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

[chatgpt-codex-connector]

Codex usage limits have been reached for code reviews. Please check with the admins of this repo to increase the limits by adding credits.
Credits must be used to enable repository wide code reviews.

[codspeed-hq]

Merging this PR will not alter performance

✅ 26 untouched benchmarks
⏩ 8 skipped benchmarks¹

---

_{Comparing harsh21234i:fix/shared-state-root-dirty-6392 (de32980) with main (333b78b)}

Footnotes

1. 8 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]

Greptile Summary

The PR prevents temporary router dependency resolution from contaminating regular linked/shared-state event deltas and adds regression coverage for normal and exceptional cleanup.

• Snapshots dirty bookkeeping across the loaded state tree before resolving router-dependent values.
• Restores root bookkeeping after regular linked-state resolution and restores descendant bookkeeping when resolution fails.
• Adds tests covering ordinary root cleanup and both root and descendant exception paths.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains; the current exception path restores the snapshotted dirty bookkeeping for the root and loaded descendants before propagating the resolution error.

Important Files Changed

Filename	Overview
reflex/istate/shared.py	Preserves regular-event dirty state and restores all snapshotted descendants on exceptional delta resolution, addressing both prior review threads.
tests/units/test_state.py	Adds focused regression tests for ordinary root cleanup and exceptional root and descendant cleanup.
news/6841.bugfix.md	Accurately documents the linked/shared-state dirty-delta fix.

_{Reviews (7): Last reviewed commit: "Remove unrelated Pillow news fragment" | Re-trigger Greptile}

[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>