[WPE][GTK] WebProcess crashes at the end of every GLib API test

[obyknovenius]

4b27f17

[WPE][GTK] WebProcess crashes at the end of every GLib API test
https://bugs.webkit.org/show_bug.cgi?id=259303

Reviewed by Michael Catanzaro.

To run web process API tests we need to be able to execute code in
the web process. This is done by using web process extensions.

`WebProcessTest.cpp ` is a base class that implements the initialization
of a web process extension. This class also provides an API for
asserting that the `GObject` objects allocated in the web process during
test execution are deleted at the end of the test.

These `GObject` objects are stored in a static `HashSet`
`s_watchedObjects`. When the web process is terminating
`static void __attribute__((destructor)) checkLeaksAtExit()`
is called to verify that `s_watchedObjects` is empty, meaning
no objects were leaked.

The problem is that static variable destructors are invoking *before*
any `__attribute__((destructor))` functions. So by the time
`checkLeaksAtExit` is called, `s_watchedObjects` is already deallocated,
leading the web process to crash.

Because the web process extension modules we need for some tests are
located in the default directory, there are being loaded with every
API test. So we got the crash even if we don't run a web process test.

The solution to this problem is to wrap the watched objects hash set
into a static class and check for leaks in its destructor, before the
hash set is deallocated.

* Tools/TestWebKitAPI/Tests/WebKitGLib/DOMElementTest.cpp:
(DOMElementTest::testAutoFill):
* Tools/TestWebKitAPI/Tests/WebKitGLib/EditorTest.cpp:
(WebKitWebEditorTest::testSelectionChanged):
* Tools/TestWebKitAPI/Tests/WebKitGLib/FrameTest.cpp:
(WebKitFrameTest::testJavaScriptContext):
(WebKitFrameTest::testJavaScriptValues):
(WebKitFrameTest::testSubframe):
* Tools/TestWebKitAPI/Tests/WebKitGLib/WebProcessTest.cpp:
(runTest):
(webProcessTestRunnerFinalize):
(windowObjectClearedCallback):
(webkit_web_extension_initialize):
(checkLeaks): Deleted.
(WebProcessTest::assertObjectIsDeletedWhenTestFinishes): Deleted.
(checkLeaksAtExit): Deleted.
* Tools/TestWebKitAPI/Tests/WebKitGLib/WebProcessTest.h:
(Watcher::~Watcher):
(Watcher::assertObjectIsDeletedWhenTestFinishes):
(Watcher::checkLeaks):
* Tools/TestWebKitAPI/Tests/WebKitGtk/AutocleanupsTest.cpp:
(AutocleanupsTest::testWebProcessAutocleanups):
* Tools/TestWebKitAPI/Tests/WebKitGtk/DOMClientRectTest.cpp:
(WebKitDOMClientRectTest::testDivBoundingClientRectPosition):
(WebKitDOMClientRectTest::testDivClientRectsPositionAndLength):
* Tools/TestWebKitAPI/Tests/WebKitGtk/DOMNodeFilterTest.cpp:
(WebKitDOMNodeFilterTest::testTreeWalker):
(WebKitDOMNodeFilterTest::testNodeIterator):
* Tools/TestWebKitAPI/Tests/WebKitGtk/DOMNodeTest.cpp:
(WebKitDOMNodeTest::testHierarchyNavigation):
(WebKitDOMNodeTest::testInsertion):
(WebKitDOMNodeTest::testTagNamesNodeList):
(WebKitDOMNodeTest::testTagNamesHTMLCollection):
(WebKitDOMNodeTest::testDOMCache):
* Tools/TestWebKitAPI/Tests/WebKitGtk/DOMXPathNSResolverTest.cpp:
(WebKitDOMXPathNSResolverTest::evaluateFooChildTextAndCheckResult):
(WebKitDOMXPathNSResolverTest::testXPathNSResolverNative):
(WebKitDOMXPathNSResolverTest::testXPathNSResolverCustom):

Canonical link: https://commits.webkit.org/266127@main

d9b6787

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash f3bdc78)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	❌ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[mcatanzaro]

Good solution.

Technically static objects are also destroyed in exit handlers, but I suppose they are destroyed sooner than the exit handler for the library destructor. Destructors of static objects and exit handlers are all pretty dangerous and we see crashes from them regularly, but in this case the benefit of being able to check for leaks is clearly worth the risk.

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 11db54b)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	❌ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	❌ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	❌ 🧪 api-gtk
	✅ 🛠 tv	🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

[obyknovenius]

@mcatanzaro It would be nice to have an API function which is called when a web process extension is being destroyed. Something like:

webkit_web_process_extension_destroy(WebKitWebProcessExtension* extension)

[webkit-early-warning-system]

EWS run on current version of this PR (hash d9b6787)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[mcatanzaro]

It would be nice to have an API function which is called when a web process extension is being destroyed.

Feel free to create a bug report if there's something you really want to do that cannot be done otherwise.

[webkit-commit-queue]

Committed 266127@main (4b27f17): https://commits.webkit.org/266127@main

Reviewed commits have been landed. Closing PR #15904 and removing active labels.