fix(app): pass Reflex app instance to lifespan task app parameter

[BABTUNA]

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Type of change

• Bug fix (non-breaking change which fixes an issue)

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Changes To Core Features:

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Description

This fixes lifespan task app injection so tasks that declare an app
parameter receive the Reflex app instance (rx.App) instead of the
Starlette wrapper.

Before:

• In _run_lifespan_tasks, tasks with an app parameter were called with
  the Starlette lifespan app object.
• This made app inconsistent with expected Reflex app behavior.

After:

• app parameter now receives self (the Reflex app instance).
• Added optional starlette_app parameter support for tasks that
  explicitly want the Starlette instance.

Tests

Added regression test:

• tests/units/app_mixins/test_lifespan.py
  • test_lifespan_task_app_param_receives_reflex_app_instance

Validation run:

• uv run pytest tests/units/app_mixins/test_lifespan.py -q
• uv run ruff check reflex/app_mixins/lifespan.py tests/units/app_mixins/ test_lifespan.py

Closes #6331

[greptile-apps]

Greptile Summary

This PR fixes lifespan task parameter injection so that tasks declaring an app parameter now receive the Reflex app instance (self) rather than the Starlette wrapper, and adds an optional starlette_app parameter for tasks that explicitly need the Starlette object. The change is minimal and targeted, with a regression test covering the primary fix.

Confidence Score: 5/5

Safe to merge — the fix is correct and non-breaking; only remaining feedback is a P2 test coverage suggestion.

The core logic change is a one-line substitution (app → self) and an additive starlette_app injection block. Both paths are straightforward and have no side-effects on existing callers. The single P2 finding (missing test for starlette_app injection) does not affect correctness.

No files require special attention.

Important Files Changed

Filename	Overview
reflex/app_mixins/lifespan.py	Renamed _run_lifespan_tasks parameter from app to starlette_app, updated app injection to pass self (Reflex instance), and added optional starlette_app injection support; logic is correct.
tests/units/app_mixins/test_lifespan.py	New regression test verifies app parameter receives the Reflex instance; missing coverage for starlette_app parameter and the combined app+starlette_app case.

Sequence Diagram

sequenceDiagram
    participant SA as Starlette (ASGI)
    participant LM as LifespanMixin._run_lifespan_tasks(starlette_app)
    participant T as Lifespan Task

    SA->>LM: call with starlette_app instance
    LM->>LM: inspect.signature(task)
    alt task has "app" param
        LM->>LM: partial(task, app=self) — Reflex instance
    end
    alt task has "starlette_app" param
        LM->>LM: partial(task, starlette_app=starlette_app) — Starlette instance
    end
    LM->>T: task()
    T-->>LM: coroutine / context manager / plain return

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_{Reviews (1): Last reviewed commit: "Pass Reflex app instance to lifespan tas..." | Re-trigger Greptile}

[masenf]

looks good. need a doc update in docs/utility_methods/lifespan_tasks.md

[BABTUNA]

lemme update the docs rn

[BABTUNA]

@masenf changes up !

[codspeed-hq]

Merging this PR will not alter performance

✅ 9 untouched benchmarks

---

_{Comparing BABTUNA:fix-6331-lifespan-app-instance (b7e06dd) with main (8f7ad9a)}

[masenf]

can we just instantiate a LifespanMixin directly? no need to define this class in each test