Fix a detected race condition in initialization.

[kalmard0]

This was found by compiling and running a toy project using clang's ThreadSanitizer (--tsan) feature.

I haven't investigated it in detail but from the looks of it, renderthread can in theory access m_singleThreaded before its correct value (false) is set. After this change, ThreadSanitizer no longer complains.

[bkaradzic]

I haven't investigated it in detail but from the looks of it, renderthread can in theory access m_singleThreaded before its correct value (false) is set. After this change,

If you look default value and code above you'll see it doesn't matter.

ThreadSanitizer no longer complains.

Using ThreadSanitizers and similar analyzers is actually pointless if you don't try to understand what's going on. Randomly moving code until they stop warnings is not good idea.

[kalmard0]

If you look default value and code above you'll see it doesn't matter.

It doesn't matter until someone decides to change the default value, I guess. But I respect your choice, as it's your project.

[mcourteaux]

I disagree. The sanitizer correctly detects a race condition. The fact that the value is overwritten from false to false, doesn't mean the code is inherently doing a suspicious thing. If you stand by the argument that the default value already was false, hence it's not a problem, then you should remove that assignment altogether.

This PR is a strict improvement over the current situation, and there is no harm in merging it. The alternative is removing the assignment.

Sanitizers are useful tools to discover bugs, and deliberately leaving a race condition in, just increases the noise when you work with them. Training people to ignore sanitizer warnings is not a good idea, if the fix is this simple. To me, it's similar bad practice to ignoring compiler warnings: most of the time, they are a bug.

[bkaradzic]

and deliberately leaving a race condition in, just increases the noise when you work with them.

Yes, it's there to eliminate these shallow analysis, where someone runs sanitizer without understanding what's going on.

I'm not going to react on uninformed sanitizer results, or AI suggestions...

See previous discussions: #1186, #1189, #1307.