corpus/round-trip/block-nodes/image-boundary.md

@@ -22,5 +22,5 @@ Taken from Kiruna.
 :::
 
 :::mediaSingle {layout=center}
-::media {type=external url="https://example.com/plan.png?a=1&b=2"}
+::media {type=external url="https://example.com/plan.png?a=1\u0026amp;b=2"}
 :::

corpus/round-trip/combinations/attribute-canonical.json

@@ -0,0 +1,60 @@
+{
+  "content": [
+    {
+      "attrs": {
+        "isNumberColumnEnabled": true,
+        "layout": "wide",
+        "width": 760.5
+      },
+      "content": [
+        {
+          "content": [
+            {
+              "attrs": {
+                "colspan": 2,
+                "colwidth": [
+                  340,
+                  420
+                ]
+              },
+              "content": [
+                {
+                  "content": [
+                    {
+                      "text": "Assembly",
+                      "type": "text"
+                    }
+                  ],
+                  "type": "paragraph"
+                }
+              ],
+              "type": "tableHeader"
+            }
+          ],
+          "type": "tableRow"
+        }
+      ],
+      "type": "table"
+    },
+    {
+      "attrs": {
+        "localId": "01a0-33_z",
+        "title": "a\nb\tc\"d\\e"
+      },
+      "content": [
+        {
+          "content": [
+            {
+              "text": "Notes.",
+              "type": "text"
+            }
+          ],
+          "type": "paragraph"
+        }
+      ],
+      "type": "expand"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/combinations/attribute-canonical.md

@@ -0,0 +1,11 @@
+:::::table {isNumberColumnEnabled=true layout=wide width="760.5"}
+::::tableRow
+:::tableHeader {colspan=2 colwidth="[340,420]"}
+Assembly
+:::
+::::
+:::::
+
+:::expand {localId=01a0-33_z title="a\nb\tc\"d\\e"}
+Notes.
+:::

corpus/round-trip/combinations/attribute-escapes.json

@@ -0,0 +1,41 @@
+{
+  "content": [
+    {
+      "content": [
+        {
+          "text": "a `b ",
+          "type": "text"
+        },
+        {
+          "attrs": {
+            "url": "c`d"
+          },
+          "type": "inlineCard"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "attrs": {
+            "url": "https://example.com/s?q=a&amp;b<c"
+          },
+          "type": "inlineCard"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "attrs": {
+        "extensionKey": "jira",
+        "parameters": {
+          "jql": "a|b `c` & d < e"
+        }
+      },
+      "type": "extension"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/combinations/attribute-escapes.md

@@ -0,0 +1,5 @@
+a `b :inlineCard{url="c\u0060d"}
+
+:inlineCard{url="https://example.com/s?q=a\u0026amp;b\u003cc"}
+
+::extension {extensionKey=jira parameters="{\"jql\":\"a\u007cb \u0060c\u0060 \u0026 d \u003c e\"}"}

corpus/round-trip/combinations/pipe-cell-whitespace.json

@@ -0,0 +1,107 @@
+{
+  "content": [
+    {
+      "content": [
+        {
+          "content": [
+            {
+              "content": [
+                {
+                  "content": [
+                    {
+                      "text": "Cell",
+                      "type": "text"
+                    }
+                  ],
+                  "type": "paragraph"
+                }
+              ],
+              "type": "tableHeader"
+            },
+            {
+              "content": [
+                {
+                  "content": [
+                    {
+                      "text": "Note",
+                      "type": "text"
+                    }
+                  ],
+                  "type": "paragraph"
+                }
+              ],
+              "type": "tableHeader"
+            }
+          ],
+          "type": "tableRow"
+        },
+        {
+          "content": [
+            {
+              "content": [
+                {
+                  "content": [
+                    {
+                      "text": " lead",
+                      "type": "text"
+                    }
+                  ],
+                  "type": "paragraph"
+                }
+              ],
+              "type": "tableCell"
+            },
+            {
+              "content": [
+                {
+                  "type": "paragraph"
+                }
+              ],
+              "type": "tableCell"
+            }
+          ],
+          "type": "tableRow"
+        },
+        {
+          "content": [
+            {
+              "content": [
+                {
+                  "content": [
+                    {
+                      "attrs": {
+                        "style": "a|b",
+                        "text": "ok"
+                      },
+                      "type": "status"
+                    }
+                  ],
+                  "type": "paragraph"
+                }
+              ],
+              "type": "tableCell"
+            },
+            {
+              "content": [
+                {
+                  "content": [
+                    {
+                      "text": "trail ",
+                      "type": "text"
+                    }
+                  ],
+                  "type": "paragraph"
+                }
+              ],
+              "type": "tableCell"
+            }
+          ],
+          "type": "tableRow"
+        }
+      ],
+      "type": "table"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/combinations/pipe-cell-whitespace.md

@@ -0,0 +1,4 @@
+| Cell | Note |
+| --- | --- |
+| :text{text=" "}lead |  |
+| :status[ok]{style="a\u007cb"} | trail:text{text=" "} |

spec/flavour.md

@@ -93,11 +93,14 @@ container is open, a named error otherwise.
 **Attributes**: `{key=value key2="two words"}`. `{attrs}` is optional in every form, and `{}` is
 valid — no attributes. A bare value matches `[A-Za-z0-9_-]+`; any other value is double-quoted
 with JSON string escaping (`\"` `\\` `\n` `\t` `\uXXXX`, …) — total over
-Unicode, and raw newlines never appear inside quotes. The closing `}` is the first one outside
-quotes, since a quoted value holds `}` unescaped. All values are strings at the grammar
-level; each node's section assigns types. Canonical form orders keys alphabetically, spells
-values bare wherever allowed, inside quotes escapes only what it must using the shortest escape
-form, and omits empty `{attrs}` except where the `{` itself claims the directive
+Unicode, and raw newlines never appear inside quotes. A quoted value also escapes `` ` ``, `&`,
+`<` and `|` as `\u0060`, `\u0026`, `\u003c` and `\u007c` — the code span, entity reference,
+autolink, raw HTML and pipe cell's split all bind at or before a directive does, so a raw one
+would reach back out of the value; `*`, `_`, `~`, `[` and `(` resolve after and stay raw. The
+closing `}` is the first one outside quotes, since a quoted value holds `}` unescaped. All values
+are strings at the grammar level; each node's section assigns types. Canonical form orders keys
+alphabetically, spells values bare wherever allowed, escapes inside quotes in the shortest form
+each escape has, and omits empty `{attrs}` except where the `{` itself claims the directive
 (`:hardBreak{}`).
 
 **Escaping**: the emitter backslash-escapes whatever literal text would otherwise parse as
@@ -219,9 +222,9 @@ One header row plus plain inline cells is a pipe table; anything richer is the d
 and every cell carry no attrs and no marks, the first row is all `tableHeader` and the rest all
 `tableCell`, every row has the header's cell count, and every cell holds exactly one attr-less,
 mark-less paragraph — an empty cell holds one empty paragraph — with no `|` anywhere the
-inline layer spells as syntax — a code span, a link destination or title, an inline directive's
-attributes: backslash escapes are inert there, so pipe form cannot spell that pipe and the table
-takes the directive form. A pipe table parses back to exactly that shape.
+inline layer spells as syntax — a code span, a link destination or title: backslash escapes are
+inert there, so pipe form cannot spell that pipe and the table takes the directive form. A pipe
+table parses back to exactly that shape.
 
 ```
 | Part | Qty |
@@ -238,8 +241,8 @@ inline layer's ordinary CommonMark escaping yields the pipe; each cell is the in
 one paragraph, trimmed; canonical form pads cells with single spaces and ends rows with `|`
 (optional in input). Named errors: a delimiter or body row whose cell count differs from the
 header's, and an alignment colon in the delimiter row — ADF holds no column alignment. In a
-pipe cell a hard break is `:hardBreak{}`, a literal `|` is `\|`, and `|` inside a quoted
-attribute value is `\u007c` (JSON has no `\|`).
+pipe cell a hard break is `:hardBreak{}` and a literal `|` is `\|`; a `|` inside a quoted
+attribute value is already `\u007c`, so the split never reaches it.
 
 The directive form nests cells as containers of block content inside `tableRow` containers:
 

src/adf-to-markdown.test.ts

@@ -402,8 +402,8 @@ test('spells a table as a pipe table only where every row and cell is plain', ()
   assert.ok(directive(adfToMarkdown(table(row(cell('tableHeader', text('a'), text('b')))))))
   assert.equal(code(adfToMarkdown(table(row(cell('tableHeader', { attrs: { localId: 'a' }, type: 'paragraph' }))))), 'unspelled-node-attribute')
   assert.equal(
-    markdown(adfToMarkdown(table(row(cell('tableHeader', { content: [{ type: 'blockCard' }], type: 'paragraph' }))))),
-    '| :adf{json="{\\"type\\":\\"blockCard\\"}"} |\n| --- |\n',
+    markdown(adfToMarkdown(table(row(cell('tableHeader', { content: [{ attrs: { url: 'a|b' }, type: 'blockCard' }], type: 'paragraph' }))))),
+    '| :adf{json="{\\"attrs\\":{\\"url\\":\\"a\\u007cb\\"},\\"type\\":\\"blockCard\\"}"} |\n| --- |\n',
   )
   assert.equal(code(adfToMarkdown(table(row(cell('tableHeader', { content: [{ text: '\fa', type: 'text' }], type: 'paragraph' }))))), 'unspellable-whitespace')
   assert.ok(directive(adfToMarkdown(table(row(cell('tableHeader', { attrs: { level: 1 }, type: 'heading' }))))))
@@ -411,10 +411,8 @@ test('spells a table as a pipe table only where every row and cell is plain', ()
   const marked = (mark: AdfMark): AdfDocument => table(row(cell('tableHeader', { content: [{ marks: [mark], text: 'l', type: 'text' }], type: 'paragraph' })))
   assert.ok(directive(adfToMarkdown(marked({ attrs: { href: 'https://example.com/?x|y' }, type: 'link' }))))
   assert.ok(directive(adfToMarkdown(marked({ attrs: { href: 'https://example.com/', title: 'a|b' }, type: 'link' }))))
-  const fallsBack = (node: AdfNode): boolean => directive(adfToMarkdown(table(row(cell('tableHeader', { content: [node], type: 'paragraph' })))))
-  assert.ok(fallsBack({ marks: [{ type: 'code' }], text: 'a|b', type: 'text' }))
-  assert.ok(fallsBack({ attrs: { style: 'a|b' }, type: 'status' }))
-  assert.ok(fallsBack({ attrs: { url: 'https://example.com/?a|b' }, type: 'blockCard' }))
+  const codeSpan: AdfNode = { marks: [{ type: 'code' }], text: 'a|b', type: 'text' }
+  assert.ok(directive(adfToMarkdown(table(row(cell('tableHeader', { content: [codeSpan], type: 'paragraph' }))))))
   assert.equal(markdown(adfToMarkdown(marked({ attrs: { href: 'https://example.com/x' }, type: 'link' }))), '| [l](https://example.com/x) |\n| --- |\n')
 })
 
@@ -427,6 +425,7 @@ test('spells an inline node as a directive with its content slot and attributes'
   assert.equal(emitted({ attrs: { id: '1f389', text: 'a]b' }, type: 'emoji' }), ':emoji[a\\]b]{id=1f389}\n')
   assert.equal(emitted({ attrs: { data: { url: 'https://example.com/' } }, type: 'inlineCard' }), ':inlineCard{data="{\\"url\\":\\"https://example.com/\\"}"}\n')
   assert.equal(emitted({ attrs: { height: 24 }, type: 'mediaInline' }), ':mediaInline{height=24}\n')
+  assert.equal(emitted({ attrs: { url: 'a`b&c<d|e' }, type: 'inlineCard' }), ':inlineCard{url="a\\u0060b\\u0026c\\u003cd\\u007ce"}\n')
 })
 
 test('refuses an inline node attribute no section spells', () => {

src/directive-attributes.ts

@@ -9,6 +9,9 @@ export type SpelledPairs = { fault: AttributeFault; pairs?: undefined } | { faul
 
 const bareToken = /^[A-Za-z0-9_-]+$/
 
+// spec/flavour.md, Attributes.
+const quotedEscapes = /[&<`|]/g
+
 export function isBareToken(text: string): boolean {
   return bareToken.test(text)
 }
@@ -53,5 +56,5 @@ export function spellStringAttribute(text: string): string {
 }
 
 function quote(text: string): string {
-  return JSON.stringify(text)
+  return JSON.stringify(text).replace(quotedEscapes, (character) => `\\u${character.charCodeAt(0).toString(16).padStart(4, '0')}`)
 }

src/markdown-escaping.ts

@@ -2,7 +2,7 @@ import { escapesLineClaim, isUnicodeWhitespace, opensBracketedAutolink, startsEn
 
 export type EmphasisRole = 'close' | 'open'
 
-export type InlineEscaping = 'attribute' | 'backslash' | 'bracketed' | 'none'
+export type InlineEscaping = 'backslash' | 'bracketed' | 'none'
 
 export type InlineSegment =
   | { emphasis: EmphasisRole; escaping: 'none'; mark: string; text: string }
@@ -128,7 +128,7 @@ function touchesSyntax(scan: string, escapings: readonly (InlineEscaping | undef
 }
 
 function isSyntax(escaping: InlineEscaping | undefined): boolean {
-  return escaping === 'attribute' || escaping === 'none'
+  return escaping === 'none'
 }
 
 function opensConstruct(scan: string, index: number, inBrackets: boolean, container: LineContainer, escaped: ReadonlySet<number>): boolean {

src/markdown-inline.ts

@@ -92,7 +92,7 @@ function carryEdges(segment: InlineSegment, leading: boolean, trailing: boolean)
 }
 
 function carriedText(text: string): InlineSegment {
-  return { escaping: 'attribute', text: spellLeafDirective('text', spellAttributes([['text', spellStringAttribute(text)]])) }
+  return syntax(spellLeafDirective('text', spellAttributes([['text', spellStringAttribute(text)]])))
 }
 
 function spellLeafDirective(name: string, attributes: string): string {

todo.md

@@ -96,24 +96,20 @@ detail is settled at its own milestone.
           `inline-directives.ts`, which holds four of the nine marks while the rest are branch
           literals in the emitter — and the parser (3) needs every name to make `:em[x]` the named
           error `spec/flavour.md` promises.
-    - [ ] **2e3 — Attribute canonicalization and the quoted value's escape.** Attribute
-          canonicalization, a pipe cell's whitespace edges, and `\u007c` for a `|` inside a quoted
-          attribute value. The rule is wider than the pipe: a quoted value spells `` ` ``, `&` and
-          `<` raw today, so a backtick pair in an `inlineCard`'s `data`, a `status`'s `style` or the
-          inline carry's `json` reads back as a code span, an entity or raw HTML inside the value.
-          One escape settles all four, and the pick decides whether a directive or a code span wins
-          where they overlap (3). `escaping: 'attribute'` earns its keep at that rule or collapses
-          into `none`: nothing the escaper does tells the two apart today, since a carried segment
-          holds only spaces, tabs and newlines.
+    - [x] **2e3 — Attribute canonicalization and the quoted value's escape.**
+          **Settled** (the maintainer, 2026-08-26): a quoted attribute value escapes `` ` ``, `&`,
+          `<` and `|` as `\u0060`, `\u0026`, `\u003c` and `\u007c`, in every directive, block and
+          inline alike — the constructs those four open all bind at or before a directive does, and
+          nothing else reaches into `{attrs}`. Emitted attributes being inert leaves 3 free to keep
+          CommonMark's own precedence between a directive and a code span, and collapsed
+          `escaping: 'attribute'` into `none`.
     - [ ] **2e4 — The carry's fallback triggers.** `spec/flavour.md` carries a node its section
           cannot spell — an attrs key no section lists, a value that is not the section's type, an
           arg slot holding no bare token, marks no nesting spells — where the emitter still refuses,
-          which leaves the refusals a container's own spelling owns. The carry spells
-          `escaping: 'none'`, which is what makes `tryPipeCell` refuse the pipe form for a carry
-          whose JSON holds a pipe. The flanking trigger 2e2 added to that list is the odd one out:
-          `unspellableMark` finds it after assembly and names a mark type against the line's path,
-          so the failing run needs identifying before the carry can replace the refusal
-          `corpus/unspellable/mark-inside-word` pins.
+          which leaves the refusals a container's own spelling owns. The flanking trigger 2e2
+          added to that list is the odd one out: `unspellableMark` finds it after assembly and
+          names a mark type against the line's path, so the failing run needs identifying before
+          the carry can replace the refusal `corpus/unspellable/mark-inside-word` pins.
     - [ ] **2e5 — Combined documents and the collision property.** Documents combining nodes rather
           than isolating one, and the gate's collision property: no two corpus documents may emit
           the same bytes — one spelling for two documents is a round-trip break no parser can undo,
@@ -142,14 +138,14 @@ detail is settled at its own milestone.
       every raw-HTML construct in input is an error result. The CommonMark spec suite runs
       against it from here (§10). The parser owes `~` the same `can_open`/`can_close` the emitter
       assumes — CommonMark flanking, as for `*` — which `spec/flavour.md` does not yet pin, and
-      the precedence between a directive and the constructs a raw attribute value opens inside it —
-      a code span, an entity, raw HTML — which one directive alone already reaches until 2e's
-      escape lands. Whether a claimed line interrupts a paragraph is pinned for the plain case and
-      unstated for the lazy one: a closing fence on the line after a blockquote's open paragraph is
-      lazy continuation in CommonMark, which would swallow the fence and leave the container
-      unclosed. 2e1's `closing-fence-line` orders its blockquote away from that edge meanwhile.
-      `src/` gets its hierarchy at the same split — `adf/`,
-      `markdown/`, `html/`, the grammar module shared inside `markdown/` — while the rename is
+      the precedence in input between a directive and a code span, an entity or raw HTML written
+      raw inside its attributes — 2e3's escape keeps emitted output clear of that collision, so the
+      pick binds input alone. Whether a claimed line interrupts a paragraph is pinned for the plain
+      case and unstated for the lazy one: a closing fence on the line after a blockquote's open
+      paragraph is lazy continuation in CommonMark, which would swallow the fence and leave the
+      container unclosed. 2e1's `closing-fence-line` orders its blockquote away from that edge
+      meanwhile. `src/` gets its hierarchy at the same split — `adf/`, `markdown/`, `html/`, the
+      grammar module shared inside `markdown/` — while the rename is
       still mechanical. Three files do not move whole: `block-directives.ts` and
       `inline-directives.ts` each hold a node table milestones 6-7 need in `adf/` beside a
       markdown spelling that belongs in `markdown/`, and `directive-attributes.ts` fuses the