Refactor PowerShell installation logic to improve version comparison and uninstallation process across platforms

Author: MariusStorhaug

action.yml

@@ -19,17 +19,6 @@ runs:
       run: |
         $version = '${{ inputs.version }}'
 
-        # Try to remove existing PowerShell installation
-        try {
-          # Find existing PowerShell installations to remove
-          Get-Package -Name "PowerShell*" -ErrorAction SilentlyContinue | ForEach-Object {
-            Write-Host "Uninstalling $($_.Name) version $($_.Version)"
-            Uninstall-Package -Name $_.Name -Force -ErrorAction SilentlyContinue
-          }
-        } catch {
-          Write-Host "Error removing existing PowerShell: $_"
-        }
-
         # Get the version to install
         if ([string]::IsNullOrWhiteSpace($version)) {
           # Get latest version from GitHub API
@@ -40,6 +29,47 @@ runs:
           Write-Host "Installing specified PowerShell version: $version"
         }
 
+        # Check existing PowerShell installation
+        $shouldUninstall = $false
+        try {
+          $existingPowerShell = Get-Package -Name "PowerShell*" -ErrorAction SilentlyContinue
+          if ($existingPowerShell) {
+            # Convert versions to System.Version objects for proper comparison
+            $targetVersion = [System.Version]::new($version)
+            foreach ($installation in $existingPowerShell) {
+              $installedVersionStr = $installation.Version
+              $installedVersion = [System.Version]::new($installedVersionStr)
+              
+              Write-Host "Found existing PowerShell: $($installation.Name) version $installedVersionStr"
+              
+              # Only uninstall if target version is lower than installed version
+              if ($targetVersion -lt $installedVersion) {
+                Write-Host "Target version $version is lower than installed version $installedVersionStr. Will uninstall."
+                $shouldUninstall = $true
+                break
+              } else {
+                Write-Host "Target version $version is equal to or higher than installed version $installedVersionStr. No need to uninstall."
+              }
+            }
+          } else {
+            Write-Host "No existing PowerShell installation found."
+          }
+        } catch {
+          Write-Host "Error checking existing PowerShell: $_"
+        }
+
+        # Remove existing PowerShell installation if needed
+        if ($shouldUninstall) {
+          try {
+            Get-Package -Name "PowerShell*" -ErrorAction SilentlyContinue | ForEach-Object {
+              Write-Host "Uninstalling $($_.Name) version $($_.Version)"
+              Uninstall-Package -Name $_.Name -Force -ErrorAction SilentlyContinue
+            }
+          } catch {
+            Write-Host "Error removing existing PowerShell: $_"
+          }
+        }
+
         # Download and install PowerShell
         $msiName = "PowerShell-$version-win-x64.msi"
         $downloadUrl = "https://github.com/PowerShell/PowerShell/releases/download/v$version/$msiName"
@@ -64,15 +94,42 @@ runs:
       if: runner.os == 'Linux'
       shell: bash
       run: |
-        sudo apt-get remove powershell -y
         version='${{ inputs.version }}'
         if [ -z "$version" ]; then
+          # Get latest version if not specified
           version=$(curl -s https://api.github.com/repos/PowerShell/PowerShell/releases/latest | grep 'tag_name' | cut -d '"' -f 4)
+          echo "Latest PowerShell version: $version"
         else
           version="v$version"
+          echo "Installing specified PowerShell version: $version"
         fi
-        wget https://github.com/PowerShell/PowerShell/releases/download/$version/powershell_${version#v}-1.deb_amd64.deb
-        sudo dpkg -i powershell_${version#v}-1.deb_amd64.deb
+        
+        # Clean version without v prefix
+        clean_version=${version#v}
+        
+        # Check if PowerShell is already installed
+        if command -v pwsh &> /dev/null; then
+          installed_version=$(pwsh -NoProfile -Command '$PSVersionTable.PSVersion.ToString()' | tr -d '\r\n')
+          echo "Found existing PowerShell version: $installed_version"
+          
+          # Compare versions
+          target_version=$clean_version
+          
+          # Only uninstall if target version is lower than installed version
+          if [ "$(printf '%s\n' "$target_version" "$installed_version" | sort -V | head -n1)" = "$target_version" ] && 
+             [ "$target_version" != "$installed_version" ]; then
+            echo "Target version $clean_version is lower than installed version $installed_version. Will uninstall."
+            sudo apt-get remove powershell -y
+          else
+            echo "Target version $clean_version is equal to or higher than installed version $installed_version. No need to uninstall."
+          fi
+        else
+          echo "No existing PowerShell installation found."
+        fi
+        
+        # Download and install PowerShell
+        wget https://github.com/PowerShell/PowerShell/releases/download/$version/powershell_${clean_version}-1.deb_amd64.deb
+        sudo dpkg -i powershell_${clean_version}-1.deb_amd64.deb
         sudo apt-get install -f
 
     - name: Install PowerShell on macOS