Fix unclosed Session file descriptor leak in RequestsClient (fixes #874)

[Jah-yee]

Summary

Fixes file descriptor / socket leak in stripe-python when using the requests client.

Problem

The RequestsClient stores a requests.Session in a thread-local variable (self._thread_local.session). This Session is created on first use but never closed, causing:

• ResourceWarning: unclosed <ssl.SSLSocket> on Python exit
• File descriptor leaks for long-running processes

Solution

Register atexit.register(self.close) in RequestsClient.__init__() to ensure the thread-local Session is properly closed when Python exits.

Changes

• stripe/_http_client.py:
  • Added import atexit
  • Added atexit.register(self.close) in RequestsClient.__init__

Testing

import stripe
stripe.api_key = "placeholder"
with contextlib.suppress(Exception):
    stripe.Account.list()
# Before fix: ResourceWarning about unclosed SSL socket
# After fix: No warning

References

• Issue: stripe api with requests leaks socket file descriptors via unclosed Session #874
• Original report: @fm hysteria in stripe api with requests leaks socket file descriptors via unclosed Session #874

[Jah-yee]

Gentle ping @richardlawrence @ob-stripe @cjavilla-stripe — this PR fixes unclosed Session file descriptor leak in RequestsClient (fixes #874). Looking forward to your review! 🙏

[Jah-yee]

Hi! Just following up on this PR. The fix addresses an unclosed file descriptor leak in RequestsClient (issue #874). CI is green. Happy to make any adjustments if needed!

[xavdid]

Thank you for the submission! We'll have to take a look to see if the performance characteristics mentioned in the original issue have changed since it was filed. That may take us some time, since there's a lot else on our plate right now.

[Jah-yee]

Friendly ping @jar-stripe — just checking in on this PR. Happy to make any adjustments if needed! 🙏

[xavdid]

@Jah-yee I've already replied above- please stop pinging maintainers.