fix(latex): do not re-escape a dollar that is already escaped by anandghegde · Pull Request #15602 · toeverything/AFFiNE

anandghegde · 2026-09-13T17:32:46Z

Description

Split out of #15596 on review feedback — this is an independent, pre-existing bug in the currency pass, so it does not belong in that PR.

The currency pass escapes any $ followed by a digit without looking at what precedes it:

preprocessedContent = preprocessedContent.replace(/\$(?=\d)/g, '\\$');

When the dollar is already escaped, that turns an odd backslash run even:

input:  \$4        (an escaped dollar — the author wants a literal "$4")
output: \\$4       (a literal backslash, then an unescaped `$`)

MarkdownPreprocessorManager.process runs this before _markdownToAst, so remark-math sees that bare $ and can take it as an active delimiter — the opposite of what escaping it was for.

The fix

Escape only a dollar whose preceding backslash run is even, keeping the run itself:

preprocessedContent = preprocessedContent.replace(
  /(?<!\\)((?:\\\\)*)\$(?=\d)/g,
  '$1\\$'
);

(?<!\\) anchors the run to its start and ((?:\\\\)*) takes backslashes in pairs, so an odd run never matches. Behaviour that was already correct is untouched:

input	before	after
`costs $5 today`	`costs \$5 today`	unchanged
`costs \\$4 today` (even run — literal `\` then a real `$`)	`costs \\\$4 today`	unchanged
`costs \$4 today` (odd run — already escaped)	`costs \\$4 today`	`costs \$4 today`

Relationship to #15596

Both touch this file, so whichever lands second will need a trivial rebase:

Both add export to preprocessLatex (the same one-word change).
They edit different statements — fix(latex): keep inline math that starts with a digit (#15588) #15596 changes the protection regex above, this one changes the currency regex below.
Test files are deliberately named differently (latex-preprocessor.unit.spec.ts there, latex-currency-escape.unit.spec.ts here) so they do not collide. Happy to fold them into one file once both are in, if you'd prefer that.

I verified this bug is not introduced by #15596: \$4 preprocesses to \\$4 identically with and without that branch.

Checklist

I have signed the AFFiNE Contributor License Agreement — required before merge; the license/cla check must be green (how it works)
The PR targets the canary branch and its title follows Conventional Commits
Tests are added or updated where it makes sense
yarn lint and yarn typecheck pass locally
If the PR code includes AI-generated edits, I have carefully reviewed it to ensure that the scope of the PR is consistent with what is claimed in the title and description, and that there are no redundant or invalid implementations.
I agree that maintainers may close the PR without discussion if they consider the code quality to be too low.

Notes on the checklist

CLA: not signed yet — the repository owner is signing it; the license/cla check will go green once that happens.
Tests: 7 cases in latex-currency-escape.unit.spec.ts. Reverting only the regex fails exactly the three already-escaped cases and leaves the four guards (plain price, bare amount, two prices, even run) green — they are regression guards, not props. Full blocksuite/affine/all suite: 230 passing.
Lint/format: oxlint --deny-warnings and oxfmt --check are both clean on the two changed files.
Typecheck: clean for these files. For transparency, a full yarn typecheck on my machine also reports pre-existing @prisma/client errors under packages/backend/server; those come from my installing with --mode=skip-build (so prisma generate never ran) and are unrelated to this change.

Summary by CodeRabbit

Bug Fixes
- Improved LaTeX handling for currency values by escaping dollar signs only when required.
- Preserved already-escaped dollar signs and backslash sequences correctly.
Tests
- Added coverage for plain currency amounts, already-escaped dollar signs, and even backslash runs.

The currency pass escapes any `$` followed by a digit, without looking at what precedes it. When the dollar is already escaped, that turns an odd backslash run even: `\$4` becomes `\\$4`, which is a literal backslash followed by an unescaped `$`. The preprocessor runs before the markdown is parsed, so remark-math can then read that `$` as an active delimiter — the opposite of what escaping it was meant to achieve. Escape only a dollar whose preceding backslash run is even, preserving the run itself. An odd run already means the dollar is escaped, so it is left alone; `$4` and `\\$4` are unaffected. `preprocessLatex` is exported so the rule can be tested directly.

coderabbitai · 2026-09-13T17:33:08Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Advanced

Run ID: c320ebfd-650f-4de8-abd6-0f0d6bdb69c7

📥 Commits

Reviewing files that changed from the base of the PR and between 868acf8 and 6e036ea.

📒 Files selected for processing (2)

blocksuite/affine/all/src/__tests__/adapters/latex-currency-escape.unit.spec.ts
blocksuite/affine/blocks/latex/src/adapters/markdown/preprocessor.ts

Included review availability: Your plan provides up to 10 included reviews per hour; 9 remain after this review.

📝 Walkthrough

Walkthrough

The PR exports preprocessLatex, changes currency dollar escaping based on preceding backslash runs, and adds tests for plain, already-escaped, and even-run cases.

Changes

LaTeX currency escaping

Layer / File(s)	Summary
Preprocessor export `blocksuite/affine/blocks/latex/src/adapters/markdown/preprocessor.ts`	`preprocessLatex` is exported for direct testing.
Currency escaping and validation `blocksuite/affine/blocks/latex/src/adapters/markdown/preprocessor.ts`, `blocksuite/affine/all/src/__tests__/adapters/latex-currency-escape.unit.spec.ts`	The escaping regex handles even and odd preceding backslash runs. Tests cover plain dollar amounts, already-escaped dollars, and even backslash runs.

Priority: ⬇️ Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: l-sun

Merge Risk: ⚪ Minimal · up to 6e036

The currency escaping update preserves already escaped amounts while continuing to escape unescaped currency values. No actionable merge risk remains.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 2 files.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: preventing re-escaping of already escaped dollar signs in LaTeX preprocessing.

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darkskygit · 2026-09-19T11:07:07Z

 * @returns The preprocessed content
 */
-function preprocessLatex(content: string) {
+export function preprocessLatex(content: string) {


test can import this directly, no reason to export to global

darkskygit · 2026-09-19T11:08:29Z

+  test.each([
+    ['a plain price', 'costs $5 today', 'costs \\$5 today'],
+    ['a bare amount', '$4', '\\$4'],
+    ['two prices', 'costs $5 and $10', 'costs \\$5 and \\$10'],
+  ])('escapes %s', (_, markdown, expected) => {
+    expect(preprocessLatex(markdown)).toBe(expected);
+  });


missing tests for the case fixed in this pr

anandghegde requested a review from a team as a code owner September 13, 2026 17:32

github-project-automation Bot added this to AFFiNE Project Sep 13, 2026

github-actions Bot added the test Related to test cases label Sep 13, 2026

anandghegde mentioned this pull request Sep 13, 2026

fix(latex): keep inline math that starts with a digit (#15588) #15596

Merged

anandghegde force-pushed the fix/currency-escape-odd-backslash branch from 6e036ea to 18371c5 Compare September 15, 2026 16:40

darkskygit reviewed Sep 19, 2026

View reviewed changes

darkskygit merged commit 82f8ada into toeverything:canary Sep 19, 2026
3 checks passed

formicoidea mentioned this pull request Sep 28, 2026

latex: markdown preprocessor breaks inline math starting with a digit, and re-escapes an already-escaped dollar formicoidea/blocksuite-labre#414

Closed

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fix(latex): do not re-escape a dollar that is already escaped - #15602

fix(latex): do not re-escape a dollar that is already escaped#15602
darkskygit merged 1 commit into
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anandghegde:fix/currency-escape-odd-backslash

anandghegde commented Sep 13, 2026 •

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anandghegde commented Sep 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Description

The fix

Relationship to #15596

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anandghegde commented Sep 13, 2026 •

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