Validate keys after YAML removal

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: MariusStorhaug

src/functions/private/Assert-YamlRemovalGraph.ps1

@@ -143,6 +143,7 @@ function Assert-YamlRemovalGraph {
                         ))
                 }
             }
+
         }
         for ($index = $node.Entries.Count - 1; $index -ge 0; $index--) {
             $pending.Push([pscustomobject]@{
@@ -155,4 +156,21 @@ function Assert-YamlRemovalGraph {
                 })
         }
     }
+
+    $fingerprintCache = [System.Collections.Generic.Dictionary[int, string]]::new()
+    $fingerprintHasher = [System.Security.Cryptography.SHA256]::Create()
+    $fingerprintWorkState = [pscustomobject]@{
+        Count    = 0L
+        MaxNodes = $MaxNodes
+    }
+    try {
+        foreach ($document in $Documents) {
+            Test-YamlNodeGraph -Node $document `
+                -Visited ([System.Collections.Generic.HashSet[int]]::new()) `
+                -FingerprintCache $fingerprintCache -FingerprintHasher $fingerprintHasher `
+                -RemovalWorkState $fingerprintWorkState
+        }
+    } finally {
+        $fingerprintHasher.Dispose()
+    }
 }

src/functions/private/Get-YamlNodeFingerprint.ps1

@@ -18,7 +18,11 @@ function Get-YamlNodeFingerprint {
         [System.Collections.Generic.Dictionary[int, string]] $Cache,
 
         [Parameter(Mandatory)]
-        [System.Security.Cryptography.HashAlgorithm] $Hasher
+        [System.Security.Cryptography.HashAlgorithm] $Hasher,
+
+        [Parameter()]
+        [AllowNull()]
+        [pscustomobject] $RemovalWorkState
     )
 
     $root = [pscustomobject]@{ Value = '' }
@@ -48,6 +52,10 @@ function Get-YamlNodeFingerprint {
                 [void] $stack.Pop()
                 continue
             }
+            if ($null -ne $RemovalWorkState) {
+                Add-YamlRemovalWork -State $RemovalWorkState `
+                    -Operation 'duplicate-key fingerprint' -Node $effective
+            }
             if (-not $Active.Add($effective.Id)) {
                 throw (New-YamlException -Start $effective.Start -End $effective.End `
                         -ErrorId 'YamlCyclicMappingKey' -Message (

src/functions/private/Test-YamlNodeGraph.ps1

@@ -17,7 +17,11 @@ function Test-YamlNodeGraph {
         [System.Collections.Generic.Dictionary[int, string]] $FingerprintCache,
 
         [Parameter(Mandatory)]
-        [System.Security.Cryptography.HashAlgorithm] $FingerprintHasher
+        [System.Security.Cryptography.HashAlgorithm] $FingerprintHasher,
+
+        [Parameter()]
+        [AllowNull()]
+        [pscustomobject] $RemovalWorkState
     )
 
     $scalarTags = [System.Collections.Generic.HashSet[string]]::new(
@@ -94,7 +98,8 @@ function Test-YamlNodeGraph {
                         $keyFingerprint = Get-YamlNodeFingerprint `
                             -Node $entryNode.Entries[0].Key `
                             -Active ([System.Collections.Generic.HashSet[int]]::new()) `
-                            -Cache $FingerprintCache -Hasher $FingerprintHasher
+                            -Cache $FingerprintCache -Hasher $FingerprintHasher `
+                            -RemovalWorkState $RemovalWorkState
                         if (-not $orderedKeys.Add($keyFingerprint)) {
                             $keyNode = $entryNode.Entries[0].Key
                             throw (New-YamlException -Start $keyNode.Start -End $keyNode.End `
@@ -127,7 +132,8 @@ function Test-YamlNodeGraph {
             $entry = $current.Entries[$index]
             $fingerprint = Get-YamlNodeFingerprint -Node $entry.Key `
                 -Active ([System.Collections.Generic.HashSet[int]]::new()) `
-                -Cache $FingerprintCache -Hasher $FingerprintHasher
+                -Cache $FingerprintCache -Hasher $FingerprintHasher `
+                -RemovalWorkState $RemovalWorkState
             if (-not $keys.Add($fingerprint)) {
                 throw (New-YamlException -Start $entry.Key.Start -End $entry.Key.End `
                         -ErrorId 'YamlDuplicateKey' -Message (

tests/Remove-YamlEntry.Tests.ps1

@@ -613,6 +613,46 @@ root: !item
             $failure.Exception.Data['YamlErrorId'] |
                 Should -BeExactly 'YamlInvalidTaggedCollection'
         }
+
+        It 'rejects post-removal duplicate representation keys' -ForEach @(
+            @{
+                Yaml = @'
+cycle: &cycle { self: *cycle }
+shared: &shared { x: 1, y: 2 }
+? *shared
+: first
+? { x: 1 }
+: second
+'@
+            }
+            @{
+                Yaml = @'
+shared: &shared { x: 1, y: 2 }
+set: !!set
+  ? *shared
+  ? { x: 1 }
+'@
+            }
+            @{
+                Yaml = @'
+shared: &shared { x: 1, y: 2 }
+ordered: !!omap
+  - ? *shared
+    : first
+  - ? { x: 1 }
+    : second
+'@
+            }
+        ) {
+            $failure = Get-RemoveYamlFailure {
+                Remove-YamlEntry $Yaml '/shared/y'
+            }
+
+            $failure.Exception.Data['YamlErrorId'] |
+                Should -BeExactly 'YamlDuplicateKey'
+            $failure.FullyQualifiedErrorId |
+                Should -Be 'YamlDuplicateKey,Remove-YamlEntry'
+        }
     }
 
     Context 'Validation and work limits' {