Test for guid collision

Author: jwittner

README.md

@@ -95,6 +95,7 @@ Test-UnityProjectInstanceMetaFileIntegrity .\MyUnityProject -PassThru
 # C:\MyUnityProject\Assets\SomeFolder                               Directory is missing associated meta file.
 # C:\MyUnityProject\Assets\SomeFolder\SomeShader.shader             File is missing associated meta file.
 # C:\MyUnityProject\Assets\SomeFolder\SomeOtherShader.shader.meta   Meta file is missing associated item.
+# C:\MyUnityProject\Assets\SomeFolder\SomeNewShader.shader.meta     Meta file guid collision with C:\MyUnityProject\Assets\SomeFolder\SomeOtherShader.shader.meta
 ```
 
 Find the installers for a particular version:

UnitySetup/UnitySetup.psm1

@@ -1336,7 +1336,9 @@ function Get-UnityProjectInstance {
 .Synopsis
    Tests the meta file integrity of the Unity Project Instance(s).
 .DESCRIPTION
-   Tests if every item under assets has an associated .meta file and every .meta file an associated item.
+   Tests if every item under assets has an associated .meta file 
+   and every .meta file an associated item
+   and that none of the meta file guids collide.
 .PARAMETER Project
    Unity Project Instance(s) to test the meta file integrity of.
 .PARAMETER PassThru
@@ -1458,6 +1460,29 @@ function Test-UnityProjectInstanceMetaFileIntegrity {
                 }
             }
 
+            if (-not $testResult) { $false; continue; }
+
+            Write-Verbose "Testing meta files for guid collisions..."
+            $metaGuids = @{ }
+            foreach ($metaFile in $metaFiles) {
+                $metaContent = Get-Content $metaFile.FullName -Raw | ConvertFrom-Yaml
+                if ($null -eq $metaGuids[$metaContent.guid]) {
+                    $metaGuids[$metaContent.guid] = $metaFile;
+                    continue 
+                }
+
+                if ($PassThru) {
+                    [PSCustomObject]@{
+                        'Item'  = $metaFile
+                        'Issue' = "Meta file guid collision with $($metaGuids[$metaContent.guid])"
+                    }
+                }
+                else {
+                    $testResult = $false;
+                    break;
+                }
+            }
+
             if (-not $PassThru) { $testResult; }
         }
     }