gh-138360: Fix test_free_threading for IO objects

[uhx]

• Issue: Incorrect implementation of truncate in test_free_threading for IO #138360

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[uhx]

@Eclips4 please add skip-news label & review

[picnixz]

I think it would make sense to have an issue, just for backports tracking. I'll create one.

[uhx]

@picnixz thanks a lot

[Eclips4]

@picnixz I don't think that we need any test case here. What do you think?

[picnixz]

I don't think that we need any test case here. What do you think?

Err, no? this PR is fine!

[miss-islington-app]

Thanks @uhx for the PR, and @sobolevn for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14.
🐍🍒⛏🤖

[miss-islington-app]

Sorry, @uhx and @sobolevn, I could not cleanly backport this to 3.14 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 7c92497e5c6d3d6c36721f554d09efffbe4bbc23 3.14

[miss-islington-app]

Sorry, @uhx and @sobolevn, I could not cleanly backport this to 3.13 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 7c92497e5c6d3d6c36721f554d09efffbe4bbc23 3.13

[picnixz]

@uhx Could you take care of the backports please? you'll need to find the tests (they could have moved somewhere else)

[uhx]

@picnixz sure thing, I took a quick look at it yesterday but didn't find anything.

I checked the PR that introduced this test and noticed that this change was not included into 3.14:

• gh-132551: make BytesIO object free-thread safe #132616 (comment)

I also couldn't find these changes in any of the versions (3.13, 3.14)

[picnixz]

Oh so they were only 3.15+, no need for backports for now! Thank for having a look. However, I think #132616 should have been backported as it's a bugfix IMO.