[pabloDeputter]

Description

Path-style handlers, e.g. SENTRY_INITIAL_HANDLER=app/index.handler, were manually loaded and never cached unlike dotted handlers, e.g. index.handler which automatically ended up in sys.modules; so module was loaded again on every warm invocation and state was lost.

Changes & Results

Loader now does the same as Lambda runtime itself: / is turned into . and importlib.import(...) is called; Python caches the module, so it runs exactly once per execution environment.

Some results below on a Lambda function (python3.13, arm64, 512 MB) that creates 3 boto3 clients at import:

Warm invocations: p50 122ms => 58ms; p99 180ms => 69ms.

Cold starts remain the same, 1.4s for both.

Peak memory also drops from 117 MB => 108 MB and is fixed on invocations, unlike the old layer which grows over time because each call creates new clients.

Issues

Resolves #8079 & PY-3016

[github-actions]

Coverage Results 📊

✅ 138998 passed | ⏭️ 7669 skipped | Total: 146667 | Pass Rate: 94.77% | Execution Time: 458m 55s

📊 Comparison with Base Branch

Metric	Change
Total Tests	📈 +1552
Passed Tests	📈 +1554
Failed Tests	—
Skipped Tests	📉 -2

All tests are passing successfully.

✅ Patch coverage is 100.00% (no changed executable lines found; target 80%).
Project statement coverage is 90.24% (down 0.01 percentage points from base (63707d7) to head (fb3fbfd)).

Coverage diff

@@            Coverage Diff             @@
##        master     #8134       +/-##
==========================================
- Coverage    90.25%    90.24%    -0.01%
==========================================
  Files          203       203         —
  Tracked lines     27114     27114         —
  Branches     10136     10136         —
==========================================
- Hits         24470     24468        -2
- Misses        2644      2646        +2
- Partials      1538      1540        +2

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