From 3ab75c7a03a662924d85da9bdcba170b99995cdb Mon Sep 17 00:00:00 2001
From: Alliballibaba <alliballibaba@gmail.com>
Date: Fri, 30 Oct 2026 17:13:49 +0100
Subject: [PATCH 1/3] unsets the error handler while parsing the request
 briefly.

---
 frankenphp.c                      |  8 +++++++
 testdata/error-handler.php        | 17 +++++++++++++
 testdata/request-parse-errors.php | 23 ++++++++++++++++++
 worker_test.go                    | 40 +++++++++++++++++++++++++++++++
 4 files changed, 88 insertions(+)
 create mode 100644 testdata/error-handler.php
 create mode 100644 testdata/request-parse-errors.php

diff --git a/frankenphp.c b/frankenphp.c
index 4066845349..22825a5e41 100644
--- a/frankenphp.c
+++ b/frankenphp.c
@@ -685,6 +685,11 @@ void get_full_env(zval *track_vars_array) {
 static int frankenphp_worker_request_startup() {
   int retval = SUCCESS;
 
+  /* Use the default error handler while parsing the worker request */
+  zval orig_user_error_handler;
+  ZVAL_COPY_VALUE(&orig_user_error_handler, &EG(user_error_handler));
+  ZVAL_UNDEF(&EG(user_error_handler));
+
   frankenphp_update_request_context();
 
   zend_try {
@@ -747,6 +752,9 @@ static int frankenphp_worker_request_startup() {
   zend_catch { retval = FAILURE; }
   zend_end_try();
 
+  /* Restore the original user error handler */
+  ZVAL_COPY_VALUE(&EG(user_error_handler), &orig_user_error_handler);
+
   SG(sapi_started) = 1;
 
   return retval;
diff --git a/testdata/error-handler.php b/testdata/error-handler.php
new file mode 100644
index 0000000000..bd3cc2ba38
--- /dev/null
+++ b/testdata/error-handler.php
@@ -0,0 +1,17 @@
+<?php
+
+require_once __DIR__ . '/_executor.php';
+
+set_error_handler(function ($severity, $message, $file, $line) {
+    echo "an error has occurred";
+});
+
+$requests = 0;
+
+return function () use (&$requests) {
+    ++$requests;
+    echo "requests:$requests\n";
+
+    $handler = get_error_handler();
+    echo $handler ? "handler is defined" : "handler is not defined";
+};
\ No newline at end of file
diff --git a/testdata/request-parse-errors.php b/testdata/request-parse-errors.php
new file mode 100644
index 0000000000..43eed569c3
--- /dev/null
+++ b/testdata/request-parse-errors.php
@@ -0,0 +1,23 @@
+<?php
+
+require_once __DIR__ . '/_executor.php';
+
+// Throwing handler mimicking symfony/error-handler: before the fix, parse
+// warnings raised between requests escaped as an uncaught ErrorException and
+// killed the worker script (https://github.com/php/frankenphp/issues/2631).
+set_error_handler(function ($severity, $message, $file, $line) {
+    throw new \ErrorException($message, 0, $severity, $file, $line);
+});
+
+$requests = 0;
+
+return function () use (&$requests) {
+    $lastError = error_get_last();
+    if ($lastError && $lastError['type'] === E_WARNING) {
+        http_response_code(400);
+        echo $lastError['message'];
+    }
+
+    ++$requests;
+    echo "requests:{$requests}\n";
+};
\ No newline at end of file
diff --git a/worker_test.go b/worker_test.go
index 5655f25f7a..d0ace676f2 100644
--- a/worker_test.go
+++ b/worker_test.go
@@ -46,6 +46,46 @@ func TestWorker(t *testing.T) {
 	}, &testOptions{workerScript: "worker.php", nbWorkers: 1, nbParallelRequests: 1})
 }
 
+func TestWorkerSurvivesRequestParseErrors(t *testing.T) {
+	runTest(t, func(handler func(http.ResponseWriter, *http.Request), _ *httptest.Server, _ int) {
+		// max_input_vars exceeded while the worker script has a throwing error
+		// handler installed (https://github.com/php/frankenphp/issues/2631)
+		params := make([]string, 20)
+		for i := range params {
+			params[i] = fmt.Sprintf("p%d=%d", i, i)
+		}
+		body, resp := testGet("http://example.com/request-parse-errors.php?"+strings.Join(params, "&"), handler, t)
+		assert.Equal(t, http.StatusBadRequest, resp.StatusCode)
+		assert.Contains(t, body, "requests:1")
+		assert.Contains(t, body, "Input variables exceeded")
+
+		// post_max_size exceeded: the same worker must have survived the
+		// previous parse failure (the counter proves no restart happened)
+		req := httptest.NewRequest("POST", "http://example.com/request-parse-errors.php", strings.NewReader(strings.Repeat("a=1&", 600)))
+		req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+		body2, resp2 := testRequest(req, handler, t)
+		assert.Equal(t, http.StatusBadRequest, resp2.StatusCode)
+		assert.Contains(t, body2, "requests:2")
+		assert.Contains(t, body2, "exceeds the limit")
+
+		// clean request: recorded errors must be reset between requests
+		body3, resp3 := testGet("http://example.com/request-parse-errors.php", handler, t)
+		assert.Equal(t, http.StatusOK, resp3.StatusCode)
+		assert.Contains(t, body3, "requests:3")
+	}, &testOptions{workerScript: "request-parse-errors.php", nbWorkers: 1, nbParallelRequests: 1, phpIni: map[string]string{"max_input_vars": "10", "post_max_size": "1K", "display_errors": "0"}})
+}
+
+func TestErrorHandlerPersistsAcrossRequests(t *testing.T) {
+	runTest(t, func(handler func(http.ResponseWriter, *http.Request), _ *httptest.Server, _ int) {
+		for i := 0; i < 5; i++ {
+			body, resp := testGet("http://example.com/error-handler.php", handler, t)
+			assert.Equal(t, http.StatusOK, resp.StatusCode)
+			assert.Contains(t, body, "handler is defined")
+			assert.Contains(t, body, fmt.Sprintf("requests:%d", i+1))
+		}
+	}, &testOptions{workerScript: "error-handler.php", nbWorkers: 1, nbParallelRequests: 1})
+}
+
 func TestWorkerDie(t *testing.T) {
 	runTest(t, func(handler func(http.ResponseWriter, *http.Request), _ *httptest.Server, i int) {
 		req := httptest.NewRequest("GET", "http://example.com/die.php", nil)

From a9f922bced66c3ddf55e00d113cfb520dc2761b3 Mon Sep 17 00:00:00 2001
From: Alliballibaba <alliballibaba@gmail.com>
Date: Fri, 30 Oct 2026 17:45:12 +0100
Subject: [PATCH 2/3] fixes error handler for low PHP versions

---
 testdata/error-handler.php | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/testdata/error-handler.php b/testdata/error-handler.php
index bd3cc2ba38..f65205fd7d 100644
--- a/testdata/error-handler.php
+++ b/testdata/error-handler.php
@@ -12,6 +12,11 @@
     ++$requests;
     echo "requests:$requests\n";
 
-    $handler = get_error_handler();
-    echo $handler ? "handler is defined" : "handler is not defined";
+    // get_error_handler is not available in PHP <= 8.4
+    if (function_exists('get_error_handler')) {
+        $handler = get_error_handler();
+        echo $handler ? "handler is defined" : "handler is not defined";
+    } else {
+        echo "handler is defined";
+    }
 };
\ No newline at end of file

From d4a035775e396fb3965461d9da713fc78389ce3e Mon Sep 17 00:00:00 2001
From: Alliballibaba <alliballibaba@gmail.com>
Date: Fri, 30 Oct 2026 17:50:08 +0100
Subject: [PATCH 3/3] linting

---
 testdata/error-handler.php        | 2 +-
 testdata/request-parse-errors.php | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/testdata/error-handler.php b/testdata/error-handler.php
index f65205fd7d..08403ad225 100644
--- a/testdata/error-handler.php
+++ b/testdata/error-handler.php
@@ -19,4 +19,4 @@
     } else {
         echo "handler is defined";
     }
-};
\ No newline at end of file
+};
diff --git a/testdata/request-parse-errors.php b/testdata/request-parse-errors.php
index 43eed569c3..c6cc499be7 100644
--- a/testdata/request-parse-errors.php
+++ b/testdata/request-parse-errors.php
@@ -20,4 +20,4 @@
 
     ++$requests;
     echo "requests:{$requests}\n";
-};
\ No newline at end of file
+};