slightly simpler approach

Author: edyoung

src/PowerShellGet/private/functions/Validate-ModuleCommandAlreadyAvailable.ps1

@@ -50,13 +50,14 @@ function Validate-ModuleCommandAlreadyAvailable
             # To avoid that, appending '*' at the end for each name then comparing the results.
             $CommandNames = $CurrentModuleInfo.ExportedCommands.Values.Name
 
-            # construct a regex matching any of the commands in this module.
-            $Matcher = [regex](($CommandNames | % { "($_)" }) -join "|")
+            # construct a hash with all of the commands in this module.
+            $CommandNameHash = @{}
+            $CommandNames | % { $CommandNameHash[$_] = 1 }
 
             $AvailableCommands = Microsoft.PowerShell.Core\Get-Command -Name *  `
                                                                       -ErrorAction Ignore `
                                                                       -WarningAction SilentlyContinue |
-                                    Microsoft.PowerShell.Core\Where-Object { ($Matcher.IsMatch($_.Name)) -and
+                                    Microsoft.PowerShell.Core\Where-Object { ($CommandNameHash.ContainsKey($_.Name)) -and
                                                                              ($_.ModuleName -ne $script:PSModuleProviderName) -and
                                                                              ($_.ModuleName -ne 'PSModule') -and
                                                                              ($_.ModuleName -ne $CurrentModuleInfo.Name) }