bpo-34113: Fix SIGSEGV on negative STACKADJ when LLTRACE is on

[costypetrisor]

https://bugs.python.org/issue34113

https://bugs.python.org/issue34113

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[costypetrisor]

cc @vstinner

[encukou]

Can you also add a test that fails without this change?

[costypetrisor]

@encukou I pushed a new test which without the fix would crash

[vstinner]

please remove this empty line

[costypetrisor]

Done :)

[vstinner]

the function already checks status. in fact, you don't need the function result: "status, stdout, stderr = " can be removed IMHO.

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A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

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[costypetrisor]

I have made the requested changes; please review again
:)

[bedevere-bot]

Thanks for making the requested changes!

@vstinner: please review the changes made to this pull request.

[vstinner]

Hum. I'm confused. Why do you write "LLTRACE" with 2 L whereas the constant only contains 1 L? If it's a typo, would you mind to rename the test file, test case and test method?

[vstinner]

Oh, LLTRACE comes from a C define:

#define LLTRACE  1      /* Low-level trace feature */

LL as Low-Level, I see. It's just surprising that the constant is called ltrace with a single L :-)

[costypetrisor]

@vstinner I was confused about this during the sprint too. Petr Viktorin who was sitting next to me didn't knew why this was written like this either.

So from what I understand the gist is that LLTRACE is the feature coming from Low Level Trace, but the global that you set in the console interpretor is __ltrace__ with just 1 lower-case L.