fix(rich-markdown-editor): strict, provenance-aware markdown paste

[waleedlatif1]

Summary

Pasting code-like text such as 5 * width * height was being italicized ("width" became emphasis) by StarterKit's lenient mark paste rules. This makes markdown paste strict and correct — matching Obsidian/Linear.

• Disable StarterKit's mark paste rules (enablePasteRules: false on both editor variants). Emphasis is owned by MarkdownPaste (strict CommonMark via marked) on the plain-text path and by real HTML tags on the DOM path. Input rules (typing *x* → italic) are unaffected — they're a separate mechanism.
• Provenance-aware paste gate. Structural markdown (headings, lists, tables, blockquotes, fenced code, links, **bold**) always parses from the plain-text sibling — our parser is more faithful for GFM alignment/escaping. Inline-only marks (`*_ ~~ ``) parse for a plain-text-only paste, but defer to a rich HTML sibling (its presence signals a rich source that may carry structure the plain text can't — so a copied table isn't flattened).

Behavior (verified)

• Renders: *italic*, _italic_, **bold**, __bold__, ~~strike~~, `code`, and all block constructs.
• Stays literal (strict CommonMark flanking): 5 * width * height, def foo(*args, **kwargs), snake_case, file_path_here, URLs with underscores.
• A copied table whose plain-text sibling contains an inline mark is preserved (not flattened).
• Typing, read-only, and code-block paste all behave correctly.

Type of Change

• Bug fix

Testing

Committed unit tests cover the full gate matrix (constructs render, inline-only defers to HTML, code-like text isn't emphasized, structural parses with an HTML sibling, read-only/code-block/empty). Behavior additionally verified end-to-end in a real-browser paste harness (25 cases + typing/input-rule audit).

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
docs	Skipped		Jul 7, 2026 2:49am

[cursor]

PR Summary

Medium Risk
User-facing paste behavior changes across both editor surfaces, but scope is limited to the rich markdown editor and is covered by an expanded unit test matrix.

Overview
Fixes pasted code-like text (e.g. 5 * width * height) being wrongly emphasized by turning off StarterKit mark paste rules (enablePasteRules: false on the file editor and modal field). Inline formatting on paste now goes through strict CommonMark parsing or real HTML, not StarterKit’s lenient rules; typing input rules are unchanged.

MarkdownPaste now splits clipboard detection into structural hints (headings, lists, tables, links, **bold**, etc.)—always parsed from text/plain, even when text/html is present—and inline-only hints (*italic*, ~~strike~~, `code`), which parse only for plain-text-only pastes and defer to the HTML path when a rich sibling exists so tables and other structure aren’t flattened. Pastes inside inline code are skipped like code blocks.

Tests cover the full gate matrix: inline marks render on plain paste, defer with HTML, code-like strings stay literal under strict flanking, and inline-code paste stays literal.

^{Reviewed by Cursor Bugbot for commit aefb444. Configure here.}

[greptile-apps]

Greptile Summary

This PR replaces StarterKit's lenient mark paste rules with a provenance-aware two-tier markdown paste gate, fixing the bug where code-like expressions such as 5 * width * height were incorrectly italicized on paste.

• STRUCTURAL_MARKDOWN_HINTS (headings, **bold**, links, lists, blockquotes, fenced code, GFM tables) always force the strict marked-based parser, even when an HTML sibling is present — preserving GFM table alignment and custom escaping.
• INLINE_MARK_HINTS (*italic*, _italic_, ~~strike~~, `code`) parse only when no HTML sibling exists; if an HTML sibling is present the DOM path is used so rich structure is not flattened.
• enablePasteRules: false is added to both editor variants to disable StarterKit's lenient mark paste rules; a new guard on editor.isActive('code') prevents the handler from intercepting pastes inside inline-code spans.

Confidence Score: 5/5

The change is safe to merge — it narrows a paste interception bug with a well-structured two-tier gate backed by a comprehensive test suite covering every branch of the new logic.

The two-tier gate (structural vs. inline-only), the HTML-sibling deferral, and the inline-code guard all correctly handle the edge cases described. The marked strict-CommonMark parser preserves non-markdown text byte-for-byte, so the over-claiming in INLINE_MARK_HINTS is provably safe. Tests cover the full gate matrix including the new paths. No data-loss or auth risk is introduced.

No files require special attention.

Important Files Changed

Filename	Overview
apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/markdown-paste.ts	Core logic rewritten: splits hints into STRUCTURAL (always parse) and INLINE (defer to HTML sibling if present), adds inline-code guard. Logic is sound and well-commented.
apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/markdown-paste.test.ts	Test suite expanded with the full gate matrix: inline-code guard, deferral to HTML sibling, byte-for-byte literal pass-through for space-flanked asterisks/kwargs/snake_case, and underscore bold/italic variants.
apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/rich-markdown-editor.tsx	Single-line change: adds enablePasteRules: false to the useEditor options to disable StarterKit's lenient mark paste rules.
apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/rich-markdown-editor/rich-markdown-field.tsx	Single-line change: adds enablePasteRules: false to the useEditor options, mirroring the editor variant for consistency.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
A[Paste event] --> B{editor.isEditable?}
B -- No --> Z[return false\ndefault handler]
B -- Yes --> C{isActive codeBlock\nor inline code?}
C -- Yes --> Z
C -- No --> D{text/plain present?}
D -- No --> Z
D -- Yes --> E{STRUCTURAL_MARKDOWN_HINTS\nmatch?}
E -- Yes --> H[parseMarkdownToDoc\nmarked / strict CommonMark]
E -- No --> F{INLINE_MARK_HINTS\nmatch?}
F -- No --> Z
F -- Yes --> G{text/html sibling\npresent?}
G -- Yes --> Z2[return false\nDOM path handles HTML sibling]
G -- No --> H
H --> I{doc has content?}
I -- No --> Z
I -- Yes --> J[insertContent\nreturn true]

Loading

%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
flowchart TD
A[Paste event] --> B{editor.isEditable?}
B -- No --> Z[return false\ndefault handler]
B -- Yes --> C{isActive codeBlock\nor inline code?}
C -- Yes --> Z
C -- No --> D{text/plain present?}
D -- No --> Z
D -- Yes --> E{STRUCTURAL_MARKDOWN_HINTS\nmatch?}
E -- Yes --> H[parseMarkdownToDoc\nmarked / strict CommonMark]
E -- No --> F{INLINE_MARK_HINTS\nmatch?}
F -- No --> Z
F -- Yes --> G{text/html sibling\npresent?}
G -- Yes --> Z2[return false\nDOM path handles HTML sibling]
G -- No --> H
H --> I{doc has content?}
I -- No --> Z
I -- Yes --> J[insertContent\nreturn true]

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^{Reviewed by Cursor Bugbot for commit aefb444. Configure here.}