Avoid root dirty delta for shared state events

[harsh21234i]

Summary

• Preserve and restore root dirty state around the temporary router dirtying used by linked/shared state patching.
• Prevent regular linked-state events from sending an unchanged root/router delta.
• Add regression coverage for the issue described in Events against SharedState should not mark root state dirty all the time #6392.

Tests

• uv run --frozen pytest tests/units/test_state.py::test_linked_state_event_does_not_dirty_root_state -q
• uv run --frozen pytest tests/units/test_state.py::test_linked_state_event_does_not_dirty_root_state tests/units/test_state.py::test_router_var_dep tests/units/test_state.py::test_computed_var_depends_on_parent_non_cached tests/units/test_state.py::test_async_computed_var_get_state -q
• uv run --frozen pytest tests/units/test_state.py -q
• uv run --frozen pre-commit run --files reflex/istate/shared.py tests/units/test_state.py news/6841.bugfix.md

Closes #6392

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[codspeed]

Merging this PR will degrade performance by 17.19%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

❌ 5 regressed benchmarks
✅ 141 untouched benchmarks
⏩ 18 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	test_modify_state[linked]	17.1 ms	21.6 ms	-21.11%
❌	test_process_event[linked_1_client]	15.8 ms	19.5 ms	-18.92%
❌	test_process_event[linked]	8.6 ms	10.5 ms	-18.01%
❌	test_process_event[linked_8_clients]	75.9 ms	91.9 ms	-17.39%
❌	test_link_and_unlink[private]	6.1 ms	6.8 ms	-10.11%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing harsh21234i:fix/shared-state-root-dirty-6392 (078c9fd) with main (52d1c1c)}

Footnotes

1. 18 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[greptile-apps]

Confidence Score: 5/5

[Medium risk] Fixes state delta leakage in shared state events.

The PR appears safe to merge; no new actionable issue was identified.

Summary

The PR prevents temporary router dirtiness from appearing in linked/shared-state event deltas and adds regression coverage. The change since the previous review also avoids invoking fan-out when there are no affected tokens.

_{Reviews (22) · Last reviewed commit: "Merge upstream main into shared state fi..."}

[cubic-dev-ai]

All reported issues were addressed across 3 files

<sub>Reply with feedback, questions, or to request a fix.

Fix all with cubic | Re-trigger cubic</sub>

[harsh21234i]

hey @masenf The state-dirty cleanup changes and regression tests are now implemented, including descendant cleanup when delta resolution fails. Most CI checks are passing, but reflex-install-and-init is failing. Could you confirm whether that failure is infrastructure-related or requires a code change? Once it passes, could you please review the latest commit?

[masenf]

patch breaks delta calculation for computed vars in shared state that depend on root state.

see https://github.com/reflex-dev/reflex/blob/claude/substate-dirty-tracking-demo-rple7z/shared_state_router_delta_repro.py

[cubic-dev-ai]

All reported issues were addressed across 2 files (changes from recent commits).

<sub>Tip: Review your code locally with the cubic CLI to iterate faster.

Re-trigger cubic</sub>

[cubic-dev-ai]

All reported issues were addressed across 2 files (changes from recent commits).

<sub>Tip: Review your code locally with the cubic CLI to iterate faster.

Re-trigger cubic</sub>

[cubic-dev-ai]

All reported issues were addressed across 2 files (changes from recent commits).

<sub>Tip: Review your code locally with the cubic CLI to iterate faster.

Re-trigger cubic</sub>

[cubic-dev-ai]

All reported issues were addressed across 2 files (changes from recent commits).

<sub>Tip: Review your code locally with the cubic CLI to iterate faster.

Re-trigger cubic</sub>

[harsh21234i]

hey @mansef could you please review the latest commit?

[cubic-dev-ai]

All reported issues were addressed across 3 files

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>