[SumiRann1]

Issue number: closes #8590

Summary

Changes

SSMProvider._split_batch_and_decrypt_parameters (used by get_parameters_by_name) did _overrides = options or {}, which made _overrides the same object as the caller's per-parameter dict. The following writes of transform, decrypt and max_age therefore modified the user's input. On later calls, those stale values took precedence over the new global decrypt/transform.

This PR copies the dict instead (_overrides = {**(options or {})}), so the caller's input is never modified. I also added a regression test.

User experience

Before: reusing the same parameters dict (e.g. a module-level PARAMS = {...}, as in the docs) across invocations mutated it on the first call. A later call such as get_parameters_by_name(PARAMS, decrypt=True) silently fetched parameters without decryption, because the stale decrypt=False from the first call won.

After: the input dict is left untouched, and global decrypt/transform passed on each call are honored.

---

Checklist

• Type of change: bug fix (code change + test added)
• Regression test added: test_ssm_provider_get_parameters_by_name_does_not_mutate_input_and_honors_new_globals
• Test fails before the fix and passes after it
• Existing parameters tests pass locally (uv run pytest tests/functional/parameters)
• ruff format and ruff check pass
• No documentation change needed (behaviour now matches what the docs already describe)

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[boring-cyborg]

Thanks a lot for your first contribution! Please check out our contributing guidelines and don't hesitate to ask whatever you need.
In the meantime, check out the #python channel on our Powertools for AWS Lambda Discord: Invite link

[leandrodamascena]

Thanks @SumiRann1, nice first one! I ran the suite and checked a few extra cases with the stubber: the caller's dict stays untouched, a later decrypt=True or transform="json" is honored, and per-parameter overrides still win over the globals like before. I pushed a tiny commit fixing a typo that slipped into a comment (qparameters), nothing else.

Approving now. This goes out in 3.38.0, so it will sit here a bit before I merge. No need to rebase or touch anything, I'll take care of it and you'll get the credit in the release notes. Thank you!

[SumiRann1]

Got it! Thanks for pointing out

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.93%. Comparing base (2af58c0) to head (71e8bbf).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #8607   +/-   ##
========================================
  Coverage    96.93%   96.93%           
========================================
  Files          318      318           
  Lines        16067    16067           
  Branches      1433     1433           
========================================
  Hits         15575    15575           
  Misses         349      349           
  Partials       143      143           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[boring-cyborg]

Awesome work, congrats on your first merged pull request and thank you for helping improve everyone's experience!

[powertools-for-aws-oss-automation]

Awesome work, congrats on your first merged pull request and thank you for helping improve everyone's experience!