Data race when multiple threads write to log files

[jfilby]

I've found that Chronicles can have a race condition, where memory gets corrupted, when logging from multiple threads. This is even with each thread logging to its own file. This leads to threads dying, often silently.

Attached is a test case that reproduces this issue. You may have to run it multiple times, but most of the time the test doesn't finish for me (no error or exception), the program just dies. Sometimes it does generate an exception when something breaks (because of the memory being corrupted).

I found the cause of the problem by using valgrind --tool-helgrind on Linux which shows data race errors in a larger program I'm testing. The issue happens on Windows too.

[jfilby]

Attached is the test case source and the results from running the test with valgrind --tool-helgrind on Linux.
chronicles_data_race_test.zip
helgrind.zip