From cefcfa09a9d3ce4636bc2006be9de9b856a0ca6a Mon Sep 17 00:00:00 2001
From: Henning Dieterichs <hdieterichs@microsoft.com>
Date: Fri, 8 May 2026 16:32:18 +0200
Subject: [PATCH] Limit error message header to first line

---
 build/lib/screenshotDiffReport.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/build/lib/screenshotDiffReport.ts b/build/lib/screenshotDiffReport.ts
index 1176ab80236..dfbcee8b53a 100644
--- a/build/lib/screenshotDiffReport.ts
+++ b/build/lib/screenshotDiffReport.ts
@@ -424,7 +424,8 @@ function generateMarkdown(
 		for (let i = 0; i < errored.length; i++) {
 			const entry = errored[i];
 			const open = i < EXPAND_FIRST_N ? ' open' : '';
-			const header = `<details${open}><summary><code>${entry.fixtureId}</code> — ${escapeMarkdown(entry.errorMessage)}</summary>`;
+			const headerMessage = entry.errorMessage.split('\n').map(l => l.trim()).find(l => l.length > 0) ?? entry.errorMessage;
+			const header = `<details${open}><summary><code>${entry.fixtureId}</code> — ${escapeMarkdown(headerMessage)}</summary>`;
 			const fullStack = entry.errorStack ?? entry.errorMessage;
 			const fullBlock = `${header}\n\n\`\`\`\n${fullStack}\n\`\`\`\n\n</details>\n`;