search: guard empty latest-row input

Author: B67687

lib/database.ps1

@@ -4,13 +4,24 @@ if (-not (Get-Command Compare-Version -ErrorAction Ignore)) {
     . "$PSScriptRoot\versions.ps1"
 }
 
+<#
+.SYNOPSIS
+    Get the latest row from a set of Scoop database rows.
+.DESCRIPTION
+    Compares the `version` property of each row semantically and returns the
+    latest row. Returns `$null` when no rows are provided.
+#>
 function Get-LatestScoopDBRow {
     param(
         [Parameter(Mandatory)]
         [object[]]
         $Rows
     )
 
+    if (-not $Rows -or $Rows.Count -eq 0) {
+        return $null
+    }
+
     $latest = $Rows[0]
     foreach ($row in ($Rows | Select-Object -Skip 1)) {
         if ((Compare-Version -ReferenceVersion $latest.version -DifferenceVersion $row.version) -gt 0) {

test/Scoop-Database.Tests.ps1

@@ -15,6 +15,10 @@ Describe 'database version selection' -Tag 'Scoop' {
         (Get-LatestScoopDBRow -Rows $rows).version | Should -Be '1.0.31'
     }
 
+    It 'returns null when no rows are provided' {
+        Get-LatestScoopDBRow -Rows @() | Should -Be $null
+    }
+
     It 'returns the latest semantic version per name and bucket' {
         $result = New-Object System.Data.DataTable
         [void]$result.Columns.Add('name', [string])