Add exception handling in task_worker_loop to prevent worker thread termination

[Copilot]

Task: Add try-catch block around do_task() in worker.h

• Add necessary include for logging (ds/internal_logger.h)
• Add try-catch block around task->do_task() call
• Use task->get_name() for descriptive logging in catch handlers
• Handle both std::exception and unknown exceptions
• Create test to verify exception handling
• Build and verify the changes work correctly
• Address review feedback: add <exception> include to worker.h
• Fix test synchronization with bounded timeout (1 second max wait)
• Format all changes with clang-format
• Fix clang-tidy errors in worker.cpp:
  • Move current_throw_trace, demangle_symbol, and format_stacktrace to anonymous namespace (misc-use-anonymous-namespace)
  • Use RAII (std::unique_ptr with custom deleters) instead of manual free() (cppcoreguidelines-no-malloc, cppcoreguidelines-owning-memory)
  • Add NOLINTNEXTLINE for unavoidable free() in deleters and multi-level pointer conversion (bugprone-multi-level-implicit-pointer-conversion)
  • Use auto for real_cxa_throw initialization (modernize-use-auto)
  • Construct backtrace_symbols result directly in unique_ptr for safer RAII

Original prompt

Apply the suggestion from this comment, within the task system itself:
#7630 (comment)

Add a try catch block around the call to do_task() in src/tasks/worker.h to prevent exceptions escaping further. Use task->get_name() for descriptive logging.

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[Copilot]

Pull request overview

This PR improves the task system’s robustness by preventing exceptions thrown from BaseTask::do_task() from escaping the worker loop and terminating worker threads, and adds a regression test to ensure subsequent tasks still run after failures.

Changes:

• Add worker-level try/catch around task->do_task() with logging for std::exception and unknown exceptions.
• Add a doctest verifying the worker continues processing after tasks throw.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
src/tasks/worker.h	Adds exception boundary + failure logging around task execution to keep worker threads alive.
src/tasks/test/basic_tasks.cpp	Adds a regression test covering continued execution after exceptions.

[eddyashton]

@copilot apply changes based on the comments in this thread, and format all changes with clang-format.

[Copilot]

@copilot apply changes based on the comments in this thread, and format all changes with clang-format.

Applied all review feedback and formatted with clang-format (23843eb). All 13 tests pass with 265/265 assertions.

[achamayou]

@copilot fix these:

/usr/bin/cmake -E __run_co_compile --tidy="/usr/bin/clang-tidy;--extra-arg-before=--driver-mode=g++" --source=/__w/CCF/CCF/src/tasks/worker.cpp -- /usr/bin/clang++  -I/__w/CCF/CCF/include -I/__w/CCF/CCF/src -isystem /__w/CCF/CCF/3rdparty/exported -isystem /__w/CCF/CCF/3rdparty/internal -g -std=gnu++20 -fPIC -fcolor-diagnostics -ffile-prefix-map=/__w/CCF/CCF=CCF -fno-omit-frame-pointer -Wall -Wextra -Werror -Wundef -Wpedantic -Wno-unused-parameter -Wno-unused-function -Wshadow -MD -MT CMakeFiles/ccf_tasks.dir/src/tasks/worker.cpp.o -MF CMakeFiles/ccf_tasks.dir/src/tasks/worker.cpp.o.d -o CMakeFiles/ccf_tasks.dir/src/tasks/worker.cpp.o -c /__w/CCF/CCF/src/tasks/worker.cpp
/__w/CCF/CCF/src/tasks/worker.cpp:23:34: error: variable 'current_throw_trace' declared 'static', move to anonymous namespace instead [misc-use-anonymous-namespace,-warnings-as-errors]
   23 |   static thread_local ThrowTrace current_throw_trace = {};
      |                                  ^
/__w/CCF/CCF/src/tasks/worker.cpp:25:22: error: function 'demangle_symbol' declared 'static', move to anonymous namespace instead [misc-use-anonymous-namespace,-warnings-as-errors]
   25 |   static std::string demangle_symbol(const char* raw)
      |                      ^
/__w/CCF/CCF/src/tasks/worker.cpp:51:9: error: do not manage memory manually; use RAII [cppcoreguidelines-no-malloc,-warnings-as-errors]
   51 |         free(demangled);
      |         ^~~~~~~~~~~~~~~
/__w/CCF/CCF/src/tasks/worker.cpp:51:9: error: calling legacy resource function without passing a 'gsl::owner<>' [cppcoreguidelines-owning-memory,-warnings-as-errors]
   51 |         free(demangled);
      |         ^~~~~~~~~~~~~~~
/__w/CCF/CCF/src/tasks/worker.cpp:63:22: error: function 'format_stacktrace' declared 'static', move to anonymous namespace instead [misc-use-anonymous-namespace,-warnings-as-errors]
   63 |   static std::string format_stacktrace(void** frames, int num_frames)
      |                      ^
/__w/CCF/CCF/src/tasks/worker.cpp:71:5: error: do not manage memory manually; use RAII [cppcoreguidelines-no-malloc,-warnings-as-errors]
   71 |     free(symbols);
      |     ^~~~~~~~~~~~~
/__w/CCF/CCF/src/tasks/worker.cpp:71:5: error: calling legacy resource function without passing a 'gsl::owner<>' [cppcoreguidelines-owning-memory,-warnings-as-errors]
   71 |     free(symbols);
      |     ^~~~~~~~~~~~~
/__w/CCF/CCF/src/tasks/worker.cpp:71:10: error: multilevel pointer conversion from 'char **' to 'void *', please use explicit cast [bugprone-multi-level-implicit-pointer-conversion,-warnings-as-errors]
   71 |     free(symbols);
      |          ^
/__w/CCF/CCF/src/tasks/worker.cpp:113:12: error: use auto when initializing with a cast to avoid duplicating the type name [modernize-use-auto,-warnings-as-errors]
  113 |     static CxaThrowFn real_cxa_throw =
      |            ^~~~~~~~~~
      |            auto

[Copilot]

@copilot fix these:

...

Fixed all clang-tidy errors in 8b71751:

• misc-use-anonymous-namespace: moved current_throw_trace, demangle_symbol, and format_stacktrace into anonymous namespace
• cppcoreguidelines-no-malloc / cppcoreguidelines-owning-memory: replaced manual free(demangled) with std::unique_ptr<char, FreeDeleter> RAII wrapper; added FreePtrArrayDeleter for backtrace_symbols result
• bugprone-multi-level-implicit-pointer-conversion: NOLINTNEXTLINE on the unavoidable free(char**) inside the deleter
• modernize-use-auto: changed static CxaThrowFn to static auto