Read the container blocks, and part a nested list the tight spelling would swallow

src/markdown/emit/adf-to-markdown.test.ts

@@ -159,8 +159,8 @@ test('breaks a mark run at the node it carries', () => {
 test('refuses a carried node nested deeper than the emitter carries', () => {
   let node: AdfNode = { type: 'blockCard' }
   for (let depth = 0; depth < 600; depth += 1) node = { content: [node], type: 'blockCard' }
-  assert.equal(code(adfToMarkdown(document(node))), 'unsupported-node-shape')
-  assert.equal(code(adfToMarkdown(document(paragraph(node)))), 'unsupported-node-shape')
+  assert.equal(code(adfToMarkdown(document(node))), 'unsupported-nesting-depth')
+  assert.equal(code(adfToMarkdown(document(paragraph(node)))), 'unsupported-nesting-depth')
 })
 
 test('refuses a node whose content model the canonical form cannot emit', () => {
@@ -261,19 +261,19 @@ test('refuses a node carrying one mark type twice', () => {
   assert.equal(code(adfToMarkdown(document(paragraph({ marks: [em, em], text: 'x', type: 'text' })))), 'unsupported-node-shape')
 })
 
-test('refuses a nested list the tight spelling would swallow', () => {
+test('parts a nested list the tight spelling would swallow from the block above it', () => {
   const item = (...content: AdfNode[]): AdfNode => ({ content, type: 'listItem' })
   const text = (value: string): AdfNode => ({ content: [{ text: value, type: 'text' }], type: 'paragraph' })
   const outer = (...content: AdfNode[]): AdfDocument => document({ content: [item(...content)], type: 'bulletList' })
   const ordered: AdfNode = { attrs: { order: 2 }, content: [item(text('b'))], type: 'orderedList' }
-  assert.equal(code(adfToMarkdown(outer(text('a'), ordered))), 'unspellable-line-start')
-  assert.equal(code(adfToMarkdown(outer(text('a'), { content: [item()], type: 'bulletList' }))), 'unspellable-line-start')
+  assert.equal(markdown(adfToMarkdown(outer(text('a'), ordered))), '- a\n\n  2. b\n')
+  assert.equal(markdown(adfToMarkdown(outer(text('a'), { content: [item()], type: 'bulletList' }))), '- a\n\n  -\n')
   assert.equal(markdown(adfToMarkdown(outer(text('a'), { content: [item(text('b'))], type: 'bulletList' }))), '- a\n  - b\n')
 })
 
 test('refuses marks and attributes nested deeper than the emitter carries', () => {
   const marks: AdfMark[] = Array.from({ length: 600 }, (_, index) => ({ type: index % 2 === 0 ? 'em' : 'strong' }))
-  assert.equal(code(adfToMarkdown(document(paragraph({ marks, text: 'x', type: 'text' })))), 'unsupported-node-shape')
+  assert.equal(code(adfToMarkdown(document(paragraph({ marks, text: 'x', type: 'text' })))), 'unsupported-nesting-depth')
   let attrs: AdfMark['attrs'] = { depth: 'x' }
   for (let depth = 0; depth < 600; depth += 1) attrs = { depth: attrs }
   assert.equal(code(adfToMarkdown(document(paragraph({ marks: [{ attrs, type: 'em' }], text: 'x', type: 'text' })))), 'not-an-adf-document')
@@ -380,7 +380,7 @@ test('spells one code span over a run of code-marked nodes', () => {
 test('refuses a document nested deeper than the emitter carries', () => {
   let node: AdfNode = paragraph({ text: 'x', type: 'text' })
   for (let depth = 0; depth < 600; depth += 1) node = { content: [node], type: 'blockquote' }
-  assert.equal(code(adfToMarkdown(document(node))), 'unsupported-node-shape')
+  assert.equal(code(adfToMarkdown(document(node))), 'unsupported-nesting-depth')
 })
 
 test('emits an empty list item without trailing whitespace', () => {

src/markdown/emit/adf-to-markdown.ts

@@ -31,7 +31,7 @@ export function adfToMarkdown(document: AdfDocument): Result<string> {
 }
 
 function emitBlocks(nodes: readonly AdfNode[], container: BlockContainer, path: ConvertErrorPath, depth: number): Result<EmittedBody> {
-  if (depth > largestNesting) return failure('unsupported-node-shape', `the document nests deeper than the ${largestNesting} levels the emitter carries`, path)
+  if (depth > largestNesting) return failure('unsupported-nesting-depth', `the document nests deeper than the ${largestNesting} levels the emitter carries`, path)
   const blocks: PlacedBlock[] = []
   for (const [index, node] of nodes.entries()) {
     const nodePath = [...path, 'content', index]
@@ -60,12 +60,7 @@ function separationBetween(previous: PlacedBlock, next: PlacedBlock, container:
     if (previous.node.type === next.node.type) {
       return failure('unspellable-adjacent-lists', `two adjacent ${next.node.type} nodes read back as one list`, next.path)
     }
-    if (container === 'list-item') {
-      if (!interruptsParagraph(next.node)) {
-        return failure('unspellable-line-start', `a ${next.node.type} that cannot interrupt the block above it has no tight spelling`, next.path)
-      }
-      return success('\n')
-    }
+    if (container === 'list-item') return success(interruptsParagraph(next.node) ? '\n' : '\n\n')
   }
   if (container !== 'directive' || plainPair) return success('\n\n')
   if (previous.spelling === 'directive' && next.spelling === 'directive') return success('\n')

src/markdown/emit/inline-line.ts

@@ -140,7 +140,7 @@ function refuseContentAndText(node: AdfNode, path: ConvertErrorPath): Result<nul
 
 function emitRun(nodes: readonly AdfNode[], depth: number, firstIndex: number, context: InlineContext): Result<Emission> {
   if (depth > largestNesting) {
-    return failure('unsupported-node-shape', `the marks nest deeper than the ${largestNesting} levels the emitter carries`, context.path)
+    return failure('unsupported-nesting-depth', `the marks nest deeper than the ${largestNesting} levels the emitter carries`, context.path)
   }
   const runs = inlineRuns(nodes, depth, firstIndex, context.carried)
   const segments: InlineSegment[] = []