gh-101821: Cover ast.main function

[sobolevn]

Couple of comments on the implementation:

• script_helper.run_python_until_end has @support.requires_subprocess() guard, so it is should be safe for envs where subprocess is not available
• os_helper.temp_dir is also widely used for temp files, it even catches OSError and warns about it

So, this new cases should not add any test falkiness or new failures 🙂

• Issue: ast.main is not covered #101821

[sobolevn]

Oh, \n is platform specific. Fixing!

[sobolevn]

@hauntsaninja can you please take a look? :)

[hauntsaninja]

Looks good! Weird that the default indentation is 3

[miss-islington]

Thanks @sobolevn for the PR, and @hauntsaninja for merging it 🌮🎉.. I'm working now to backport this PR to: 3.10, 3.11.
🐍🍒⛏🤖

[miss-islington]

Sorry, @sobolevn and @hauntsaninja, I could not cleanly backport this to 3.11 due to a conflict.
Please backport using cherry_picker on command line.
cherry_picker bb396eece44036a71427e7766fbb8e0247373102 3.11

[miss-islington]

Sorry @sobolevn and @hauntsaninja, I had trouble checking out the 3.10 backport branch.
Please retry by removing and re-adding the "needs backport to 3.10" label.
Alternatively, you can backport using cherry_picker on the command line.
cherry_picker bb396eece44036a71427e7766fbb8e0247373102 3.10

[hauntsaninja]

Thanks! Fine not to backport since there are already merge conflicts