Windows: fix spurious crashes in configuration_loader

When event_loop gives the IOCP result to
change_detecting_filesystem_win32, it sometimes gives a bogus error
value. This is because we call GetLastError after calling
GetQueuedCompletionStatus, even if GQCS succeeds. If GQCS succeeds, it
doesn't set LastError, so we end up getting whatever error was set prior
on the thread. Sometimes this is WAIT_TIMEOUT (which we stubbornly
handle), and sometimes this is ERROR_PATH_NOT_FOUND (due to
initialize_global_loggers_if_needed failing internally) (which
causes an assertion failure).

Fix spurious crashes and workarounds by giving
change_detecting_filesystem_win32::handle_event ERROR_SUCCESS if
GetQueuedCompletionStatus succeeds.

Thanks to https://twitch.tv/EmptyGroceryBag for suggesting that I look
at Process Monitor to see where ERROR_PATH_NOT_FOUND was coming from.

Author: strager

docs/CHANGELOG.md

@@ -30,6 +30,8 @@ Beta release.
 * Various crashes on invalid code have been fixed.
 * quick-lint-js consumes less memory for pathlogical code patterns.
 * VS Code: The extension no longer tries to load an ARM64 DLL on Windows x64.
+* VS Code and LSP server: In Windows debug builds, crashes no longer occur
+  supriously when the filesystem changes.
 
 ## 0.5.0 (2021-10-12)
 

src/change-detecting-filesystem-win32.cpp

@@ -130,7 +130,6 @@ bool change_detecting_filesystem_win32::handle_event(
       watched_directory::from_oplock_overlapped(overlapped);
   switch (error) {
   case ERROR_SUCCESS:
-  case WAIT_TIMEOUT:  // FIXME(strager): Why do we sometimes get WAIT_TIMEOUT?
     this->handle_oplock_broke_event(dir, number_of_bytes_transferred);
     return true;
 

test/test-configuration-loader.cpp

@@ -2656,7 +2656,7 @@ void change_detecting_configuration_loader::run_io_thread() {
         /*lpNumberOfBytesTransferred=*/&number_of_bytes_transferred,
         /*lpCompletionKey=*/&completion_key, /*lpOverlapped=*/&overlapped,
         /*dwMilliseconds=*/0);
-    DWORD error = ::GetLastError();
+    DWORD error = ok ? ERROR_SUCCESS : ::GetLastError();
 
     if (!overlapped) {
       switch (error) {