Replace calls to putenv with setenv

[brightly-salty]

Fixes #18502 which could lead to memory leaks if left unchecked

in os.putenv(k, v), replaces calls to C putenv("k=v") with calls to C setenv(k, v, 1)

First time contributor here, let me know if anything else is needed of me

[timotheecour]

this PR also improves #18533 but doesn't fix it; followup PR welcome to remove tracking of environment (more complex change so requires a different PR)

[juancarlospaco]

First time contributor here

Welcome!, nice code. 🙂:+1:

let me know if anything else is needed

If you are at it, maybe check the = Bug, in another PR.

[brightly-salty]

Looks like the new behavior of os.putenv("foo=bar", "baz" will throw an OSError rather than setting foo to "". Is this correct or should it be changed?

[brightly-salty]

See https://man7.org/linux/man-pages/man3/setenv.3.html#ERRORS, I could match on the error code to be able to throw a ValueError instead if EINVAL is returned.

[timotheecour]

@brightly-salty see my reply in timotheecour#782 (comment); your PR fixes timotheecour#782 ; please add a test using doAssertRaises(OSError)

I could match on the error code to be able to throw a ValueError instead if EINVAL is returned.

out of scope for this PR, and probably not a good idea; other OS calls don't do that

[timotheecour]

LGTM

in future work, we could add an overload that exposes the overwrite param, it's a useful thing to be able to not overwrite if env var already exists; eg:

proc putEnv*(key, val: string, overwrite = true)

[Araq]

This needs to be tested on MSVC too, see also https://stackoverflow.com/questions/17258029/c-setenv-undefined-identifier-in-visual-studio

[Araq]

Note: I need to test this manually for MSCV before merging.

[Araq]

Can confirm that the tests work on Windows with MSCV.

[juancarlospaco]

Thanks for fixing it @brightly-salty 🙂