fix: make Markdown a MemoizationLeaf so Var children stay inlined

[FarhanAliRaza]

react-markdown asserts its children prop is a string. Without the snapshot boundary, the auto-memoize plugin hoists a Var child into its own Bare_comp_ element, which renders as [object Object] and crashes the subtree.

All Submissions:

• Have you followed the guidelines stated in CONTRIBUTING.md file?
• Have you checked to ensure there aren't any other open Pull Requests for the desired changed?

Type of change

Please delete options that are not relevant.

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

New Feature Submission:

• Does your submission pass the tests?
• Have you linted your code locally prior to submission?

Changes To Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your core changes, as applicable?
• Have you successfully ran tests with your changes locally?

closes #6531

fixes ENG-9539

[greptile-apps]

Greptile Summary

This PR fixes a runtime crash where rx.markdown(State.var) would render [object Object] instead of the Var's string value. The root cause was the auto-memoize plugin hoisting the Var child into a Bare_comp_<hash> React element, while react-markdown requires its children prop to be a string.

• Core fix: Markdown now inherits from MemoizationLeaf instead of Component, which sets _memoization_mode = MemoizationMode(recursive=False) and keeps any Var child inlined in the snapshot body rather than being hoisted out as a separate React element.
• Tests: A unit test that runs the full compiler pipeline and asserts no Bare_comp_ is emitted, plus a Playwright integration test that verifies the rendered text and that [object Object] is never visible.

Confidence Score: 5/5

The change is minimal and correctly targeted: swapping the base class for Markdown to MemoizationLeaf prevents the auto-memoize plugin from hoisting Var children out as separate React elements, which was the source of the crash.

The fix is a single-line base-class change backed by two levels of tests (a full-compiler unit test and a Playwright integration test). The two review comments flag test-quality concerns — a potential state-name collision in repeated test runs and reliance on internal compiler APIs — neither of which affects production behavior.

The test helper _compile_page_output in tests/units/components/markdown/test_markdown.py accesses several internal compiler APIs that could drift; it warrants a second look if compiler internals are refactored.

Important Files Changed

Filename	Overview
packages/reflex-components-markdown/src/reflex_components_markdown/markdown.py	Single-line base-class change from Component to MemoizationLeaf; docstring updated to explain the snapshot-boundary rationale. No logic changes.
tests/units/components/markdown/test_markdown.py	Adds _compile_page_output helper and test_markdown_var_child_inlined_not_wrapped that run the full compiler pipeline; accesses several internal APIs that could shift independently of this fix.
tests/integration/tests_playwright/test_memoize_edge_cases.py	Adds state variable + event handler for markdown source, a Var-driven rx.markdown component, and a Playwright test that verifies initial render and state-update behavior.
pyi_hashes.json	Hash for markdown.pyi updated to reflect the base-class change; mechanical bookkeeping.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["rx.markdown(State.var)"] --> B{Markdown base class}
    B -->|Before: Component| C["Auto-memoize plugin scans children"]
    C --> D["Var child hoisted into Bare_comp_hash React element"]
    D --> E["ReactMarkdown receives JSX element as children"]
    E --> F["Renders as '[object Object]' / crash"]
    B -->|After: MemoizationLeaf| G["_memoization_mode = recursive=False"]
    G --> H["Var child stays inlined in snapshot body"]
    H --> I["ReactMarkdown receives string interpolation as children"]
    I --> J["Renders correctly"]

Loading

_{Reviews (1): Last reviewed commit: "fix: make Markdown a MemoizationLeaf so ..." | Re-trigger Greptile}

[codspeed-hq]

Merging this PR will not alter performance

✅ 24 untouched benchmarks

---

_{Comparing FarhanAliRaza:markdown-component-memo-fix (5aa7159) with main (6112083)}