feat(msix): generate App Installer file for automatic updates

Generate an install-{arch}.appinstaller file alongside each MSIX package.
The file lives at the stable CDN URL (releases/latest) and points to the
immutable versioned MSIX, so Windows App Installer checks for updates on
launch (daily) and via a background task, updating silently without user
interaction.

The release workflow uploads the .appinstaller files as release assets
and to the CDN with the application/appinstaller content type.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01X95PpvsxLn7q5S54kTPYhY

Author: claude

.github/workflows/release.yml

@@ -132,6 +132,7 @@ jobs:
           name: msix-artifact-${{ matrix.arch }}
           path: |
             packages/msix/out/install-${{ matrix.arch }}.msix
+            packages/msix/out/install-${{ matrix.arch }}.appinstaller
   release:
     runs-on: ubuntu-latest
     needs:
@@ -149,7 +150,9 @@ jobs:
         run: |
           echo v${{ needs.changelog.outputs.version }} > version.txt
           az storage blob upload-batch --destination releases/v${{ needs.changelog.outputs.version }} --source .
+          az storage blob upload-batch --destination releases/v${{ needs.changelog.outputs.version }} --overwrite true --source . --pattern "*.appinstaller" --content-type "application/appinstaller"
           az storage blob upload-batch --destination releases/latest --overwrite true --source .
+          az storage blob upload-batch --destination releases/latest --overwrite true --source . --pattern "*.appinstaller" --content-type "application/appinstaller"
       - name: Create draft release 📝
         uses: softprops/action-gh-release@3d0d9888cb7fd7b750713d6e236d1fcb99157228
         with:

packages/msix/README.md

@@ -15,12 +15,24 @@ the repository's `dist` folder.
 ./build.ps1 -Architecture x64 -Version "1.3.37"
 ```
 
-The package is created at `out/install-x64.msix`.
+The package is created at `out/install-x64.msix`, along with an App Installer
+file at `out/install-x64.appinstaller`.
+
+The `.appinstaller` file references the published package on the CDN and enables
+automatic updates: Windows re-checks the stable URL it was installed from
+(daily on launch and via a background task) and updates the package silently
+when a new version is available.
 
 ## Install the package
 
 ```powershell
 Add-AppxPackage -Path ./out/install-x64.msix
 ```
 
+## Install via App Installer (with auto-update)
+
+```powershell
+Add-AppxPackage -AppInstallerFile https://cdn.ohmyposh.dev/releases/latest/install-x64.appinstaller
+```
+
 [Windows SDK]: https://developer.microsoft.com/en-us/windows/downloads/windows-sdk/

packages/msix/build.ps1

@@ -21,6 +21,10 @@
 .PARAMETER Copy
     When specified, copies the appropriate executable from the dist folder before packaging.
 
+.PARAMETER DownloadUrl
+    The base URL where releases are published, used in the generated App Installer file.
+    Defaults to "https://cdn.ohmyposh.dev/releases".
+
 .EXAMPLE
     .\build.ps1 -Architecture x64 -Version "1.2.3" -Copy
 
@@ -32,7 +36,7 @@
     Creates and signs the MSIX package for arm64 architecture with version 1.2.3.
 
 .OUTPUTS
-    Creates install-{Architecture}.msix in the 'out' directory.
+    Creates install-{Architecture}.msix and install-{Architecture}.appinstaller in the 'out' directory.
 
 .NOTES
     Requires the Windows SDK for MSIX packaging and signing.
@@ -56,7 +60,11 @@ param(
     [switch]$Sign,
 
     [Parameter()]
-    [switch]$Copy
+    [switch]$Copy,
+
+    [Parameter()]
+    [ValidateNotNullOrEmpty()]
+    [string]$DownloadUrl = "https://cdn.ohmyposh.dev/releases"
 )
 
 # Set error handling preferences
@@ -226,6 +234,35 @@ catch {
     throw
 }
 
+Write-Verbose "Creating App Installer file" -Verbose
+
+try {
+    $appInstallerPath = "$currentPath/out/install-$Architecture.appinstaller"
+    $identity = $manifestDocument.Package.Identity
+
+    # The App Installer file lives at a stable URL so Windows can poll it for updates,
+    # while the package URL is immutable per version to avoid mid-publish races.
+    $appInstaller = @"
+<?xml version="1.0" encoding="utf-8"?>
+<AppInstaller xmlns="http://schemas.microsoft.com/appx/appinstaller/2018" Version="$Version.0" Uri="$DownloadUrl/latest/install-$Architecture.appinstaller">
+  <MainPackage Name="$($identity.Name)" Version="$Version.0" Publisher="$($identity.Publisher)" ProcessorArchitecture="$Architecture" Uri="$DownloadUrl/v$Version/install-$Architecture.msix" />
+  <UpdateSettings>
+    <OnLaunch HoursBetweenUpdateChecks="24" />
+    <AutomaticBackgroundTask />
+    <ForceUpdateFromAnyVersion>true</ForceUpdateFromAnyVersion>
+  </UpdateSettings>
+</AppInstaller>
+"@
+
+    $appInstaller | Out-File -FilePath $appInstallerPath -Encoding UTF8
+
+    Write-Verbose "Created App Installer file: $appInstallerPath" -Verbose
+}
+catch {
+    Write-Error "Failed to create App Installer file: ${_}"
+    throw
+}
+
 if ($Sign) {
     $signingTools = Initialize-SigningEnvironment -SDKVersion $SDKVersion
     Invoke-PackageSigning -PackagePath $msixPackagePath -SigningTools $signingTools

website/docs/installation/windows.mdx

@@ -29,6 +29,7 @@ When using oh-my-posh inside the WSL, make sure to follow the [Linux][linux] ins
   values={[
     { label: 'winget', value: 'winget', },
     { label: 'manual', value: 'manual', },
+    { label: 'App Installer', value: 'appinstaller', },
     { label: 'chocolatey', value: 'chocolatey'},
   ]
 }>
@@ -49,6 +50,21 @@ Open a PowerShell prompt and run the following command:
 Set-ExecutionPolicy Bypass -Scope Process -Force; Invoke-Expression ((New-Object System.Net.WebClient).DownloadString('https://ohmyposh.dev/install.ps1'))
 ```
 
+</TabItem>
+<TabItem value="appinstaller">
+
+Installing via App Installer keeps Oh My Posh up to date automatically:
+Windows checks for a new version in the background and updates the package
+without any interaction needed.
+
+Open a PowerShell prompt and run the following command:
+
+```powershell
+Add-AppxPackage -AppInstallerFile https://cdn.ohmyposh.dev/releases/latest/install-x64.appinstaller
+```
+
+For ARM64, use `install-arm64.appinstaller` instead.
+
 </TabItem>
 <TabItem value="chocolatey">
 
@@ -76,6 +92,7 @@ choco install oh-my-posh
   values={[
     { label: 'winget', value: 'winget', },
     { label: 'manual', value: 'manual', },
+    { label: 'App Installer', value: 'appinstaller', },
     { label: 'chocolatey', value: 'chocolatey'},
   ]
 }>
@@ -87,6 +104,16 @@ Open a PowerShell prompt and run the following command:
 winget upgrade JanDeDobbeleer.OhMyPosh --source winget
 ```
 
+</TabItem>
+<TabItem value="appinstaller">
+
+No action needed, Windows updates Oh My Posh automatically in the background.
+To force an update check, run the install command again:
+
+```powershell
+Add-AppxPackage -AppInstallerFile https://cdn.ohmyposh.dev/releases/latest/install-x64.appinstaller
+```
+
 </TabItem>
 <TabItem value="manual">