Refactored directory check function

export-windows.ps1

@@ -17,6 +17,26 @@ function Require-Environment([string]$Name) {
     return $value
 }
 
+function Test-PathIsWithinDirectory([string]$ParentDirectory, [string]$CandidateDirectory) {
+    # [IO.Path]::GetRelativePath is not available in Windows PowerShell 5.1.
+    # Compare complete paths with a separator boundary so, for example,
+    # C:\workspace-other is not considered a child of C:\workspace.
+    $parentPath = [IO.Path]::GetFullPath($ParentDirectory)
+    $candidatePath = [IO.Path]::GetFullPath($CandidateDirectory)
+    $directorySeparator = [IO.Path]::DirectorySeparatorChar.ToString()
+    $alternateSeparator = [IO.Path]::AltDirectorySeparatorChar.ToString()
+
+    if ($candidatePath.Equals($parentPath, [StringComparison]::OrdinalIgnoreCase)) {
+        return $true
+    }
+
+    if (-not $parentPath.EndsWith($directorySeparator) -and -not $parentPath.EndsWith($alternateSeparator)) {
+        $parentPath += $directorySeparator
+    }
+
+    return $candidatePath.StartsWith($parentPath, [StringComparison]::OrdinalIgnoreCase)
+}
+
 function Get-ActualArchitecture {
     $architecture = $env:PROCESSOR_ARCHITEW6432
     if ([string]::IsNullOrWhiteSpace($architecture)) {
@@ -98,8 +118,7 @@ if ($HostArch -ne (Get-ActualArchitecture)) { Fail "host-arch '$HostArch' does n
 $workspaceDirectory = [IO.Path]::GetFullPath($Workspace)
 if ([IO.Path]::IsPathRooted($ProjectPath)) { Fail 'project-path must be relative to the checked-out workspace.' }
 $ProjectDirectory = [IO.Path]::GetFullPath((Join-Path $workspaceDirectory $ProjectPath))
-$projectRelativePath = [IO.Path]::GetRelativePath($workspaceDirectory, $ProjectDirectory)
-if ($projectRelativePath -eq '..' -or $projectRelativePath.StartsWith("..$([IO.Path]::DirectorySeparatorChar)") -or [IO.Path]::IsPathRooted($projectRelativePath)) { Fail 'project-path must remain inside the checked-out workspace.' }
+if (-not (Test-PathIsWithinDirectory $workspaceDirectory $ProjectDirectory)) { Fail 'project-path must remain inside the checked-out workspace.' }
 if (-not (Test-Path -LiteralPath (Join-Path $ProjectDirectory 'project.godot') -PathType Leaf)) { Fail "No project.godot was found in project-path '$ProjectPath'." }
 $PresetFile = Join-Path $ProjectDirectory 'export_presets.cfg'
 if (-not (Test-Path -LiteralPath $PresetFile -PathType Leaf)) { Fail "No export_presets.cfg was found in project-path '$ProjectPath'." }