Improved requires on invalid null/empty arguments

Invoke-Build.ps1

@@ -318,20 +318,30 @@ function Remove-BuildItem([Parameter(Mandatory=1)][string[]]$Path) {
 }
 
 #.ExternalHelp Help.xml
-function Test-BuildAsset([Parameter(Position=0)][string[]]$Variable, [string[]]$Environment, [string[]]$Path, [string[]]$Property) {
-	Remove-Variable Variable, Environment, Path, Property
-	if ($_ = $PSBoundParameters['Variable']) {foreach($_ in $_) {
+function Test-BuildAsset(
+	[ValidateNotNull()][string[]][Parameter(Position=0)]$Variable,
+	[ValidateNotNull()][string[]]$Environment,
+	[ValidateNotNull()][string[]]$Property,
+	[ValidateNotNull()][string[]]$Path
+) {
+	Remove-Variable Variable, Environment, Property, Path
+	function *get($p, $n) {
+		if ($_ = $p[$n]) {
+			$_ | .{process{if ($_) {$_} else {*Die "Invalid empty '$n'."}}}
+		}
+	}
+	foreach($_ in *get $PSBoundParameters Variable) {
 		if ($null -eq ($$ = $PSCmdlet.GetVariableValue($_)) -or '' -eq $$) {*Die "Missing variable '$_'." 13}
-	}}
-	if ($_ = $PSBoundParameters['Environment']) {foreach($_ in $_) {
+	}
+	foreach($_ in *get $PSBoundParameters Environment) {
 		if (!([Environment]::GetEnvironmentVariable($_))) {*Die "Missing environment variable '$_'." 13}
-	}}
-	if ($_ = $PSBoundParameters['Property']) {foreach($_ in $_) {
+	}
+	foreach($_ in *get $PSBoundParameters Property) {
 		if ('' -eq (Get-BuildProperty $_ '')) {*Die "Missing property '$_'." 13}
-	}}
-	if ($_ = $PSBoundParameters['Path']) {foreach($_ in $_) {
+	}
+	foreach($_ in *get $PSBoundParameters Path) {
 		if (!(Test-Path -LiteralPath $_)) {*Die "Missing path '$_'." 13}
-	}}
+	}
 }
 
 #.ExternalHelp Help.xml

Release-Notes.md

@@ -1,5 +1,10 @@
 # Invoke-Build Release Notes
 
+## v5.11.1
+
+`requires` / `Test-BuildAsset`
+- improved errors on invalid null/empty arguments
+
 ## v5.11.0
 
 `exec` / `Invoke-BuildExec`

Tests/Requires.test.ps1

@@ -91,3 +91,31 @@ task PropertyEnvironment {
 
 	$env:miss1 = $null
 }
+
+task NullArgument1 {
+	try { throw requires -Variable $null }
+	catch { assert ($_ -like '*The argument is null.*') }
+
+	try { throw requires -Environment $null }
+	catch { assert ($_ -like '*The argument is null.*') }
+
+	try { throw requires -Property $null }
+	catch { assert ($_ -like '*The argument is null.*') }
+
+	try { throw requires -Path $null }
+	catch { assert ($_ -like '*The argument is null.*') }
+}
+
+task NullArgument2 {
+	try { throw requires -Variable host, $null }
+	catch { assert ("Invalid empty 'Variable'." -eq $_) }
+
+	try { throw requires -Environment path, $null }
+	catch { assert ("Invalid empty 'Environment'." -eq $_) }
+
+	try { throw requires -Property host, $null }
+	catch { assert ("Invalid empty 'Property'." -eq $_) }
+
+	try { throw requires -Path ., $null }
+	catch { assert ("Invalid empty 'Path'." -eq $_) }
+}