Use TracePoint.allow_reentry to support TracePoint events while eval

[marshall-lee]

• Update Ruby and gems versions (needed to run a new test case using TracePoint API on new Rubies)

• Undefine alloc funcs of Context and ThreadsTable. This is to suppress a warning of this kind on modern rubies:

  warning: undefining the allocator of T_DATA class Byebug::ThreadsTable warning: undefining the allocator of T_DATA class Byebug::Context

• Use TracePoint.allow_reentry to support others' TracePoint events while evaling.

• Temporarily shut Byebug's TracePoint event handlers in the thread that issued allowing_other_threads { ... } to avoid infinite recursion in event handlers. CTX_FL_IGNORE flag was useful here.

• Add a test case using TracePoint.new(:class) hook inspired by @fxn's comment https://github.com/deivid-rodriguez/byebug/issues/564#issuecomment-497499214

Fixes #564

[d4rky-pl]

I have checked this PR in our codebase on some simple examples where Zeitwerk was previously failing and it seems to be working fine.

@deivid-rodriguez I know this gem has been essentially unmaintained since 2021 but is there any chance you could take a look? 🙏

[douglas]

Hello @deivid-rodriguez ! Just to echo @d4rky-pl comment above, could you take a look at this?

[AlexWayfer]

@deivid-rodriguez please, take a look, the issue is still here and it's annoying.

[deivid-rodriguez]

Hei! Sorry. Indeed I was not able to pay a lot of attention to this library recently. I'll review this PR and make a new release in the following weeks 👍.

[AlexWayfer]

@deivid-rodriguez friendly reminder. :slightly_smiling_face:

[fxn]

❤️

[AlexWayfer]

Great! Thank you. Waiting for a new release.

[marshall-lee]

@deivid-rodriguez THANKS