, 17 Feb 2022 22:12:42 +0100
Subject: [PATCH] fix(trace-viewer): don't crash when argument is null (#12186)

---
 .../src/web/traceViewer/ui/callTab.tsx          |  2 +-
 tests/trace-viewer/trace-viewer.spec.ts         | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/packages/playwright-core/src/web/traceViewer/ui/callTab.tsx b/packages/playwright-core/src/web/traceViewer/ui/callTab.tsx
index f2be96bee6..18efe7ceb9 100644
--- a/packages/playwright-core/src/web/traceViewer/ui/callTab.tsx
+++ b/packages/playwright-core/src/web/traceViewer/ui/callTab.tsx
@@ -82,7 +82,7 @@ function toString(metadata: CallMetadata, name: string, value: any): { title: st
       value = parseSerializedValue(value, new Array(10).fill({ handle: '<handle>' }));
   }
   const type = typeof value;
-  if (type !== 'object')
+  if (type !== 'object' || value === null)
     return { title: String(value), type };
   if (value.guid)
     return { title: '<handle>', type: 'handle' };
diff --git a/tests/trace-viewer/trace-viewer.spec.ts b/tests/trace-viewer/trace-viewer.spec.ts
index 18fa5dbd9e..b0d67b0420 100644
--- a/tests/trace-viewer/trace-viewer.spec.ts
+++ b/tests/trace-viewer/trace-viewer.spec.ts
@@ -145,6 +145,8 @@ test.beforeAll(async function recordTrace({ browser, browserName, browserType, s
     });
   }, { a: 'paramA', b: 4 });
 
+  await page.evaluate(() => 1 + 1, null);
+
   async function doClick() {
     await page.click('"Click"');
   }
@@ -192,6 +194,7 @@ test('should open simple trace viewer', async ({ showTraceViewer }) => {
     /page.setContent/,
     /expect.toHaveTextbutton/,
     /page.evaluate/,
+    /page.evaluate/,
     /page.click"Click"/,
     /page.waitForEvent/,
     /page.waitForEvent/,
@@ -254,6 +257,20 @@ test('should show params and return value', async ({ showTraceViewer, browserNam
   ]);
 });
 
+test('should show null as a param', async ({ showTraceViewer, browserName }) => {
+  const traceViewer = await showTraceViewer([traceFile]);
+  await traceViewer.selectAction('page.evaluate', 1);
+  await expect(traceViewer.callLines).toHaveText([
+    /page.evaluate/,
+    /wall time: [0-9/:,APM ]+/,
+    /duration: [\d]+ms/,
+    'expression: "() => 1 + 1"',
+    'isFunction: true',
+    'arg: null',
+    'value: 2'
+  ]);
+});
+
 test('should have correct snapshot size', async ({ showTraceViewer }, testInfo) => {
   const traceViewer = await showTraceViewer([traceFile]);
   await traceViewer.selectAction('page.setViewport');