Ensure builds use the pinned Avalonia producer

.gitmodules

@@ -1,4 +1,3 @@
 [submodule "avalonia-src"]
 	path = avalonia-src
 	url = https://github.com/mamoreau-devolutions/Avalonia.git
-	branch = main

CONTRIBUTING.md

@@ -17,6 +17,10 @@ pwsh .\avalonia-patches\apply-avalonia-patches.ps1 -AvaloniaRoot .\avalonia-src
 pwsh .\rust\regenerate-and-build.ps1 -Configuration Release
 ```
 
+The Rust build entry points also initialize the in-repository producer at the
+revision recorded by the checkout, so a fresh or reused checkout cannot build
+against a different `avalonia-src` revision.
+
 Open `Rustolonia.slnx` to navigate the eleven Rustolonia-owned managed projects.
 Producer projects remain transitive project references, with their own build
 configuration. When adding a project to the solution, pass

rust/build-app.ps1

@@ -257,6 +257,8 @@ function Invoke-ConsumerPackage {
     Write-Host "Package layout ready at $bundle"
 }
 
+$rustoloniaRootPath = (Resolve-Path -LiteralPath $RustoloniaRoot).Path
+Initialize-LocalProducerSubmodule -RustoloniaRoot $rustoloniaRootPath -ProducerRoot $ProducerRoot
 $producer = (Resolve-Path -LiteralPath $ProducerRoot).Path
 $manifestPath = (Resolve-Path -LiteralPath $Manifest).Path
 $document = Read-ConsumerManifest $manifestPath

rust/build.ps1

@@ -16,7 +16,9 @@ $PSNativeCommandUseErrorActionPreference = $true
 
 # The Rustolonia repository root is the parent of rust/.
 $repositoryRoot = Split-Path -Parent $PSScriptRoot
+. (Join-Path $PSScriptRoot 'package-shared.ps1')
 $avaloniaRoot = Join-Path $repositoryRoot 'avalonia-src'
+Initialize-LocalProducerSubmodule -RustoloniaRoot $repositoryRoot -ProducerRoot $avaloniaRoot
 $nativeArchitecture = switch ([System.Runtime.InteropServices.RuntimeInformation]::OSArchitecture) {
     'X64' { 'x64' }
     'Arm64' { 'arm64' }

rust/package-shared.ps1

@@ -421,6 +421,44 @@ function Resolve-CallerRelativePath {
     )
 }
 
+function Initialize-LocalProducerSubmodule {
+    param(
+        [Parameter(Mandatory)][string]$RustoloniaRoot,
+        [Parameter(Mandatory)][string]$ProducerRoot
+    )
+
+    $rootPath = Resolve-CallerRelativePath $RustoloniaRoot
+    $producerPath = Resolve-CallerRelativePath $ProducerRoot
+    $expectedProducerPath = [IO.Path]::GetFullPath((Join-Path $rootPath 'avalonia-src'))
+    if (-not [String]::Equals($producerPath, $expectedProducerPath, [StringComparison]::OrdinalIgnoreCase)) {
+        return
+    }
+
+    $expectedRevision = & git -C $rootPath rev-parse 'HEAD:avalonia-src' 2>$null
+    if ($LASTEXITCODE -ne 0 -or [string]::IsNullOrWhiteSpace($expectedRevision)) {
+        throw "Cannot determine the pinned avalonia-src revision from $rootPath."
+    }
+
+    $actualRevision = if (Test-Path -LiteralPath $producerPath -PathType Container) {
+        & git -C $producerPath rev-parse HEAD 2>$null
+    }
+    else {
+        ''
+    }
+    if ($LASTEXITCODE -ne 0 -or $actualRevision -ne $expectedRevision) {
+        Write-Host "==> Initializing avalonia-src at $expectedRevision"
+        & git -C $rootPath submodule update --init --recursive -- avalonia-src
+        if ($LASTEXITCODE -ne 0) {
+            throw 'Cannot initialize avalonia-src at the pinned producer revision.'
+        }
+    }
+
+    $actualRevision = & git -C $producerPath rev-parse HEAD 2>$null
+    if ($LASTEXITCODE -ne 0 -or $actualRevision -ne $expectedRevision) {
+        throw "avalonia-src must be at $expectedRevision; found '$actualRevision'."
+    }
+}
+
 function Invoke-ArtifactSigning {
     param(
         [Parameter(Mandatory)][string]$ArtifactDirectory,

rust/regenerate-and-build.ps1

@@ -14,6 +14,8 @@ $ErrorActionPreference = 'Stop'
 $PSNativeCommandUseErrorActionPreference = $true
 # The Rustolonia repository root is the parent of rust/.
 $repositoryRoot = Split-Path -Parent $PSScriptRoot
+. (Join-Path $PSScriptRoot 'package-shared.ps1')
+Initialize-LocalProducerSubmodule -RustoloniaRoot $repositoryRoot -ProducerRoot (Join-Path $repositoryRoot 'avalonia-src')
 
 Write-Host '==> [1/4] Regenerating object-model projection IR, C# COM sources, and native ABI header'
 dotnet run --project (Join-Path $repositoryRoot 'projection' 'Avalonia.Projection.Tool') -c $Configuration -- `