From 5096f837863a63abda5fb0204e251ba286d11acc Mon Sep 17 00:00:00 2001
From: Eemeli Aro <eemeli@gmail.com>
Date: Sat, 8 Jun 2024 16:31:37 +0300
Subject: [PATCH] fix: Require indentation for ? explicit-key contents (fixes
 #551)

Adds `explicitKey?: true` to CST BlockMap items
---
 src/parse/cst.ts    |  9 ++++++++-
 src/parse/parser.ts | 21 +++++++++------------
 tests/doc/parse.ts  | 15 +++++++++++++++
 3 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/src/parse/cst.ts b/src/parse/cst.ts
index 1d5c97e2..82b66dee 100644
--- a/src/parse/cst.ts
+++ b/src/parse/cst.ts
@@ -81,9 +81,16 @@ export interface BlockMap {
   offset: number
   indent: number
   items: Array<
-    | { start: SourceToken[]; key?: never; sep?: never; value?: never }
     | {
         start: SourceToken[]
+        explicitKey?: true
+        key?: never
+        sep?: never
+        value?: never
+      }
+    | {
+        start: SourceToken[]
+        explicitKey?: true
         key: Token | null
         sep: SourceToken[]
         value?: Token
diff --git a/src/parse/parser.ts b/src/parse/parser.ts
index fb1453b4..af09b527 100644
--- a/src/parse/parser.ts
+++ b/src/parse/parser.ts
@@ -325,7 +325,7 @@ export class Parser {
             it.value = token
           } else {
             Object.assign(it, { key: token, sep: [] })
-            this.onKeyLine = !includesToken(it.start, 'explicit-key-ind')
+            this.onKeyLine = !it.explicitKey
             return
           }
           break
@@ -532,7 +532,7 @@ export class Parser {
       const atNextItem =
         !this.onKeyLine &&
         this.indent === map.indent &&
-        it.sep &&
+        (it.sep || it.explicitKey) &&
         this.type !== 'seq-item-ind'
 
       // For empty nodes, assign newline-separated not indented empty tokens to following node
@@ -572,24 +572,25 @@ export class Parser {
           return
 
         case 'explicit-key-ind':
-          if (!it.sep && !includesToken(it.start, 'explicit-key-ind')) {
+          if (!it.sep && !it.explicitKey) {
             it.start.push(this.sourceToken)
+            it.explicitKey = true
           } else if (atNextItem || it.value) {
             start.push(this.sourceToken)
-            map.items.push({ start })
+            map.items.push({ start, explicitKey: true })
           } else {
             this.stack.push({
               type: 'block-map',
               offset: this.offset,
               indent: this.indent,
-              items: [{ start: [this.sourceToken] }]
+              items: [{ start: [this.sourceToken], explicitKey: true }]
             })
           }
           this.onKeyLine = true
           return
 
         case 'map-value-ind':
-          if (includesToken(it.start, 'explicit-key-ind')) {
+          if (it.explicitKey) {
             if (!it.sep) {
               if (includesToken(it.start, 'newline')) {
                 Object.assign(it, { key: null, sep: [this.sourceToken] })
@@ -672,11 +673,7 @@ export class Parser {
         default: {
           const bv = this.startBlockValue(map)
           if (bv) {
-            if (
-              atNextItem &&
-              bv.type !== 'block-seq' &&
-              includesToken(it.start, 'explicit-key-ind')
-            ) {
+            if (atNextItem && bv.type !== 'block-seq' && it.explicitKey) {
               map.items.push({ start })
             }
             this.stack.push(bv)
@@ -888,7 +885,7 @@ export class Parser {
           type: 'block-map',
           offset: this.offset,
           indent: this.indent,
-          items: [{ start }]
+          items: [{ start, explicitKey: true }]
         } as BlockMap
       }
       case 'map-value-ind': {
diff --git a/tests/doc/parse.ts b/tests/doc/parse.ts
index 1a319325..a6af6764 100644
--- a/tests/doc/parse.ts
+++ b/tests/doc/parse.ts
@@ -409,6 +409,21 @@ describe('maps with no values', () => {
   })
 })
 
+describe('odd indentations', () => {
+  test('Block map with empty explicit key (#551)', () => {
+    const doc = YAML.parseDocument<YAML.YAMLMap, false>('?\n? a')
+    expect(doc.contents.items).toMatchObject([
+      { key: { value: null }, value: null },
+      { key: { value: 'a' }, value: null }
+    ])
+  })
+
+  test('Block map with unindented !!null explicit key', () => {
+    const doc = YAML.parseDocument<YAML.YAMLMap, false>('?\n!!null')
+    expect(doc.errors).not.toHaveLength(0)
+  })
+})
+
 describe('Excessive entity expansion attacks', () => {
   const root = resolve(__dirname, '../artifacts/pr104')
   const src1 = readFileSync(resolve(root, 'case1.yml'), 'utf8')