From ab981e2c0a6da409957a111e2f4b2df8124d4e80 Mon Sep 17 00:00:00 2001
From: "microsoft-playwright-automation[bot]"
 <203992400+microsoft-playwright-automation[bot]@users.noreply.github.com>
Date: Mon, 21 Sep 2026 21:03:44 +0000
Subject: [PATCH] feat(firefox): roll to r1551

---
 .../firefox/juggler/NetworkObserver.js        | 36 ++++++++++++++-----
 .../firefox/juggler/content/main.js           |  2 +-
 packages/playwright-core/browsers.json        |  2 +-
 3 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/browser_patches/firefox/juggler/NetworkObserver.js b/browser_patches/firefox/juggler/NetworkObserver.js
index bc4428b996d24..e2e4f1993e07e 100644
--- a/browser_patches/firefox/juggler/NetworkObserver.js
+++ b/browser_patches/firefox/juggler/NetworkObserver.js
@@ -553,7 +553,7 @@ class NetworkRequest {
       responseStart: this.httpChannel.responseStartTime,
     };
 
-    const { status, statusText, headers } = responseHead(this.httpChannel, opt_statusCode, opt_statusText);
+    const { status, statusText, headers } = responseHead(this.httpChannel, fromCache, opt_statusCode, opt_statusText);
     if (redirectStatus.includes(status) && this._overriddenHeadersForRedirect)
       this._overriddenHeadersForRedirect = filterHeadersForRedirect(this._overriddenHeadersForRedirect, this.httpChannel.requestMethod, status);
     let remoteIPAddress = undefined;
@@ -968,19 +968,39 @@ class ResponseStorage {
   }
 }
 
-function responseHead(httpChannel, opt_statusCode, opt_statusText) {
-  const headers = [];
+function responseHead(httpChannel, fromCache, opt_statusCode, opt_statusText) {
+  let headers = [];
   let status = opt_statusCode || 0;
   let statusText = opt_statusText || '';
   try {
     status = httpChannel.responseStatus;
     statusText = httpChannel.responseStatusText;
-    httpChannel.visitResponseHeaders({
-      visitHeader: (name, value) => headers.push({name, value}),
-    });
   } catch (e) {
-    // Response headers, status and/or statusText are not available
-    // when redirect did not actually hit the network.
+    if (e.result !== Cr.NS_ERROR_NOT_AVAILABLE)
+      console.error('Failed to read response status', e);
+    return { status, statusText, headers };
+  }
+  const visitor = {
+    visitHeader: (name, value) => headers.push({name, value}),
+  };
+  // Responses are cached after cookies and authentication headers are revalidated/pruned.
+  // As such, do not use the original headers as that may not reflect what was actually used.
+  if (!fromCache) {
+    try {
+      httpChannel.visitOriginalResponseHeaders(visitor);
+    } catch (e) {
+      if (e.result !== Cr.NS_ERROR_NOT_AVAILABLE)
+        console.error('Failed to read original response headers', e);
+      headers = [];
+    }
+  }
+  if (!headers.length) {
+    try {
+      httpChannel.visitResponseHeaders(visitor);
+    } catch (e) {
+      if (e.result !== Cr.NS_ERROR_NOT_AVAILABLE)
+        console.error('Failed to read response headers', e);
+    }
   }
   return { status, statusText, headers };
 }
diff --git a/browser_patches/firefox/juggler/content/main.js b/browser_patches/firefox/juggler/content/main.js
index 8028692f876ce..5842ed8fb23ed 100644
--- a/browser_patches/firefox/juggler/content/main.js
+++ b/browser_patches/firefox/juggler/content/main.js
@@ -61,7 +61,7 @@ export function initialize(browsingContext, docShell) {
   for (const { worldName, name, script } of [...contextCrossProcessCookie.bindings, ...pageCrossProcessCookie.bindings])
     data.frameTree.addBinding(worldName, name, script);
   data.frameTree.setInitScripts([...contextCrossProcessCookie.initScripts, ...pageCrossProcessCookie.initScripts]);
-  data.channel = new SimpleChannel('', 'process-' + Services.appinfo.processID);
+  data.channel = new SimpleChannel('', 'process-' + Services.appinfo.processID + '-' + helper.generateId());
   data.pageAgent = new PageAgent(data.channel, data.frameTree);
   docShell.fileInputInterceptionEnabled = !!pageCrossProcessCookie.interceptFileChooserDialog;
 
diff --git a/packages/playwright-core/browsers.json b/packages/playwright-core/browsers.json
index 45dd907b98c57..94d8286f2622a 100644
--- a/packages/playwright-core/browsers.json
+++ b/packages/playwright-core/browsers.json
@@ -17,7 +17,7 @@
     },
     {
       "name": "firefox",
-      "revision": "1549",
+      "revision": "1551",
       "installByDefault": true,
       "browserVersion": "156.0",
       "title": "Firefox"