Answer stability round 1: 0 🔴, 4 🟡; pin each HTML terminator boundary the readers keep

src/markdown/commonmark/backtick-runs.ts

@@ -8,7 +8,7 @@ export function backtickRun(text: string, index: number): number {
 // Readers ask with `from` rising, which keeps each length's cursor moving forward, so asking at every opener stays
 // linear in the text; an ask behind the cursor restarts that length from its first run.
 export function backtickCloser(text: string): (from: number, opener: number) => number | undefined {
-  const asked = new Map<number, number>()
+  const cursors = new Map<number, number>()
   const starts = new Map<number, number[]>()
   for (let start = text.indexOf('`'); start !== -1; ) {
     const length = runLength(text, start)
@@ -20,10 +20,10 @@ export function backtickCloser(text: string): (from: number, opener: number) =>
   return (from, opener) => {
     const runs = starts.get(opener)
     if (runs === undefined) return undefined
-    let at = asked.get(opener) ?? 0
+    let at = cursors.get(opener) ?? 0
     if ((runs[at - 1] ?? -1) >= from) at = 0
     while ((runs[at] ?? Infinity) < from) at += 1
-    asked.set(opener, at)
+    cursors.set(opener, at)
     return runs[at]
   }
 }

src/markdown/inline-tokens.test.ts

@@ -9,8 +9,13 @@ import { losslessMarkdownToAdf } from './parse/markdown-to-adf.ts'
 
 const constructs = ['<!A>', '<??>', '<![CDATA[]]>']
 
-test('an HTML construct whose terminator starts right after its opener reads as HTML', () => {
-  for (const construct of constructs) assert.equal(readInlineToken(inlineSource(`a ${construct}`), 2, flavourClaims.commonmark).kind, 'html', construct)
+// CommonMark 0.31.2, Raw HTML: the terminator must start after the opener, and may start right after it.
+test('an HTML opener reads as HTML only where its terminator starts after it', () => {
+  const cases: [string, string][] = [...constructs.map((text): [string, string] => [text, 'html']), ['<!---->', 'html'], ['?> <? ?>', 'html'], ['?> <?', 'text'], ['<?>', 'text']]
+  for (const [text, kind] of cases) {
+    const at = text.lastIndexOf('<')
+    assert.equal(readInlineToken(inlineSource(`a ${text}`), at + 2, flavourClaims.commonmark).kind, kind, text)
+  }
 })
 
 test('text spelling such a construct round-trips', () => {