Language service hangs after custom provider times out

[HampusAdolfsson]

Environment

• OS and Version: Windows 11 version 10.0.22631
• VS Code Version: 1.103.1
• C/C++ Extension Version: 1.26.3

Bug Summary and Steps to Reproduce

Bug Summary: When using a custom configuration provider for intellisense and the provider hits the two second timeout for providing a configuration for a file, the C/C++ language service sometimes hangs. In this state, it doesn't respond to LSP requests (e.g. hovering a symbol shows "Loading..." forever), running C/C++: Log Diagnostics does nothing and the Language Status popup shows as parsing indefinitely:

Steps to reproduce:

I can reproduce the issue with this sample configuration provider:

import { dirname } from 'path';
import * as vscode from 'vscode';
import { CppToolsApi, Version, CustomConfigurationProvider, getCppToolsApi, SourceFileConfigurationItem, WorkspaceBrowseConfiguration } from 'vscode-cpptools';

let api: CppToolsApi | undefined = undefined;

export async function activate(context: vscode.ExtensionContext) {
	api = await getCppToolsApi(Version.v2);
	const provider = new Provider();
	if (api) {
		if (api.notifyReady) {
			api.registerCustomConfigurationProvider(provider);
			api.notifyReady(provider);
		}
	}
}
export function deactivate() {
	api?.dispose();
}

class Provider implements CustomConfigurationProvider {
	name: string = "cpptools-provider";
	extensionId: string = "cpptools-provider";

	canProvideConfiguration(uri: vscode.Uri, token?: vscode.CancellationToken): Thenable<boolean> {
		return Promise.resolve(true);
	}
	async provideConfigurations(uris: vscode.Uri[], token?: vscode.CancellationToken): Promise<SourceFileConfigurationItem[]> {
		console.log(`cpptools-provider: provideConfigurations called for ${uris.length} URIs.`);
		await new Promise(resolve => setTimeout(resolve, 5000)); // Simulate async work
		return uris.map(uri => {
			return {
				uri,
				configuration: {
					defines: [],
					includePath: [dirname(uri.fsPath)],
					compilerPath: "",
					standard: "c17",
					compilerArgs: [],
					intelliSenseMode: "windows-clang-arm",
				}
			};
		});
	}
	canProvideBrowseConfiguration(token?: vscode.CancellationToken): Thenable<boolean> {
		return Promise.resolve(true);
	}
	provideBrowseConfiguration(token?: vscode.CancellationToken): Thenable<WorkspaceBrowseConfiguration | null> {
		return Promise.resolve(null);
	}
	canProvideBrowseConfigurationsPerFolder(token?: vscode.CancellationToken): Thenable<boolean> {
		return Promise.resolve(false);
	}
	provideFolderBrowseConfiguration(uri: vscode.Uri, token?: vscode.CancellationToken): Thenable<WorkspaceBrowseConfiguration | null> {
		throw new Error('Method not implemented.');
	}
	dispose() {
	}
}

Steps:

1. Run the code above as an extension (with "*" as the activation event)
2. Open a folder with a C/C++ codebase that is large enough that it takes more than ~6 seconds to index
3. Open a C/C++ file to trigger the configuration provider
4. Wait until the indexing would normally be finished. As far as I can tell, if running C/C++: Log Diagnostics produces any output, the language service is still indexing; if it does not, the language service has hanged.

For me, this takes a few tries to hit. It only hangs about once every four tries.

Configuration and Logs

loggingLevel: 6
Custom configuration provider 'cpptools-provider' registered
LSP: (received - deferred) textDocument/didOpen: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c
LSP: (received) cpptools/initialize (id: 1)
LSP: (invoked) cpptools/initialize (id: 1)
cpptools version (TypeScript): 1.26.3
cpptools version (native): 1.26.3.0
Autocomplete is enabled.
Error squiggles are enabled if all header dependencies are resolved.
Hover is enabled.
IntelliSense Engine = default.
LSP: Sending response (id: 1)
LSP: (received) cpptools/queryCompilerDefaults (id: 2)
LSP: (invoked) cpptools/queryCompilerDefaults (id: 2)
Compiler info database not connected - skipping load.
Compiler info database not connected - skipping load.
LSP: Sending response (id: 2)
LSP: (received) cpptools/queryCompilerDefaults (id: 3)
LSP: (invoked) cpptools/queryCompilerDefaults (id: 3)
Compiler info database not connected - skipping load.
Compiler info database not connected - skipping load.
LSP: Sending response (id: 3)
LSP: (received) cpptools/didChangeCppProperties (id: 4)
LSP: (invoked) cpptools/didChangeCppProperties (id: 4)
Code browsing service initialized
LSP: (received - deferred) cpptools/didChangeVisibleTextEditors
Populating file name cache...
LSP: (received) cpptools/didChangeSettings
Attempting to get defaults from C compiler in "compilerPath" property: 'cl.exe'
Attempting to get defaults from C++ compiler in "compilerPath" property: 'cl.exe'
  Folder: C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\CPPWINRT will be indexed
  Folder: C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\SHARED will be indexed
  Folder: C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\UCRT will be indexed
  Folder: C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\UM will be indexed
  Folder: C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\WINRT will be indexed
  Folder: C:\PROGRAM FILES\MICROSOFT VISUAL STUDIO\2022\PROFESSIONAL\VC\TOOLS\MSVC\14.40.33807\ATLMFC\INCLUDE will be indexed
  Folder: C:\PROGRAM FILES\MICROSOFT VISUAL STUDIO\2022\PROFESSIONAL\VC\TOOLS\MSVC\14.40.33807\INCLUDE will be indexed
  Folder: D:\EW PROJECTS\ARM\9.50.1\ST\STM32F0XX\IAR-STM32F051R8-SK\UART-LCD will be indexed
LSP: (queued) textDocument/didOpen: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c
LSP: (queued) cpptools/didChangeVisibleTextEditors
LSP: Sending response (id: 4)
LSP: (invoked) cpptools/didChangeSettings
Discovering files...
Autocomplete is enabled.
Error squiggles are enabled if all header dependencies are resolved.
Hover is enabled.
IntelliSense Engine = default.
Enhanced Colorization is enabled.
LSP: (invoked) textDocument/didOpen: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c
LSP: (invoked) cpptools/didChangeVisibleTextEditors
Intellisense update pending for: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c
Requesting a custom configuration for: D:\EW PROJECTS\ARM\9.50.1\ST\STM32F0XX\IAR-STM32F051R8-SK\UART-LCD\MAIN.C
  Processing folder (recursive): C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\UCRT
  Processing folder (recursive): C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\CPPWINRT
  Processing folder (recursive): C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\SHARED
  Processing folder (recursive): C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\UM
LSP: (received) cpptools/didChangeCppProperties (id: 5)
LSP: (invoked) cpptools/didChangeCppProperties (id: 5)
Attempting to get defaults from C compiler in "compilerPath" property: 'cl.exe'
LSP: (received) cpptools/didChangeVisibleTextEditors
Attempting to get defaults from C++ compiler in "compilerPath" property: 'cl.exe'
  Folder: C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\CPPWINRT will be indexed
  Folder: C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\SHARED will be indexed
  Folder: C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\UCRT will be indexed
  Folder: C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\UM will be indexed
  Folder: C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\WINRT will be indexed
  Folder: C:\PROGRAM FILES\MICROSOFT VISUAL STUDIO\2022\PROFESSIONAL\VC\TOOLS\MSVC\14.40.33807\ATLMFC\INCLUDE will be indexed
  Folder: C:\PROGRAM FILES\MICROSOFT VISUAL STUDIO\2022\PROFESSIONAL\VC\TOOLS\MSVC\14.40.33807\INCLUDE will be indexed
  Folder: D:\EW PROJECTS\ARM\9.50.1\ST\STM32F0XX\IAR-STM32F051R8-SK\UART-LCD will be indexed
LSP: Sending response (id: 5)
LSP: (invoked) cpptools/didChangeVisibleTextEditors
  Processing folder (recursive): C:\PROGRAM FILES (X86)\WINDOWS KITS\10\INCLUDE\10.0.22621.0\WINRT
LSP: (received) cpptools/didChangeVisibleTextEditors
LSP: (invoked) cpptools/didChangeVisibleTextEditors
LSP: (received) cpptools/getDocumentSymbols: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 6)
LSP: (invoked) cpptools/getDocumentSymbols: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 6)
LSP: Sending response (id: 6)
  Processing folder (non-recursive): C:\PROGRAM FILES\MICROSOFT VISUAL STUDIO\2022\PROFESSIONAL\VC\TOOLS\MSVC\14.40.33807\ATLMFC\INCLUDE
LSP: (received) cpptools/getCodeActions: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 7)
LSP: (invoked) cpptools/getCodeActions: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 7)
LSP: Sending response (id: 7)
LSP: (received) cpptools/getFoldingRanges: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 8)
LSP: (invoked) cpptools/getFoldingRanges: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 8)
LSP: Sending response (id: 8)
LSP: (received) cpptools/pauseParsing
LSP: (invoked) cpptools/pauseParsing
LSP: (received) cpptools/clearCustomConfigurations
LSP: (invoked) cpptools/clearCustomConfigurations
LSP: (received) cpptools/getCodeActions: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 9)
LSP: (invoked) cpptools/getCodeActions: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 9)
LSP: Sending response (id: 9)
LSP: $/cancelRequest (<unknown/completed>, id: 7)
LSP: (received) cpptools/clearCustomConfigurations
LSP: (invoked) cpptools/clearCustomConfigurations
  Processing folder (non-recursive): C:\PROGRAM FILES\MICROSOFT VISUAL STUDIO\2022\PROFESSIONAL\VC\TOOLS\MSVC\14.40.33807\INCLUDE
  Processing folder (recursive): D:\EW PROJECTS\ARM\9.50.1\ST\STM32F0XX\IAR-STM32F051R8-SK\UART-LCD
Done populating filename cache. Elapsed time: 159 ms
  Discovering files: 5926 file(s) processed
  0 file(s) removed from database
Done discovering files.
Parsing remaining files...
  Parsing: 0 files(s) processed
Done parsing remaining files.
IntelliSense update scheduled and TU acquisition started for: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c
Requesting a custom configuration for: D:\EW PROJECTS\ARM\9.50.1\ST\STM32F0XX\IAR-STM32F051R8-SK\UART-LCD\MAIN.C
LSP: (received) cpptools/getCodeActions: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 10)
LSP: $/cancelRequest (cpptools/getCodeActions, id: 10)
LSP: (received) cpptools/getCodeActions: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 11)
LSP: $/cancelRequest (cpptools/getCodeActions, id: 11)
LSP: (received) cpptools/getCodeActions: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 12)
LSP: (received) cpptools/resumeParsing
LSP: (received) cpptools/finishedRequestCustomConfig: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c
LSP: (invoked) cpptools/finishedRequestCustomConfig: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c
LSP: (received) cpptools/didChangeTextEditorSelection
LSP: $/cancelRequest (cpptools/getCodeActions, id: 12)
LSP: (received) cpptools/hover: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 13)
LSP: $/cancelRequest (cpptools/hover, id: 13)
LSP: (received) cpptools/hover: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 14)
LSP: $/cancelRequest (cpptools/hover, id: 14)
LSP: (received) cpptools/hover: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 15)
LSP: $/cancelRequest (cpptools/hover, id: 15)
LSP: (received) cpptools/hover: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 16)
LSP: $/cancelRequest (cpptools/hover, id: 16)
LSP: (received) cpptools/hover: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 17)
LSP: (received) cpptools/didChangeTextEditorSelection
LSP: (received) cpptools/getCodeActions: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 18)
LSP: $/cancelRequest (cpptools/hover, id: 17)
LSP: (received) cpptools/hover: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 19)
LSP: $/cancelRequest (cpptools/hover, id: 19)
LSP: (received) cpptools/didChangeTextEditorSelection
LSP: (received) cpptools/didChangeTextEditorSelection
LSP: (received) cpptools/getCodeActions: file:///d%3A/EW%20Projects/arm/9.50.1/ST/STM32F0xx/IAR-STM32F051R8-SK/UART-LCD/main.c (id: 20)
LSP: $/cancelRequest (cpptools/getCodeActions, id: 18)

Other Extensions

No response

Additional context

No response

[sean-mcmanus]

@HampusAdolfsson I'm not able to repro the issue. If there's a timeout, it falls back to configuration using the base configuration -- do you repro the same issue if you remove the configurationProvider so that it always uses them base c_cpp_properties.json configuration? Otherwise, can you attach a debugger to the cpptools.exe process (https://github.com/microsoft/vscode-cpptools/wiki/Attaching-debugger-to-cpptools-or-cpptools%E2%80%90srv ) and look for call stacks that appear to be doing work and or doing work but our stuck (i.e. ignoring the small threads that are just idle). Also, if you set the C_Cpp.loggingLevel to the hidden value of "8" temporarily it might show more logging.

[HampusAdolfsson]

@sean-mcmanus I see, it's unfortunate that it doesn't work on your end. The repro seems very timing-sensitive, but I've successfully run it on two machines so I don't think it's some machine-specific thing.

do you repro the same issue if you remove the configurationProvider so that it always uses them base c_cpp_properties.json configuration?

No, the base configuration works as expected.

Here are the threads doing work:

------populate completion cache thread------
ntdll.dll!NtWaitForAlertByThreadId() (Unknown Source:0)
ntdll.dll!RtlAcquireSRWLockExclusive() (Unknown Source:0)
msvcp140.dll!mtx_do_lock(_Mtx_internal_imp_t * mtx, const _timespec64 * target) Line 96 (d:\a\_work\1\s\src\vctools\crt\github\stl\src\mutex.cpp:96)
cpptools.exe!std::unique_lock<class std::recursive_mutex>::unique_lock<class std::recursive_mutex>(class std::recursive_mutex &) (Unknown Source:0)
cpptools.exe!intellisense_client_manager::get_compilation_args(class msvc::canonicalized_file_path_t const &,struct get_compilation_args_options const &,class msvc::canonicalized_file_path_t *) (Unknown Source:0)
cpptools.exe!include_auto_complete::cache::populate(class msvc::canonicalized_file_path_t const &) (Unknown Source:0)
cpptools.exe!std::_Func_impl_no_alloc<`cpptools_context::cpptools_context'::`1'::<lambda_14_>,void,msvc::canonicalized_file_path_t &&>::_Do_call() (Unknown Source:0)
cpptools.exe!`msvc::deque_thread<class msvc::canonicalized_file_path_t>::defer(class msvc::canonicalized_file_path_t &&)'::`2'::<lambda_1>::operator()(void) (Unknown Source:0)
cpptools.exe!msvc::thread_manager_t::do_work(unsigned int) (Unknown Source:0)
cpptools.exe!msvc::thread_helper_t::thread_entry(void *) (Unknown Source:0)
ucrtbase.dll!thread_start<unsigned int (__cdecl*)(void *),1>() (Unknown Source:0)
kernel32.dll!BaseThreadInitThunk() (Unknown Source:0)
ntdll.dll!RtlUserThreadStart() (Unknown Source:0)

------lsp_manager thread------
ntdll.dll!NtWaitForAlertByThreadId() (Unknown Source:0)
ntdll.dll!RtlAcquireSRWLockExclusive() (Unknown Source:0)
msvcp140.dll!mtx_do_lock(_Mtx_internal_imp_t * mtx, const _timespec64 * target) Line 96 (d:\a\_work\1\s\src\vctools\crt\github\stl\src\mutex.cpp:96)
cpptools.exe!std::unique_lock<class std::recursive_mutex>::unique_lock<class std::recursive_mutex>(class std::recursive_mutex &) (Unknown Source:0)
cpptools.exe!intellisense_client_manager::purge_old_clients(class std::chrono::duration<__int64,struct std::ratio<1,1> > const &,bool,bool) (Unknown Source:0)
cpptools.exe!cpptools_context::cpptools_onIntervalTimer(void) (Unknown Source:0)
cpptools.exe!``cpptools_context::initialize'::`74'::<lambda_4>::operator()'::`2'::<lambda_1>::operator()() (Unknown Source:0)
cpptools.exe!`lsp_manager::deploy_task'::`2'::<lambda_1>::operator()() (Unknown Source:0)
cpptools.exe!msvc::thread_manager_t::do_work(unsigned int) (Unknown Source:0)
cpptools.exe!msvc::thread_helper_t::thread_entry(void *) (Unknown Source:0)
ucrtbase.dll!thread_start<unsigned int (__cdecl*)(void *),1>() (Unknown Source:0)
kernel32.dll!BaseThreadInitThunk() (Unknown Source:0)
ntdll.dll!RtlUserThreadStart() (Unknown Source:0)

------parse_root thread------
ntdll.dll!NtWaitForAlertByThreadId() (Unknown Source:0)
ntdll.dll!RtlAcquireSRWLockExclusive() (Unknown Source:0)
msvcp140.dll!mtx_do_lock(_Mtx_internal_imp_t * mtx, const _timespec64 * target) Line 96 (d:\a\_work\1\s\src\vctools\crt\github\stl\src\mutex.cpp:96)
cpptools.exe!std::unique_lock<class std::recursive_mutex>::unique_lock<class std::recursive_mutex>(class std::recursive_mutex &) (Unknown Source:0)
cpptools.exe!intellisense_client_manager::remove_header_clients(void) (Unknown Source:0)
cpptools.exe!cpptools_context::parse_root(bool) (Unknown Source:0)
cpptools.exe!std::_Func_impl_no_alloc<`cpptools_context::cpptools_context'::`1'::<lambda_11_>,void,cpptools_context::browse_engine_update_action_and_task_token &&>::_Do_call() (Unknown Source:0)
cpptools.exe!`msvc::deque_thread<struct cpptools_context::browse_engine_update_action_and_task_token>::defer(struct cpptools_context::browse_engine_update_action_and_task_token &&)'::`2'::<lambda_1>::operator()(void) (Unknown Source:0)
cpptools.exe!msvc::thread_manager_t::do_work(unsigned int) (Unknown Source:0)
cpptools.exe!msvc::thread_helper_t::thread_entry(void *) (Unknown Source:0)
ucrtbase.dll!thread_start<unsigned int (__cdecl*)(void *),1>() (Unknown Source:0)
kernel32.dll!BaseThreadInitThunk() (Unknown Source:0)
ntdll.dll!RtlUserThreadStart() (Unknown Source:0)

------VC++ Worker Thread: 10------
ntdll.dll!NtWaitForAlertByThreadId() (Unknown Source:0)
ntdll.dll!RtlSleepConditionVariableSRW() (Unknown Source:0)
KernelBase.dll!SleepConditionVariableSRW() (Unknown Source:0)
cpptools.exe!_Cnd_timedwait_for_impl() (Unknown Source:0)
cpptools.exe!std::condition_variable_any::wait_for<class std::unique_lock<struct msvc::mutex_t>,__int64,struct std::ratio<1,1000000000> >(class std::unique_lock<struct msvc::mutex_t> &,class std::chrono::duration<__int64,struct std::ratio<1,1000000000> > const &) (Unknown Source:0)
cpptools.exe!cpptools_context::request_custom_configuration(class msvc::canonicalized_file_path_t const &,bool &,class std::function<bool (void)> const &) (Unknown Source:0)
cpptools.exe!``intellisense_client_manager::acquire_intellisense_client'::`2'::<lambda_2>::operator()'::`4'::<lambda_2>::operator()() (Unknown Source:0)
cpptools.exe!`intellisense_client_manager::acquire_intellisense_client'::`2'::<lambda_2>::operator()() (Unknown Source:0)
cpptools.exe!msvc::thread_manager_t::do_work(unsigned int) (Unknown Source:0)
cpptools.exe!msvc::thread_helper_t::thread_entry(void *) (Unknown Source:0)
ucrtbase.dll!thread_start<unsigned int (__cdecl*)(void *),1>() (Unknown Source:0)
kernel32.dll!BaseThreadInitThunk() (Unknown Source:0)
ntdll.dll!RtlUserThreadStart() (Unknown Source:0)

The first three threads are all waiting for the same lock, which is being held by the worker thread. The worker thread seems to be waiting indefinitely for a custom configuration even though the provider has timed out.

I also noticed that cpptools requests a custom configuration for the same file several times before it hangs, and I see multiple timeout popups in quick succession (with less than two seconds in-between):

20250822-0729-53.5764618.mp4

Here are the logs with logging level 8:
https://gist.github.com/HampusAdolfsson/d0456f1698277b7d33b2c3b498ed20b2

[Colengms]

Hi @HampusAdolfsson .

Those stacks look to be expected. They don't appear to show a deadlock. They show that the native component is still waiting to receive a FinishedRequestCustomConfig message from the TypeScript side, which is expected even on failure. That message is sent by a 'finally', and at a higher priority than other messages, so is always expected. Can you provide all other threads, in case there might be something else blocking our message queue? Otherwise, it seems like we should be looking at the TypeScript side to figure out why that 'finished' message is not being sent.

The log you provided consists mostly of database population. Would it be possible to regenerate one, after database population is complete? Also, could you check the Console output (under Help -> Toggle Developer Tools), as that might show evidence of an exception being thrown in the TypeScript component.

[HampusAdolfsson]

@Colengms

Here are the other stacks:

------Main Thread------
ntdll.dll!NtReadFile() (Unknown Source:0)
KernelBase.dll!ReadFile() (Unknown Source:0)
ucrtbase.dll!_read_nolock() (Unknown Source:0)
ucrtbase.dll!_read() (Unknown Source:0)
ucrtbase.dll!common_refill_and_read_nolock<char>() (Unknown Source:0)
ucrtbase.dll!fgetc() (Unknown Source:0)
[Inline Frame] msvcp140.dll!std::_Fgetc(char &) Line 75 (d:\a\_work\1\s\src\vctools\crt\github\stl\inc\__msvc_filebuf.hpp:75)
msvcp140.dll!std::basic_filebuf<char,std::char_traits<char>>::uflow() Line 490 (d:\a\_work\1\s\src\vctools\crt\github\stl\inc\__msvc_filebuf.hpp:490)
msvcp140.dll!std::basic_filebuf<char,std::char_traits<char>>::underflow() Line 470 (d:\a\_work\1\s\src\vctools\crt\github\stl\inc\__msvc_filebuf.hpp:470)
cpptools.exe!std::getline<char,struct std::char_traits<char>,class std::allocator<char> >(class std::basic_istream<char,struct std::char_traits<char> > &&,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > &,char) (Unknown Source:0)
cpptools.exe!lsp_manager::read_message(class lsp_manager::client_message &) (Unknown Source:0)
cpptools.exe!lsp_manager::process_messages(class std::function<void (void)> const &,class std::function<void (int)> const &,class std::function<void (struct lsp_client_info const &&)> const &) (Unknown Source:0)
cpptools.exe!main() (Unknown Source:0)
cpptools.exe!__scrt_common_main_seh() (Unknown Source:0)
kernel32.dll!BaseThreadInitThunk() (Unknown Source:0)
ntdll.dll!RtlUserThreadStart() (Unknown Source:0)

------msvc::channel_manager::_loop_thread------
ntdll.dll!NtRemoveIoCompletionEx() (Unknown Source:0)
KernelBase.dll!GetQueuedCompletionStatusEx() (Unknown Source:0)
cpptools.exe!uv__poll() (Unknown Source:0)
cpptools.exe!uv_run() (Unknown Source:0)
cpptools.exe!msvc::thread_proc() (Unknown Source:0)
cpptools.exe!msvc::thread_t::invoker_t<void (*)(class std::shared_ptr<class msvc::loop_t>),class std::shared_ptr<class msvc::loop_t> &>::invoke(void) (Unknown Source:0)
cpptools.exe!msvc::thread_helper_t::thread_entry(void *) (Unknown Source:0)
ucrtbase.dll!thread_start<unsigned int (__cdecl*)(void *),1>() (Unknown Source:0)
kernel32.dll!BaseThreadInitThunk() (Unknown Source:0)
ntdll.dll!RtlUserThreadStart() (Unknown Source:0)

------mscv::timer_queue_t::_thread--ntdll.dll!NtWaitForAlertByThreadId() (Unknown Source:0)
ntdll.dll!RtlSleepConditionVariableSRW() (Unknown Source:0)
KernelBase.dll!SleepConditionVariableSRW() (Unknown Source:0)
cpptools.exe!_Cnd_timedwait_for_impl() (Unknown Source:0)
cpptools.exe!std::condition_variable_any::wait_for<class std::unique_lock<struct msvc::mutex_t>,__int64,struct std::ratio<1,1000000000> >(class std::unique_lock<struct msvc::mutex_t> &,class std::chrono::duration<__int64,struct std::ratio<1,1000000000> > const &) (Unknown Source:0)
cpptools.exe!`msvc::timer_queue_t::timer_queue_t'::`2'::<lambda_1>::operator()() (Unknown Source:0)
cpptools.exe!msvc::thread_helper_t::thread_entry(void *) (Unknown Source:0)
ucrtbase.dll!thread_start<unsigned int (__cdecl*)(void *),1>() (Unknown Source:0)
kernel32.dll!BaseThreadInitThunk() (Unknown Source:0)
ntdll.dll!RtlUserThreadStart() (Unknown Source:0)----

------antrl_parse_routine------
ntdll.dll!NtWaitForAlertByThreadId() (Unknown Source:0)
ntdll.dll!RtlSleepConditionVariableSRW() (Unknown Source:0)
KernelBase.dll!SleepConditionVariableSRW() (Unknown Source:0)
[Inline Frame] msvcp140.dll!_Primitive_wait_for(_Cnd_internal_imp_t * const) Line 14 (d:\a\_work\1\s\src\vctools\crt\github\stl\src\primitives.hpp:14)
[Inline Frame] msvcp140.dll!_Primitive_wait(_Cnd_internal_imp_t * const) Line 18 (d:\a\_work\1\s\src\vctools\crt\github\stl\src\primitives.hpp:18)
msvcp140.dll!_Cnd_wait(_Cnd_internal_imp_t * cond, _Mtx_internal_imp_t * mtx) Line 58 (d:\a\_work\1\s\src\vctools\crt\github\stl\src\cond.cpp:58)
cpptools.exe!run_tag_parser(void) (Unknown Source:0)
cpptools.exe!before_tu_wrapup(void) (Unknown Source:0)
cpptools.exe!process_translation_unit(char const *,int,struct an_exported_template_file *) (Unknown Source:0)
cpptools.exe!cfe_main(int,char * * const) (Unknown Source:0)
cpptools.exe!cfe_main_exception_handler(int,char * * const) (Unknown Source:0)
cpptools.exe!antlr_parse_routine() (Unknown Source:0)
cpptools.exe!msvc::thread_helper_t::thread_entry(void *) (Unknown Source:0)
ucrtbase.dll!thread_start<unsigned int (__cdecl*)(void *),1>() (Unknown Source:0)
kernel32.dll!BaseThreadInitThunk() (Unknown Source:0)
ntdll.dll!RtlUserThreadStart() (Unknown Source:0)

------VC++ Thread Pool Balancer------
ntdll.dll!NtWaitForAlertByThreadId() (Unknown Source:0)
ntdll.dll!RtlSleepConditionVariableSRW() (Unknown Source:0)
KernelBase.dll!SleepConditionVariableSRW() (Unknown Source:0)
cpptools.exe!_Cnd_timedwait_for_impl() (Unknown Source:0)
cpptools.exe!`msvc::thread_manager_t::internal_initialize'::`2'::<lambda_1>::operator()() (Unknown Source:0)
cpptools.exe!msvc::thread_helper_t::thread_entry(void *) (Unknown Source:0)
ucrtbase.dll!thread_start<unsigned int (__cdecl*)(void *),1>() (Unknown Source:0)
kernel32.dll!BaseThreadInitThunk() (Unknown Source:0)
ntdll.dll!RtlUserThreadStart() (Unknown Source:0)

------VC++ Worker Threads (all except number 10)------
ntdll.dll!NtWaitForAlertByThreadId() (Unknown Source:0)
ntdll.dll!RtlSleepConditionVariableSRW() (Unknown Source:0)
KernelBase.dll!SleepConditionVariableSRW() (Unknown Source:0)
[Inline Frame] msvcp140.dll!_Primitive_wait_for(_Cnd_internal_imp_t * const) Line 14 (d:\a\_work\1\s\src\vctools\crt\github\stl\src\primitives.hpp:14)
[Inline Frame] msvcp140.dll!_Primitive_wait(_Cnd_internal_imp_t * const) Line 18 (d:\a\_work\1\s\src\vctools\crt\github\stl\src\primitives.hpp:18)
msvcp140.dll!_Cnd_wait(_Cnd_internal_imp_t * cond, _Mtx_internal_imp_t * mtx) Line 58 (d:\a\_work\1\s\src\vctools\crt\github\stl\src\cond.cpp:58)
cpptools.exe!msvc::thread_manager_t::do_work(unsigned int) (Unknown Source:0)
cpptools.exe!msvc::thread_helper_t::thread_entry(void *) (Unknown Source:0)
ucrtbase.dll!thread_start<unsigned int (__cdecl*)(void *),1>() (Unknown Source:0)
kernel32.dll!BaseThreadInitThunk() (Unknown Source:0)
ntdll.dll!RtlUserThreadStart() (Unknown Source:0)


------ntdll.dll!TppWorkerThread() (3 identical threads)------
ntdll.dll!NtWaitForWorkViaWorkerFactory() (Unknown Source:0)
ntdll.dll!TppWorkerThread() (Unknown Source:0)
kernel32.dll!BaseThreadInitThunk() (Unknown Source:0)
ntdll.dll!RtlUserThreadStart() (Unknown Source:0)

The log you provided consists mostly of database population. Would it be possible to regenerate one, after database population is complete?

Let me know if I misunderstood you, but I've generated new logs where I:

1. Open VS Code with no C files open
2. Wait until the logs settle
3. Clear the logs
4. Open a .c file to trigger cpptools to update intellisense

Here's a run where I observed the deadlock:

https://gist.github.com/HampusAdolfsson/082a724e27e2f2006bab666626b78261

For reference, here's a run where I did not observe it, i.e., intellisense finished configuring correctly:

https://gist.github.com/HampusAdolfsson/8945d13d9079ae2c8e0a764468ef7b48

They look very similar to me. However, you can see that cpptools requests a custom configuration twice and in the failed run it only receives one cpptools/finishedRequestCustomConfig.

Also, could you check the Console output (under Help -> Toggle Developer Tools), as that might show evidence of an exception being thrown in the TypeScript component.

Nothing out of the ordinary here as far as I can tell:

log.ts:440  INFO Started local extension host with pid 43096.
log.ts:440  INFO Loading development extension at d:\repos\VSCode\cpptools-config-provider\cpptools-provider
languagesAssociations.ts:73 Overwriting extension <<copilot-instructions.md>> to now point to mime <<text/x-instructions>>
(anonymous) @ languagesAssociations.ts:73
localProcessExtensionHost.ts:280 Extension Host
localProcessExtensionHost.ts:281 Debugger attached.
log.ts:440  INFO Settings Sync: Account status changed from uninitialized to available
log.ts:460   ERR [Extension Host] (node:43096) [DEP0040] DeprecationWarning: The `punycode` module is deprecated. Please use a userland alternative instead.
(Use `Code --trace-deprecation ...` to show where the warning was created)
error @ log.ts:460
console.ts:137 [Extension Host] (node:43096) [DEP0040] DeprecationWarning: The `punycode` module is deprecated. Please use a userland alternative instead.
(Use `Code --trace-deprecation ...` to show where the warning was created) (at file:///c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:198:31117)
Ims @ console.ts:137
console.ts:137 [Extension Host] Failed to register the Copilot Context Provider. (at console.<anonymous> (file:///c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:198:31117))
log.ts:440  INFO Auto updating outdated extensions. github.copilot, github.copilot-chat
log.ts:440  INFO [perf] Render performance baseline is 13ms
console.ts:137 [Extension Host] Configuration Provider timed out in 2000ms. (at console.<anonymous> (file:///c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:198:31117))
Ims @ console.ts:137
log.ts:460   ERR Conflict in settings file : Ignoring terminal.integrated.fontLigatures.enabled as terminal.integrated.fontLigatures is true
error @ log.ts:460
console.ts:137 [Extension Host] cpptools-provider: provideConfigurations called for 1 URIs. (at console.<anonymous> (file:///c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:198:31117))
console.ts:137 [Extension Host] cpptools-provider: provideConfigurations called for 1 URIs. (at console.<anonymous> (file:///c:/Users/hampusad/AppData/Local/Programs/Microsoft%20VS%20Code/resources/app/out/vs/workbench/api/node/extensionHostProcess.js:198:31117))

[sean-mcmanus]

@HampusAdolfsson Can you confirm that there is an info notification popup in the bottom right notification section? Does bypassing the notification fix the issue for you?