fix: address markdown renderer review findings

Restore the replaced pipeline's synthetic fence newline so a real trailing
blank line inside a fence survives CodeBlock's display trim, and pin it
plus header-only tables in the DOM-parity corpus. Route
extractMarkdownPlainText through parseGfm so the grammar has one source.
Document the fixture provenance check (all 46 fixtures reproduce
byte-identically from react-markdown at 9e8101b800), the deliberate
O(prefix) divergence memcmp, the per-arm scope of grammar consistency,
the React 18 MathML namespace limitation, and the prefix-equivalence
corpus constraint.
This commit is contained in:
07akioni
2026-08-06 14:58:33 +08:00
parent d1e4fb91d2
commit 31b99930d9
14 changed files with 152 additions and 21 deletions

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@@ -58,7 +58,10 @@ export interface IncrementalBlocks {
/**
* A block's render key: its absolute source start offset. A position-less
* node (a grammar is free to omit positions) falls back to a negative
* list-index key, which keeps sibling keys unique without inventing offsets.
* list-index key — unique within one update's tail, which is the only place
* the fallback can occur: freezing requires the cut block's position, so a
* position-less parse keeps every block in the tail (real grammars always
* stamp positions and never take this path).
*/
function blockKey(node: RootContent, base: number, index: number): number {
const offset = node.position?.start.offset
@@ -88,6 +91,12 @@ export class IncrementalMarkdownParser {
*/
update(text: string): IncrementalBlocks {
if (this.cached !== null && text === this.prevText) return this.cached
// Deliberate O(prefix) memcmp per update: sound divergence detection has
// to verify the whole retained prefix, and startsWith compares bytes two
// orders of magnitude faster than parsing them — the cost this class
// exists to remove. Passing append/reset deltas instead would push
// append bookkeeping across the session-projection seam for a check
// that stays sub-millisecond at realistic reply sizes.
if (!text.startsWith(this.prevText)) {
this.prevText = ''
this.tailStart = 0

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@@ -7,6 +7,12 @@
* adjustments KaTeX output relies on) turns it into a tree this module maps
* onto React elements — KaTeX output is a static span/MathML/SVG vocabulary
* with no raw user HTML, the same trust shiki's tree gets in CodeBlock.
*
* React 18 has no MathML support, so the `.katex-mathml` subtree's elements
* land in the HTML namespace — exactly as they did under the replaced
* hast-util-to-jsx-runtime pipeline. The visual arm is the `.katex-html`
* span tree; the MathML arm serves assistive technology, which reads it by
* tag name regardless of namespace.
*/
import { createElement } from 'react'

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@@ -1,9 +1,11 @@
/**
* The markdown renderer's two mdast grammars, one per rendering arm. Both are
* built from the same micromark extensions, so block boundaries and inline
* semantics are identical wherever a document (or a document tail) is parsed:
* the incremental streaming path, the settled path, and the plain-text
* projection all agree on where blocks start and end.
* The markdown renderer's two mdast grammars, one per rendering arm. Each
* arm is internally consistent — the incremental tail parses, the one-shot
* parses, and the plain-text projection of a given grammar always agree on
* where blocks start and end — and the settled grammar is the streaming one
* plus the math extensions, so the arms differ only where TeX delimiters
* begin a math construct (a `$$` block is a paragraph while streaming and a
* math block once settled, by design).
*/
import type { Root } from 'mdast'

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@@ -1,12 +1,12 @@
/**
* Markdown-to-plain-text projection for compact summaries and labels.
* Parsing shares the renderer's GFM grammar; raw HTML stays literal, links
* keep their labels, images keep alt text, and code keeps its source text.
* Parsing shares the renderer's streaming GFM grammar ({@link parseGfm}), so
* the projection strips exactly the markup the renderer would draw; raw HTML
* stays literal, links keep their labels, images keep alt text, and code
* keeps its source text.
*/
import { fromMarkdown } from 'mdast-util-from-markdown'
import { gfmFromMarkdown } from 'mdast-util-gfm'
import { gfm } from 'micromark-extension-gfm'
import { parseGfm } from './parse.ts'
/** Amount of parsed Markdown content returned by the extractor. */
export type MarkdownPlainTextMode = 'all' | 'first-line' | 'first-paragraph'
@@ -108,10 +108,7 @@ export function extractMarkdownPlainText(
options: MarkdownPlainTextOptions = {},
): string {
const { mode = 'all' } = options
const root = fromMarkdown(markdown, {
extensions: [gfm()],
mdastExtensions: [gfmFromMarkdown()],
}) as MarkdownNode
const root = parseGfm(markdown) as MarkdownNode
const all = fullText(root)
switch (mode) {
case 'all':

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@@ -279,7 +279,10 @@ function renderCode(node: Md.Code, key: Key, context: MarkdownRenderContext): Re
return (
<CodeBlock
key={key}
code={node.value}
// The replaced hast pipeline appended one synthetic newline that
// CodeBlock's display trim removes; feeding the bare value would make
// that trim eat a REAL trailing blank line inside the fence instead.
code={`${node.value}\n`}
lang={context.streaming ? undefined : lang}
copyLabel={context.codeLabels?.copyLabel}
copiedLabel={context.codeLabels?.copiedLabel}

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@@ -0,0 +1,37 @@
<div class="_markdown_404681">
<div class="_block_9aea57 md-code-block">
<div class="_bannerWrap_9aea57">
<div class="_banner_9aea57">
<div class="_infostring_9aea57">
<div class="_action_9aea57">
<button class="_copyButton_9aea57" type="button">
#text "复制"
<pre class="_plain_9aea57">
<code>
#text "kept blank line follows\n"
<div class="_block_9aea57 md-code-block">
<div class="_bannerWrap_9aea57">
<div class="_banner_9aea57">
<div class="_infostring_9aea57">
#text "ts"
<div class="_action_9aea57">
<button class="_copyButton_9aea57" type="button">
#text "复制"
<div>
<pre class="shiki css-variables" style="background-color:var(--shiki-background);color:var(--shiki-foreground)" tabindex="0">
<code>
<span class="line">
<span style="color:var(--shiki-token-keyword)">
#text "const"
<span style="color:var(--shiki-token-constant)">
#text " doubled"
<span style="color:var(--shiki-token-keyword)">
#text " ="
<span style="color:var(--shiki-token-constant)">
#text " true"
#text "\n"
<span class="line">
#text "\n"
<span class="line">
<p>
#text "after"

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@@ -0,0 +1,23 @@
<div class="_markdown_404681">
<div class="_block_9aea57 md-code-block">
<div class="_bannerWrap_9aea57">
<div class="_banner_9aea57">
<div class="_infostring_9aea57">
<div class="_action_9aea57">
<button class="_copyButton_9aea57" type="button">
#text "复制"
<pre class="_plain_9aea57">
<code>
#text "kept blank line follows\n"
<div class="_block_9aea57 md-code-block">
<div class="_bannerWrap_9aea57">
<div class="_banner_9aea57">
<div class="_infostring_9aea57">
<div class="_action_9aea57">
<button class="_copyButton_9aea57" type="button">
#text "复制"
<pre class="_plain_9aea57">
<code>
#text "const doubled = true\n\n"
<p>
#text "after"

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@@ -0,0 +1,11 @@
<div class="_markdown_404681">
<div class="_tableScroll_404681">
<table>
<thead>
<tr>
<th>
#text "a"
<th>
#text "b"
<p>
#text "after"

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@@ -0,0 +1,11 @@
<div class="_markdown_404681">
<div class="_tableScroll_404681">
<table>
<thead>
<tr>
<th>
#text "a"
<th>
#text "b"
<p>
#text "after"

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@@ -6,6 +6,15 @@
// normalization), so a fixture diff means a user-visible markdown style
// change and must be reviewed as such — never re-record to silence a
// refactor.
//
// Provenance is reproducible: the replaced pipeline last lived at commit
// 9e8101b800 (origin/master before the renderer swap merged). Checking out
// that ref in a worktree, copying this spec, and running it records all
// fixtures from react-markdown byte-identical to the ones committed here:
// git worktree add /tmp/parity origin/master --detach && cd /tmp/parity
// pnpm install && cp <this spec> packages/client/ui-primitives/tests/
// npx vitest run packages/client/ui-primitives/tests/markdown-dom-parity.spec.tsx
// diff -r <recorded fixtures> <this branch's fixtures> # byte-identical
import { cleanup, render } from '@testing-library/react'
import { afterEach, describe, expect, it } from 'vitest'
import { MarkdownText } from '@deepseek-ai/dsh-client-ui-primitives'
@@ -139,6 +148,21 @@ const CORPUS: Record<string, string> = {
' indented code block',
' second line',
].join('\n'),
'fence-trailing-blank-lines': [
'```',
'kept blank line follows',
'',
'```',
'',
'```ts',
'const doubled = true',
'',
'',
'```',
'',
'after',
].join('\n'),
'table-header-only': '| a | b |\n| --- | --- |\n\nafter',
'inline-code-with-newline': 'Spans `a\nb` across a line.',
'links-and-autolinks': [
'[https ok](https://example.com "with title") and [mailto ok](mailto:dev@example.com).',

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@@ -12,7 +12,15 @@ import { parseGfm } from '../src/markdown/parse.ts'
afterEach(cleanup)
/** A many-block document exercising every freeze-sensitive construct. */
/**
* A many-block document exercising every freeze-sensitive construct. The
* prefix-equivalence property below holds only while no reference or
* footnote definition lands on the far side of a freeze boundary from its
* use: a fresh mount parses everything in one tree while the live stream's
* frozen blocks are already baked (the fingerprint test demonstrates the
* documented deviation). Keep definitions adjacent to their references when
* extending this corpus.
*/
const STREAM_DOC = [
'# Title',
'',