Fix comments

get-new-tool-versions/get-new-tool-versions.ps1

@@ -37,25 +37,23 @@ Write-Host "Get the packages list from $ManifestLink"
 
 [Version[]] $formattedVersions = Format-Versions -Versions $versionsFromDist
 
-if (-not ([string]::IsNullOrEmpty($VersionFilterToInclude))) {
+if ($VersionFilterToInclude) {
     $formattedVersions = Filter-Versions -Versions $formattedVersions `
                                          -VersionFilter $VersionFilterToInclude `
                                          -IncludeVersions $true
 }
 
-if (-not ([string]::IsNullOrEmpty($VersionFilterToExclude))) {
+if ($VersionFilterToExclude) {
     $formattedVersions = Filter-Versions -Versions $formattedVersions `
                                          -VersionFilter $VersionFilterToExclude `
                                          -IncludeVersions $false
 }
 
-$versionsToBuild = Get-VersionsToBuild -VersionsFromManifest $versionsFromManifest `
+$versionsToBuild = Skip-ExistingVersions -VersionsFromManifest $versionsFromManifest `
                                          -VersionsFromDist $formattedVersions
 
-if ([string]::IsNullOrEmpty($versionsToBuild)) {
+if ($versionsToBuild) {
-    Write-Host "There isn't versions to build"
-    return $null
-} else {
     Write-Host "The following versions are available to build:`n$versionsToBuild"
-    return "$versionsToBuild"
+} else {
+    Write-Host "There isn't versions to build"
 }

get-new-tool-versions/helpers.psm1

@@ -8,16 +8,15 @@ function Format-Versions {
     foreach($version in $Versions) { 
         $substredVersion = $null
         
-        # We cut a string from index of first digit because initially it has invalid format (v14.4.0 or go1.14.4)
+        # Cut a string from index of first digit because initially it has invalid format (v14.4.0 or go1.14.4)
-        if ($version -match '(?<number>\d)') {
+        if (-not ($version -match '(?<number>\d)')) {
-            $firstDigitIndex = $version.indexof($Matches.number)
-            $substredVersion = $version.substring($firstDigitIndex)
-        } else {
             Write-Host "Invalid version format - $version"
             exit 1  
         }
+        $firstDigitIndex = $version.indexof($Matches.number)
+        $substredVersion = $version.substring($firstDigitIndex)
         
-        # We filter versions to exclude unstable (for example: "go1.15beta1")
+        # Filter versions to exclude unstable (for example: "go1.15beta1")
         # Valid version format: x.x or x.x.x
         if ($substredVersion -notmatch '^\d+\.+\d+\.*\d*$') {
             continue
@@ -54,14 +53,14 @@ function Filter-Versions {
     return $filteredVersions
 }
 
-function Get-VersionsToBuild {
+function Skip-ExistingVersions {
     param (
         [Parameter(Mandatory)] [string[]] $VersionsFromManifest,
         [Parameter(Mandatory)] [string[]] $VersionsFromDist
     )
 
-    [System.Collections.ArrayList]$versionsToBuid = $VersionsFromDist
+    $newVersions = @()
-    $VersionsFromManifest | ForEach-Object { $versionsToBuid.Remove($_) }
+    $newVersions += $VersionsFromDist | Where-Object { $VersionsFromManifest -notcontains $_ }
 
-    return $versionsToBuid
+    return $newVersions
 }