Auto-memoize user @rx.memo components with stateful props

[masenf]

Type of change

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

Description

Extends the compiler's auto-memoization pass to wrap user-authored @rx.memo components when they're called with state-bound props or event handlers. This ensures state hooks compile into a generated wrapper instead of the page module, preventing unnecessary full-page re-renders on state changes.

Key changes:

1. Auto-memo wrapper generation (reflex/compiler/plugins/memoize.py):

   • Modified _should_memoize() to treat @rx.memo components as eligible for wrapping when bound to state
   • Generated wrappers opt out of being wrapped again via MemoizationDisposition.NEVER

2. Memo component definition (packages/reflex-base/src/reflex_base/components/memo.py):

   • Added auto_memo_wrapper flag to MemoComponentDefinition to distinguish compiler-generated wrappers from user code
   • Updated _get_memo_component_class() to apply NEVER disposition only to auto-generated wrappers, allowing user @rx.memo components to be wrapped when needed
   • Clarified docstring explaining the interaction between @rx.memo and auto-memoization

3. Passthrough wrapper creation (packages/reflex-base/src/reflex_base/components/memo.py):

   • Set auto_memo_wrapper=True when creating passthrough wrappers via create_passthrough_component_memo()

4. Documentation (docs/library/other/memo.md):

   • Added explanation of how state binding at call sites works with auto-memoization

Behavior

Before: A @rx.memo component called with a state Var would pull that state hook into the page module, causing the entire page to re-render on state changes.

After: The compiler detects this pattern and generates a wrapper that holds the state hooks. The page renders the wrapper, which re-renders on state changes and passes the prop to the memoized component. React's memo then skips the component unless the prop value actually changed.

Testing

• Added 6 comprehensive unit tests covering:
  • Auto-memo wrapper opt-out behavior
  • User memo with stateful props gets wrapped
  • User memo with static props stays inline
  • Event handler props use useCallback in wrapper
  • Children render in page scope, not captured
  • Memo inside foreach renders in foreach body
• Added 1 integration test (test_memo_stateful_prop_and_children_update) verifying the feature works end-to-end with both stateful props and children

All tests pass with adequate coverage.

Checklist

• Tests pass with adequate coverage
• uv run ruff check . and uv run ruff format . clean
• uv run pyright reflex tests passes
• pyi_hashes.json updated
• Documentation updated

https://claude.ai/code/session_01FNfPvVUGGMUQHh63V4Phbe

[greptile-apps]

Greptile Summary

The PR extends compiler auto-memoization to isolate stateful props and event handlers passed to user-authored @rx.memo components.

• Marks compiler-generated passthrough wrappers so they cannot be wrapped recursively.
• Keeps static memo calls inline while extracting stateful calls into generated wrappers.
• Adds unit, integration, documentation, and release-note coverage for the new behavior.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
packages/reflex-base/src/reflex_base/components/memo.py	Adds explicit generated-wrapper metadata and conditionally applies the recursion-prevention memoization disposition.
reflex/compiler/plugins/memoize.py	Allows user-authored memo components to pass through the existing stateful auto-memoization heuristic.
tests/units/compiler/test_memoize_plugin.py	Covers wrapper opt-out, stateful and static props, event callbacks, child passthrough, and foreach ownership.
tests/integration/tests_playwright/test_memo.py	Verifies that stateful memo props and children update correctly in the browser.
docs/library/other/memo.md	Documents how generated wrappers isolate call-site state dependencies.

_{Reviews (3): Last reviewed commit: "Merge remote-tracking branch 'origin/mai..." | Re-trigger Greptile}

[codspeed-hq]

Merging this PR will not alter performance

✅ 27 untouched benchmarks
⏩ 8 skipped benchmarks¹

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_{Comparing claude/auto-memoize-stateful-props-dqga0l (d982b97) with main (a4d99be)}

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. ↩

[cubic-dev-ai]

All reported issues were addressed across 6 files

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