fix: FileDownload cross-platform support and target-path handling

PSDepend/PSDependScripts/FileDownload.ps1

@@ -19,7 +19,7 @@
         Install: Install the dependency
 
     .EXAMPLE
         sqllite_dll = @{
             DependencyType = 'FileDownload'
             Source = 'https://github.com/RamblingCookieMonster/PSSQLite/blob/main/PSSQLite/x64/System.Data.SQLite.dll?raw=true'
             Target = 'C:\temp'
@@ -35,10 +35,10 @@
 
         # Downloads System.Data.SQLite.dll to C:\temp\sqlite.dll
 #>
 [cmdletbinding()]
 param(
     [PSTypeName('PSDepend.Dependency')]
     [psobject[]]
     $Dependency,
 
     [ValidateSet('Test', 'Install')]
@@ -46,7 +46,7 @@
 )
 
 function Parse-URLForFile {
     [cmdletbinding()]
     param($URL)
     # This will need work.  Assume leaf is file.  If CGI exists in leaf, assume it is after the file
     $FileName = $URL.split('/')[-1]
@@ -77,10 +77,13 @@
 # Act on target path....
 $ToInstall = $False # Anti pattern
 
-# Normalize relative paths against $PWD so callers don't get burned by cwd-dependent splits
-if (-not [IO.Path]::IsPathRooted($Target)) {
-    $Target = Join-Path $PWD $Target
-}
+# Capture trailing-separator intent before GetUnresolvedProviderPathFromPSPath normalizes it away;
+# a trailing separator is an explicit signal that the target is a container, not a file.
+$endsWithSeparator = $Target -and
+    $Target[-1] -in @([IO.Path]::DirectorySeparatorChar, [IO.Path]::AltDirectorySeparatorChar)
+
+# Resolve PSDrive paths (e.g. TestDrive:) and relative paths to absolute filesystem paths
+$Target = $PSCmdlet.GetUnresolvedProviderPathFromPSPath($Target)
 
 $TargetParent = Split-Path $Target -Parent
 $PathToAdd = $Target
@@ -94,24 +97,31 @@
     }
     $PathToAdd = Split-Path $Target -Parent
 }
-elseif ([IO.Path]::GetExtension($Target) -and -not (Test-Path $Target -PathType Container)) {
-    # Target has a file extension — treat as a full destination file path
+elseif (
+    -not $endsWithSeparator -and
+    -not (Test-Path $Target -PathType Container) -and
+    ([IO.Path]::GetExtension($Target) -or (Test-Path $TargetParent))
+) {
+    # Treat as a full destination file path.
+    # Triggered when: has a file extension, OR parent already exists and caller gave no trailing separator.
+    # The trailing-separator check preserves extensionless binary targets (e.g. /usr/local/bin/terraform)
+    # while still allowing directory-like targets to be signalled with a trailing slash.
+    $PathToAdd = $TargetParent
     if (-not (Test-Path $TargetParent)) {
         Write-Error "Could not find parent path [$TargetParent] for target [$Target]"
         if ($PSDependAction -contains 'Test') {
             return $False
         }
+        return
     }
-    else {
-        $Path = $Target
-        $ToInstall = $True
-        Write-Verbose "Target has extension, treating as file path [$Target]"
-    }
+    $Path = $Target
+    $ToInstall = $True
+    Write-Verbose "Treating as destination file path [$Target]"
 }
 else {
-    # No extension (or already a container) — treat target as a directory
+    # No extension (or already a container, or explicit trailing separator) — treat target as a directory
     Write-Verbose "[$Target] is a container, creating path to file"
-    if (-not (Test-Path $Target)) {
+    if (-not (Test-Path $Target) -and $PSDependAction -contains 'Install') {
         New-Item -ItemType Directory -Path $Target -Force | Out-Null
     }
     If ($Name) {

Tests/FileDownload.Type.Tests.ps1

@@ -73,13 +73,15 @@
     }
 
     It 'Creates a new directory and downloads into it when Target has no extension and does not exist' {
-        $newDir = Join-Path (New-Item 'TestDrive:/dl5base' -ItemType Directory -Force).FullName 'newcontainer'
-        $dep = New-PSDependFixture -DependencyName 'https://example.com/sample.dll' -DependencyType 'FileDownload' -Target $newDir
+        $base = (New-Item 'TestDrive:/dl5base' -ItemType Directory -Force).FullName
+        $newDir = Join-Path $base 'newcontainer'
+        # Trailing separator signals "this is a container, not an extensionless file"
+        $dep = New-PSDependFixture -DependencyName 'https://example.com/sample.dll' -DependencyType 'FileDownload' -Target "$newDir/"
         InModuleScope PSDepend -Parameters @{ Dep = $dep; ScriptPath = $script:ScriptPath; T = $newDir } {
             & $ScriptPath -Dependency $Dep
         }
         Should -Invoke -CommandName Get-WebFile -ModuleName PSDepend -Times 1 -Exactly -ParameterFilter {
             $URL -eq 'https://example.com/sample.dll' -and ($Path -like "*newcontainer*sample.dll")
         }
         Test-Path $newDir -PathType Container | Should -Be $true
     }
@@ -97,10 +99,11 @@
     }
 
     It 'Roots a relative Target against $PWD and downloads to it' {
         $baseDir = (New-Item 'TestDrive:/relbase' -ItemType Directory -Force).FullName
         Push-Location $baseDir
         try {
-            $dep = New-PSDependFixture -DependencyName 'https://example.com/sample.dll' -DependencyType 'FileDownload' -Target 'subdir'
+            # Trailing separator signals "this is a container, not an extensionless file"
+            $dep = New-PSDependFixture -DependencyName 'https://example.com/sample.dll' -DependencyType 'FileDownload' -Target 'subdir/'
             InModuleScope PSDepend -Parameters @{ Dep = $dep; ScriptPath = $script:ScriptPath } {
                 & $ScriptPath -Dependency $Dep
             }