🚀 [Feature]: Support installing prerelease PowerShell versions

.github/workflows/Action-Test.yml

@@ -22,7 +22,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
-        version: ['latest', '7.4.7', '7.5.0']
+        version: ['latest', 'prerelease', '7.4.7', '7.5.0', '7.6.0-preview.6']
     runs-on: ${{ matrix.os }}
     name: '${{ matrix.os }} - [${{ matrix.version }}]'
     steps:
@@ -34,7 +34,8 @@ jobs:
       - name: Action-Test
         uses: ./
         with:
-          Version: ${{ matrix.version }}
+          Version: ${{ matrix.version == 'prerelease' && 'latest' || matrix.version }}
+          Prerelease: ${{ matrix.version == 'prerelease' && 'true' || 'false' }}
 
       - name: Verify installed version
         shell: pwsh
@@ -44,8 +45,23 @@ jobs:
           # Requested version that came from the matrix
           $requested = '${{ matrix.version }}'
 
+          # When 'prerelease' → resolve to latest prerelease
+          if ($requested.Trim().ToLower() -eq 'prerelease') {
+              $releases = Invoke-RestMethod -Uri 'https://api.github.com/repos/PowerShell/PowerShell/releases' `
+                -Headers @{
+                  'Accept' = 'application/vnd.github+json'
+                  'Authorization' = "Bearer $($env:GITHUB_TOKEN)"
+                  'X-GitHub-Api-Version' = '2022-11-28'
+                }
+              $latestPrerelease = $releases | Where-Object { $_.prerelease -eq $true } | Select-Object -First 1
+              if (-not $latestPrerelease) {
+                  throw "No prerelease releases found for PowerShell/PowerShell."
+              }
+              $requested = $latestPrerelease.tag_name.TrimStart('v')
+              Write-Host "Resolved 'prerelease' → $requested"
+          }
           # When empty / 'null' / 'latest' → resolve to latest stable release
-          if ([string]::IsNullOrWhiteSpace($requested) -or
+          elseif ([string]::IsNullOrWhiteSpace($requested) -or
               $requested.Trim().ToLower() -in @('latest','null')) {
 
               $requested = (
@@ -59,8 +75,24 @@ jobs:
               Write-Host "Resolved 'latest' → $requested"
           }
 
-          # Actual version installed by the action
-          $installed = ($PSVersionTable.PSVersion).ToString()
+          # On Windows, always verify by launching pwsh from the known install directory.
+          # This avoids relying on PATH resolution, which may still point to the pre-installed
+          # version if the runner's environment hasn't refreshed after the MSI install.
+          if ($IsWindows) {
+              $isPrerelease = $requested -match '-'
+              $majorVersion = ($requested -split '[\.-]')[0]
+              $installDir = if ($isPrerelease) { "$majorVersion-preview" } else { $majorVersion }
+              $pwshPath = "$env:ProgramFiles\PowerShell\$installDir\pwsh.exe"
+              Write-Host "Windows: verifying via subprocess at $pwshPath"
+              if (Test-Path $pwshPath) {
+                  $installed = (& $pwshPath -NoLogo -NoProfile -Command '$PSVersionTable.PSVersion.ToString()')
+              } else {
+                  Write-Host "Warning: Expected pwsh not found at $pwshPath, falling back to `$PSVersionTable"
+                  $installed = ($PSVersionTable.PSVersion).ToString()
+              }
+          } else {
+              $installed = ($PSVersionTable.PSVersion).ToString()
+          }
           Write-Host "Installed PowerShell version: $installed"
           Write-Host "Expected  PowerShell version: $requested"
 

README.md

@@ -2,6 +2,7 @@
 
 A cross‑platform GitHub Action that installs a specific **PowerShell Core** version—or the latest stable release—on any GitHub‑hosted runner
 (Linux, macOS, or Windows). The action automatically skips installation when the requested version is already present.
+Prerelease versions (e.g. `7.6.0-preview.6`, `7.5.0-rc.1`) are also supported.
 
 ## Usage
 
@@ -25,11 +26,30 @@ jobs:
           Write-Host "Using PowerShell $($PSVersionTable.PSVersion)"
 ```
 
+### Installing a prerelease version
+
+```yaml
+      - name: Install PowerShell Preview
+        uses: PSModule/install-powershell@v1
+        with:
+          Version: 7.6.0-preview.6
+```
+
+### Installing the latest prerelease
+
+```yaml
+      - name: Install latest PowerShell Preview
+        uses: PSModule/install-powershell@v1
+        with:
+          Prerelease: true
+```
+
 ## Inputs
 
 | Input | Required | Default | Description |
 | ----- | -------- | ------- | ----------- |
-| `Version` | `false` | `latest` | Desired PowerShell Core version (e.g. `7.4.1`). Use `latest` to install the newest stable release. |
+| `Version` | `false` | `latest` | Desired PowerShell Core version (e.g. `7.4.1`, `7.6.0-preview.6`). Use `latest` to install the newest stable release (or newest prerelease when `Prerelease` is `true`). |
+| `Prerelease` | `false` | `false` | Install a prerelease version. When `true` and `Version` is `latest`, resolves to the latest prerelease. Similar to `-Prerelease` on `Install-PSResource`. |
 
 ## Secrets
 
@@ -43,7 +63,8 @@ This action does **not** generate any outputs.
 
 * **Version resolution**
   If `Version` is set to `latest` (case‑insensitive), the action queries the GitHub API for the newest stable release tag in the
-  `PowerShell/PowerShell` repository and substitutes that version.
+  `PowerShell/PowerShell` repository and substitutes that version. When `Prerelease` is `true`, it queries for the latest prerelease
+  instead. Explicit prerelease version strings (e.g. `7.6.0-preview.6`) are passed through directly.
 
 * **Skip logic**
   Before installing, the action checks the current runner to see whether the requested version is already available

action.yml

@@ -11,10 +11,18 @@ branding:
 inputs:
   Version:
     description: |
-      PowerShell version to install (e.g. `7.4.1`).
+      PowerShell version to install (e.g. `7.4.1` or `7.6.0-preview.6`).
       Defaults to install the latest stable release.
+      Prerelease versions are supported (e.g. `7.6.0-preview.6`, `7.5.0-rc.1`).
     required: false
     default: 'latest'
+  Prerelease:
+    description: |
+      Install a prerelease version of PowerShell.
+      When `true` and `Version` is `latest`, installs the latest prerelease.
+      Similar to the `-Prerelease` switch on `Install-PSResource`.
+    required: false
+    default: 'false'
 
 runs:
   using: composite
@@ -25,24 +33,46 @@ runs:
       working-directory: ${{ github.action_path }}
       env:
         REQUESTED_VERSION: ${{ inputs.Version }}
+        PRERELEASE: ${{ inputs.Prerelease }}
         GITHUB_TOKEN: ${{ github.token }}
-      run: |
+      run: | # zizmor: ignore[github-env] GITHUB_PATH writes use hardcoded install dirs, not user input
         # Install-PowerShell
         set -e
         echo "Requested version: [$REQUESTED_VERSION]"
+        echo "Prerelease: [$PRERELEASE]"
 
         # Only resolve to latest version if explicitly set to 'latest' (case-insensitive)
         case "${REQUESTED_VERSION:-}" in
             [Ll][Aa][Tt][Ee][Ss][Tt])
-                REQUESTED_VERSION=$(
-                  curl -s -f \
-                    -H "Accept: application/vnd.github+json" \
-                    -H "Authorization: Bearer $GITHUB_TOKEN" \
-                    -H "X-GitHub-Api-Version: 2022-11-28" \
-                    https://api.github.com/repos/PowerShell/PowerShell/releases/latest |
-                    jq -r '.tag_name' | sed 's/^v//'
-                )
-                echo "Latest stable PowerShell release detected: $REQUESTED_VERSION"
+                if [[ "$PRERELEASE" == "true" ]]; then
+                    REQUESTED_VERSION=$(
+                      curl -s -f \
+                        -H "Accept: application/vnd.github+json" \
+                        -H "Authorization: Bearer $GITHUB_TOKEN" \
+                        -H "X-GitHub-Api-Version: 2022-11-28" \
+                        https://api.github.com/repos/PowerShell/PowerShell/releases |
+                        jq -r '[.[] | select(.prerelease == true)] | (.[0].tag_name // empty)' | sed 's/^v//'
+                    )
+                    if [[ -z "$REQUESTED_VERSION" ]]; then
+                        echo "Error: No prerelease PowerShell releases found when resolving latest prerelease."
+                        exit 1
+                    fi
+                    echo "Latest prerelease PowerShell version detected: $REQUESTED_VERSION"
+                else
+                    REQUESTED_VERSION=$(
+                      curl -s -f \
+                        -H "Accept: application/vnd.github+json" \
+                        -H "Authorization: Bearer $GITHUB_TOKEN" \
+                        -H "X-GitHub-Api-Version: 2022-11-28" \
+                        https://api.github.com/repos/PowerShell/PowerShell/releases/latest |
+                        jq -r '.tag_name' | sed 's/^v//'
+                    )
+                    if [[ -z "$REQUESTED_VERSION" ]]; then
+                        echo "Error: Failed to resolve latest stable PowerShell release from GitHub."
+                        exit 1
+                    fi
+                    echo "Latest stable PowerShell release detected: $REQUESTED_VERSION"
+                fi
                 ;;
             "")
                 echo "Error: Version input is required (or use 'latest')"
@@ -93,30 +123,63 @@ runs:
         fi
         echo "Installation complete. PowerShell [$REQUESTED_VERSION] is now available."
 
+        # For prerelease builds, add the install directory to GITHUB_PATH so subsequent
+        # `shell: pwsh` steps resolve to the version we just installed.
+        if [[ "$REQUESTED_VERSION" == *-* ]]; then
+          MAJOR_VERSION=$(echo "$REQUESTED_VERSION" | cut -d'.' -f1)
+          INSTALL_DIR="/opt/microsoft/powershell/${MAJOR_VERSION}-preview"
+          if [[ -d "$INSTALL_DIR" ]]; then
+            echo "Adding install directory to GITHUB_PATH: $INSTALL_DIR"
+            echo "$INSTALL_DIR" >> "$GITHUB_PATH"
+          fi
+        fi
+
     - name: Install PowerShell (macOS)
       if: runner.os == 'macOS'
       shell: bash
       working-directory: ${{ github.action_path }}
       env:
         REQUESTED_VERSION: ${{ inputs.Version }}
+        PRERELEASE: ${{ inputs.Prerelease }}
         GITHUB_TOKEN: ${{ github.token }}
-      run: |
+      run: | # zizmor: ignore[github-env] GITHUB_PATH writes use hardcoded install dirs, not user input
         # Install-PowerShell
         set -e
         echo "Requested version: [$REQUESTED_VERSION]"
+        echo "Prerelease: [$PRERELEASE]"
 
         # Only resolve to latest version if explicitly set to 'latest' (case-insensitive)
         case "${REQUESTED_VERSION:-}" in
             [Ll][Aa][Tt][Ee][Ss][Tt])
-                REQUESTED_VERSION=$(
-                  curl -s -f \
-                    -H "Accept: application/vnd.github+json" \
-                    -H "Authorization: Bearer $GITHUB_TOKEN" \
-                    -H "X-GitHub-Api-Version: 2022-11-28" \
-                    https://api.github.com/repos/PowerShell/PowerShell/releases/latest |
-                    jq -r '.tag_name' | sed 's/^v//'
-                )
-                echo "Latest stable PowerShell release detected: $REQUESTED_VERSION"
+                if [[ "$PRERELEASE" == "true" ]]; then
+                    REQUESTED_VERSION=$(
+                      curl -s -f \
+                        -H "Accept: application/vnd.github+json" \
+                        -H "Authorization: Bearer $GITHUB_TOKEN" \
+                        -H "X-GitHub-Api-Version: 2022-11-28" \
+                        https://api.github.com/repos/PowerShell/PowerShell/releases |
+                        jq -r '[.[] | select(.prerelease == true)] | (.[0].tag_name // empty)' | sed 's/^v//'
+                    )
+                    if [[ -z "$REQUESTED_VERSION" ]]; then
+                        echo "Error: No prerelease PowerShell releases found when resolving latest prerelease."
+                        exit 1
+                    fi
+                    echo "Latest prerelease PowerShell version detected: $REQUESTED_VERSION"
+                else
+                    REQUESTED_VERSION=$(
+                      curl -s -f \
+                        -H "Accept: application/vnd.github+json" \
+                        -H "Authorization: Bearer $GITHUB_TOKEN" \
+                        -H "X-GitHub-Api-Version: 2022-11-28" \
+                        https://api.github.com/repos/PowerShell/PowerShell/releases/latest |
+                        jq -r '.tag_name' | sed 's/^v//'
+                    )
+                    if [[ -z "$REQUESTED_VERSION" ]]; then
+                        echo "Error: Failed to resolve latest stable PowerShell release from GitHub."
+                        exit 1
+                    fi
+                    echo "Latest stable PowerShell release detected: $REQUESTED_VERSION"
+                fi
                 ;;
             "")
                 echo "Error: Version input is required (or use 'latest')"
@@ -154,29 +217,55 @@ runs:
         sudo installer -pkg "$PKG_NAME" -target /
         echo "Installation complete. PowerShell [$REQUESTED_VERSION] is now available."
 
+        # For prerelease builds, add the install directory to GITHUB_PATH so subsequent
+        # `shell: pwsh` steps resolve to the version we just installed.
+        if [[ "$REQUESTED_VERSION" == *-* ]]; then
+          MAJOR_VERSION=$(echo "$REQUESTED_VERSION" | cut -d'.' -f1)
+          INSTALL_DIR="/usr/local/microsoft/powershell/${MAJOR_VERSION}-preview"
+          if [[ -d "$INSTALL_DIR" ]]; then
+            echo "Adding install directory to GITHUB_PATH: $INSTALL_DIR"
+            echo "$INSTALL_DIR" >> "$GITHUB_PATH"
+          fi
+        fi
+
     - name: Install PowerShell (Windows)
       if: runner.os == 'Windows'
       shell: powershell
       working-directory: ${{ github.action_path }}
       env:
         REQUESTED_VERSION: ${{ inputs.Version }}
+        PRERELEASE: ${{ inputs.Prerelease }}
         GITHUB_TOKEN: ${{ github.token }}
-      run: |
+      run: | # zizmor: ignore[github-env] GITHUB_PATH writes use hardcoded install dirs, not user input
         # Install-PowerShell
         Write-Host "Requested version: [$env:REQUESTED_VERSION]"
+        Write-Host "Prerelease: [$env:PRERELEASE]"
 
         # Resolve 'latest' → concrete version
         $req = $env:REQUESTED_VERSION
         if ($req -and $req.Trim().ToLower() -eq 'latest') {
-            $latest = (
-              Invoke-RestMethod -Uri 'https://api.github.com/repos/PowerShell/PowerShell/releases/latest' `
-              -Headers @{
-                'Accept' = 'application/vnd.github+json'
-                'Authorization' = "Bearer $($env:GITHUB_TOKEN)"
+            $headers = @{
+                'Accept'               = 'application/vnd.github+json'
+                'Authorization'        = "Bearer $($env:GITHUB_TOKEN)"
                 'X-GitHub-Api-Version' = '2022-11-28'
-              }
-            ).tag_name.TrimStart('v')
-            Write-Host "Latest stable PowerShell release detected: $latest"
+            }
+            if ($env:PRERELEASE -eq 'true') {
+                $releases = Invoke-RestMethod -Uri 'https://api.github.com/repos/PowerShell/PowerShell/releases' -Headers $headers
+                $latestRelease = $releases | Where-Object { $_.prerelease -eq $true } | Select-Object -First 1
+                if (-not $latestRelease) {
+                    Write-Host "Error: No prerelease PowerShell releases are available from GitHub."
+                    exit 1
+                }
+                $latest = $latestRelease.tag_name.TrimStart('v')
+                Write-Host "Latest prerelease PowerShell version detected: $latest"
+            } else {
+                $latest = (Invoke-RestMethod -Uri 'https://api.github.com/repos/PowerShell/PowerShell/releases/latest' -Headers $headers).tag_name.TrimStart('v')
+                if (-not $latest) {
+                    Write-Host "Error: Failed to resolve latest stable PowerShell release from GitHub."
+                    exit 1
+                }
+                Write-Host "Latest stable PowerShell release detected: $latest"
+            }
             $env:REQUESTED_VERSION = $latest
         } elseif ([string]::IsNullOrWhiteSpace($req)) {
             Write-Host "Error: Version input is required (or use 'latest')"
@@ -198,14 +287,22 @@ runs:
         }
 
         # Downgrade detection
+        # Strip prerelease suffix for [version] comparison (e.g. '7.6.0-preview.6' → '7.6.0')
         $isDowngrade = $false
         if ($detected -and $detected -ne $env:REQUESTED_VERSION) {
           try {
-            $detectedVersion  = [version]$detected
-            $requestedVersion = [version]$env:REQUESTED_VERSION
+            $detectedBase  = ($detected -split '-')[0]
+            $requestedBase = ($env:REQUESTED_VERSION -split '-')[0]
+            $detectedVersion  = [version]$detectedBase
+            $requestedVersion = [version]$requestedBase
             if ($detectedVersion -gt $requestedVersion) {
               Write-Host "Downgrade detected: $detected → $($env:REQUESTED_VERSION)"
               $isDowngrade = $true
+            } elseif ($detectedVersion -eq $requestedVersion -and $detected -ne $env:REQUESTED_VERSION) {
+              # Same base version but different prerelease label — MSI installers cannot
+              # handle cross-prerelease changes in-place, so force uninstall first.
+              Write-Host "Prerelease version change detected (same base, different label): $detected → $($env:REQUESTED_VERSION)"
+              $isDowngrade = $true
             } else {
               Write-Host "Upgrade detected: $detected → $($env:REQUESTED_VERSION)"
             }
@@ -224,13 +321,14 @@ runs:
             'HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\*'
           )
 
+          $isDetectedPreview = $detected -match '-preview|-rc'
           $pwshEntries = Get-ItemProperty -Path $regPaths -ErrorAction SilentlyContinue |
             Where-Object {
               $_.Publisher     -eq 'Microsoft Corporation'     -and
               $_.DisplayName   -like 'PowerShell 7*'           -and
-              $_.DisplayName   -notlike '*Preview*'            -and
+              $(if ($isDetectedPreview) { $_.DisplayName -like '*Preview*' } else { $_.DisplayName -notlike '*Preview*' }) -and
               $_.DisplayVersion -and
-              $_.DisplayVersion.StartsWith($detected)
+              ($_.DisplayVersion -match "^$([regex]::Escape(($detected -split '-')[0]))([.\-]|$)" -or $_.DisplayVersion -eq ($detected -split '-')[0])
             }
 
           $targetEntry = $pwshEntries | Select-Object -First 1
@@ -283,3 +381,20 @@ runs:
         }
 
         Write-Host "Installation complete. PowerShell [$($env:REQUESTED_VERSION)] is now available."
+
+        # Add the install directory to GITHUB_PATH so subsequent `shell: pwsh` steps
+        # resolve to the version we just installed — even for preview builds whose
+        # install directory (7-preview) is not on the runner's default PATH.
+        $isPrerelease = $env:REQUESTED_VERSION -match '-'
+        $majorVersion = ($env:REQUESTED_VERSION -split '[.\-]')[0]
+        $installDir = if ($isPrerelease) {
+            "$env:ProgramFiles\PowerShell\$majorVersion-preview"
+        } else {
+            "$env:ProgramFiles\PowerShell\$majorVersion"
+        }
+        if (Test-Path $installDir) {
+            Write-Host "Adding install directory to GITHUB_PATH: $installDir"
+            Add-Content -Path $env:GITHUB_PATH -Value $installDir
+        } else {
+            Write-Host "Warning: Expected install directory not found: $installDir"
+        }