feat: Add Python 3.15 to test matrix

[sentrivana]

1. Lazy imports

Tried manually testing with a lazy import of sentry_sdk, looked ok.

PYTHON_LAZY_IMPORTS=all

Guarding the optional httpcore import with an additional AttributeError now, since httpcore doesn't work with PYTHON_LAZY_IMPORTS=all.

Notified other frameworks/libraries:

• httpcore
• sqlalchemy

Other libraries/frameworks that are problematic under PYTHON_LAZY_IMPORTS=all but already have a tracking issue for 3.15 support:

• fastapi

Caveat: It's not 100% clear to me whether this forcing of PYTHON_LAZY_IMPORTS=all is something libraries are supposed to support, see also https://peps.python.org/pep-0810/#global-lazy-imports-control. Probably fine to wait for the ecosystem to stabilize a bit here, rather than patching everything to be ready on day one.

2. CI

Marked some test suites as not python 3.15 ready yet:

• langgraph, cohere: fail to install on 3.15
• statsig: hangs on 3.15
• anything otlp/otel: hangs on 3.15
• integration_deactivation: fails to install on 3.15

3. Misc

Ran the common test suite with PYTHON_LAZY_IMPORTS=all. Everything looked fine.

Issues

Closes https://linear.app/getsentry/issue/PY-2649/test-with-python-315
Closes https://linear.app/getsentry/issue/PY-2651/declare-support-for-315

[sentrivana]

While testing manually, I encountered the issue first pointed out here. Opened an httpcore discussion for it. Looking into a workaround or at least a way to fail gracefully if httpcore is installed for now.

[github-actions]

Codecov Results 📊

✅ 130404 passed | ⏭️ 7110 skipped | Total: 137514 | Pass Rate: 94.83% | Execution Time: 471m 19s

📊 Comparison with Base Branch

Metric	Change
Total Tests	📈 +32113
Passed Tests	📈 +31482
Failed Tests	—
Skipped Tests	📈 +631

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 2498 uncovered lines.
❌ Project coverage is 90.26%. Comparing base (base) to head (head).

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
- Coverage    90.27%    90.26%    -0.01%
==========================================
  Files          193       193         —
  Lines        25649     25649         —
  Branches      9454      9454         —
==========================================
+ Hits         23153     23151        -2
- Misses        2496      2498        +2
- Partials      1443      1445        +2

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Generated by Codecov Action

[linear-code]

PY-2649

PY-2651