fix: Require newline in all cases for props on block sequence (fixes #557)

Author: eemeli

src/compose/compose-collection.ts

@@ -43,19 +43,40 @@ function resolveCollection(
   return coll
 }
 
+interface Props {
+  anchor: SourceToken | null
+  tag: SourceToken | null
+  newlineAfterProp: SourceToken | null
+}
+
 export function composeCollection(
   CN: ComposeNode,
   ctx: ComposeContext,
   token: BlockMap | BlockSequence | FlowCollection,
-  tagToken: SourceToken | null,
+  props: Props,
   onError: ComposeErrorHandler
 ) {
+  const tagToken = props.tag
   const tagName: string | null = !tagToken
     ? null
     : ctx.directives.tagName(tagToken.source, msg =>
         onError(tagToken, 'TAG_RESOLVE_FAILED', msg)
       )
 
+  if (token.type === 'block-seq') {
+    const { anchor, newlineAfterProp: nl } = props
+    const lastProp =
+      anchor && tagToken
+        ? anchor.offset > tagToken.offset
+          ? anchor
+          : tagToken
+        : anchor ?? tagToken
+    if (lastProp && (!nl || nl.offset < lastProp.offset)) {
+      const message = 'Missing newline after block sequence props'
+      onError(lastProp, 'MISSING_CHAR', message)
+    }
+  }
+
   const expType: 'map' | 'seq' =
     token.type === 'block-map'
       ? 'map'
@@ -72,8 +93,7 @@ export function composeCollection(
     !tagName ||
     tagName === '!' ||
     (tagName === YAMLMap.tagName && expType === 'map') ||
-    (tagName === YAMLSeq.tagName && expType === 'seq') ||
-    !expType
+    (tagName === YAMLSeq.tagName && expType === 'seq')
   ) {
     return resolveCollection(CN, ctx, token, onError, tagName)
   }

src/compose/compose-node.ts

@@ -22,6 +22,7 @@ interface Props {
   comment: string
   anchor: SourceToken | null
   tag: SourceToken | null
+  newlineAfterProp: SourceToken | null
   end: number
 }
 
@@ -57,7 +58,7 @@ export function composeNode(
     case 'block-map':
     case 'block-seq':
     case 'flow-collection':
-      node = composeCollection(CN, ctx, token, tag, onError)
+      node = composeCollection(CN, ctx, token, props, onError)
       if (anchor) node.anchor = anchor.source.substring(1)
       break
     default: {

src/compose/resolve-block-map.ts

@@ -57,7 +57,7 @@ export function resolveBlockMap(
         }
         continue
       }
-      if (keyProps.hasNewlineAfterProp || containsNewline(key)) {
+      if (keyProps.newlineAfterProp || containsNewline(key)) {
         onError(
           key ?? start[start.length - 1],
           'MULTILINE_IMPLICIT_KEY',

src/compose/resolve-props.ts

@@ -29,11 +29,11 @@ export function resolveProps(
   let comment = ''
   let commentSep = ''
   let hasNewline = false
-  let hasNewlineAfterProp = false
   let reqSpace = false
   let tab: SourceToken | null = null
   let anchor: SourceToken | null = null
   let tag: SourceToken | null = null
+  let newlineAfterProp: SourceToken | null = null
   let comma: SourceToken | null = null
   let found: SourceToken | null = null
   let start: number | null = null
@@ -92,7 +92,7 @@ export function resolveProps(
         } else commentSep += token.source
         atNewline = true
         hasNewline = true
-        if (anchor || tag) hasNewlineAfterProp = true
+        if (anchor || tag) newlineAfterProp = token
         hasSpace = true
         break
       case 'anchor':
@@ -189,9 +189,9 @@ export function resolveProps(
     spaceBefore,
     comment,
     hasNewline,
-    hasNewlineAfterProp,
     anchor,
     tag,
+    newlineAfterProp,
     end,
     start: start ?? end
   }

tests/doc/errors.ts

@@ -378,6 +378,31 @@ describe('tags on invalid nodes', () => {
   })
 })
 
+describe('properties on block sequences without newline after props', () => {
+  test('valid properties with newline', () => {
+    const doc = YAML.parseDocument('! &a\n- b')
+    expect(doc.errors).toMatchObject([])
+  })
+
+  test('properties on sequence without newline', () => {
+    const doc = YAML.parseDocument('!\n&a - b')
+    expect(doc.errors).toMatchObject([
+      { code: 'MISSING_CHAR' },
+      { code: 'UNEXPECTED_TOKEN' }
+    ])
+  })
+
+  test('properties on empty sequence without newline', () => {
+    const doc = YAML.parseDocument('&a\n! -')
+    expect(doc.errors).toMatchObject([{ code: 'MISSING_CHAR' }])
+  })
+
+  test('properties on sequence with newline after item indicator', () => {
+    const doc = YAML.parseDocument('!\n&a -\n b')
+    expect(doc.errors).toMatchObject([{ code: 'MISSING_CHAR' }])
+  })
+})
+
 describe('invalid options', () => {
   test('unknown schema', () => {
     expect(() => new YAML.Document(undefined, { schema: 'foo' })).toThrow(