Fix single process crash when proxy pac is used

Using proxy v8 resolver ends up in race condition
when render thread tries to evaluate extension handle
and v8 proxy resolver evaluates proxy pac script.

Disable v8 proxy resolver for single process mode.
Issue tracked upstream http://crbug.com/474654

Modify the unit test to catch the crash case, the test
loads now network resource but it does not matter
as we do not check for failure or success.

Fixes: QTBUG-104436
Change-Id: Id3221d1b8b3896f0ced3d0cd7cb9d9eceeb929cc
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
(cherry picked from commit 1b6633d1ce86eaf43b750a03a785793512e487ed)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

4 files changed, 39 insertions, 9 deletions

diff --git a/src/core/net/system_network_context_manager.cpp b/src/core/net/system_network_context_manager.cpp
index 962266d78..f6e7cb630 100644
--- a/src/core/net/system_network_context_manager.cpp
+++ b/src/core/net/system_network_context_manager.cpp
@@ -292,7 +292,15 @@ void SystemNetworkContextManager::ConfigureDefaultNetworkContextParams(network::
     // respect prefs::kEnableReferrers from the appropriate pref store.
     network_context_params->enable_referrers = false;
 
-    network_context_params->proxy_resolver_factory = ChromeMojoProxyResolverFactory::CreateWithSelfOwnedReceiver();
+    const base::CommandLine& command_line =
+      *base::CommandLine::ForCurrentProcess();
+
+    if (command_line.HasSwitch(switches::kSingleProcess)) {
+      LOG(ERROR) << "Cannot use V8 Proxy resolver in single process mode.";
+    } else {
+      network_context_params->proxy_resolver_factory =
+          ChromeMojoProxyResolverFactory::CreateWithSelfOwnedReceiver();
+    }
 
     // Use the SystemNetworkContextManager to populate and update SSL
     // configuration. The SystemNetworkContextManager is owned by the
diff --git a/tests/auto/widgets/proxypac/CMakeLists.txt b/tests/auto/widgets/proxypac/CMakeLists.txt
index 1dd2c8bec..d3ddfd0c5 100644
--- a/tests/auto/widgets/proxypac/CMakeLists.txt
+++ b/tests/auto/widgets/proxypac/CMakeLists.txt
@@ -21,6 +21,22 @@ set_tests_properties(tst_proxypac_file PROPERTIES
     ENVIRONMENT QTWEBENGINE_CHROMIUM_FLAGS=${fileEnvArg}
 )
 
+if(NOT (LINUX AND CMAKE_CROSSCOMPILING))
+    set(fileEnvArg "--single-process ${fileEnvArg}")
+
+    qt_internal_add_test(tst_proxypac_single_process
+        SOURCES
+            tst_proxypac.cpp
+        LIBRARIES
+            Qt::WebEngineCore
+            Test::HttpServer
+    )
+
+    set_tests_properties(tst_proxypac_single_process PROPERTIES
+        ENVIRONMENT QTWEBENGINE_CHROMIUM_FLAGS=${fileEnvArg}
+    )
+endif()
+
 qt_internal_add_test(tst_proxypac_qrc
     SOURCES
         tst_proxypac.cpp
@@ -40,8 +56,6 @@ set_tests_properties(tst_proxypac_qrc PROPERTIES
 )
 
 qt_internal_add_resource(tst_proxypac_qrc "proxypac"
-    PREFIX
-        "/"
-    FILES
-        "proxy.pac"
+    PREFIX "/"
+    FILES "proxy.pac"
 )
diff --git a/tests/auto/widgets/proxypac/proxy.pac b/tests/auto/widgets/proxypac/proxy.pac
index 1d29847b9..966c37ba5 100644
--- a/tests/auto/widgets/proxypac/proxy.pac
+++ b/tests/auto/widgets/proxypac/proxy.pac
@@ -2,6 +2,6 @@ function FindProxyForURL(url, host)
 {
    if (shExpMatch(host, "*.proxy1.com")) return "PROXY localhost:5551";
    if (shExpMatch(host, "*.proxy2.com")) return "PROXY localhost:5552";
-   return "PROXY proxy.url:8080";
+   return "DIRECT";
 }
 
diff --git a/tests/auto/widgets/proxypac/tst_proxypac.cpp b/tests/auto/widgets/proxypac/tst_proxypac.cpp
index 223c995e0..0b218aef9 100644
--- a/tests/auto/widgets/proxypac/tst_proxypac.cpp
+++ b/tests/auto/widgets/proxypac/tst_proxypac.cpp
@@ -33,7 +33,6 @@
 #include <QWebEnginePage>
 #include <QNetworkProxy>
 
-
 class tst_ProxyPac : public QObject {
     Q_OBJECT
 public:
@@ -64,11 +63,20 @@ void tst_ProxyPac::proxypac()
 
     QWebEngineProfile profile;
     QWebEnginePage page(&profile);
+
+    const bool v8_proxy_resolver_enabled = !fromEnv.contains("--single-process");
     page.load(QUrl("http://test.proxy1.com"));
-    QTRY_COMPARE(proxySpy1.count() >= 1, true);
+    QTRY_COMPARE(proxySpy1.count() >= 1, v8_proxy_resolver_enabled);
     QVERIFY(proxySpy2.count() == 0);
     page.load(QUrl("http://test.proxy2.com"));
-    QTRY_COMPARE(proxySpy2.count() >= 1 , true);
+    QTRY_COMPARE(proxySpy2.count() >= 1, v8_proxy_resolver_enabled);
+
+    // check for crash
+    QSignalSpy spyFinished(&page, &QWebEnginePage::loadFinished);
+    page.load(QUrl("https://contribute.qt-project.org"));
+
+    QTRY_VERIFY_WITH_TIMEOUT(!spyFinished.isEmpty(), 100000);
+
 }
 
 #include "tst_proxypac.moc"