price per item is printed

scripts/build_release.ps1

@@ -0,0 +1,62 @@
+param(
+    [ValidateSet('apk', 'appbundle', 'windows', 'web', 'ios', 'ipa', 'macos', 'linux')]
+    [string]$Target = 'apk',
+    [string]$FlutterCommand = 'flutter',
+    [string[]]$FlutterArguments = @()
+)
+
+$ErrorActionPreference = 'Stop'
+$projectRoot = Split-Path -Parent $PSScriptRoot
+$pubspecPath = Join-Path $projectRoot 'pubspec.yaml'
+$lockPath = Join-Path $projectRoot '.release-build.lock'
+$buildLock = $null
+$originalBytes = $null
+$updated = $false
+$succeeded = $false
+
+try {
+    # Hold an exclusive lock; the OS releases it even if PowerShell is closed.
+    $buildLock = [System.IO.File]::Open(
+        $lockPath, [System.IO.FileMode]::OpenOrCreate,
+        [System.IO.FileAccess]::ReadWrite, [System.IO.FileShare]::None
+    )
+    foreach ($argument in $FlutterArguments) {
+        if ($argument -match '^--(build-name|build-number|debug|profile|config-only)(=|$)') {
+            throw "Argument $argument ist im versionierten Release-Build nicht erlaubt."
+        }
+    }
+    $originalBytes = [System.IO.File]::ReadAllBytes($pubspecPath)
+    $source = [System.Text.Encoding]::UTF8.GetString($originalBytes)
+    $versionMatch = [regex]::Match($source, '(?m)^version:\s*(\d+)\.(\d+)\.(\d+)\+(\d+)[ \t]*\r?$')
+    if (-not $versionMatch.Success) {
+        throw 'In pubspec.yaml wird eine Version wie 1.0.0+1 erwartet.'
+    }
+    $patch = [long]::Parse($versionMatch.Groups[3].Value) + 1
+    $build = [long]::Parse($versionMatch.Groups[4].Value) + 1
+    $nextVersion = '{0}.{1}.{2}+{3}' -f $versionMatch.Groups[1].Value, $versionMatch.Groups[2].Value, $patch, $build
+    $replacement = "version: $nextVersion"
+    if ($versionMatch.Value.EndsWith("`r")) { $replacement += "`r" }
+    $nextSource = $source.Remove($versionMatch.Index, $versionMatch.Length).Insert($versionMatch.Index, $replacement)
+    [System.IO.File]::WriteAllText($pubspecPath, $nextSource, [System.Text.UTF8Encoding]::new($false))
+    $updated = $true
+
+    Push-Location $projectRoot
+    try {
+        Write-Host "Release $nextVersion ($Target) wird erstellt ..."
+        $global:LASTEXITCODE = 0
+        & $FlutterCommand build $Target --release @FlutterArguments
+        if ($LASTEXITCODE -ne 0) {
+            throw "Flutter-Build fehlgeschlagen (Exitcode $LASTEXITCODE)."
+        }
+        $succeeded = $true
+        Write-Host "Release $nextVersion erfolgreich. Die Version wurde in pubspec.yaml gespeichert."
+    } finally {
+        Pop-Location
+    }
+} finally {
+    if ($updated -and -not $succeeded) {
+        [System.IO.File]::WriteAllBytes($pubspecPath, $originalBytes)
+        Write-Host 'Build nicht erfolgreich: Bisherige Version wiederhergestellt.'
+    }
+    if ($null -ne $buildLock) { $buildLock.Dispose() }
+}

scripts/test_build_release.ps1

@@ -0,0 +1,60 @@
+$ErrorActionPreference = 'Stop'
+$projectRoot = Split-Path -Parent $PSScriptRoot
+$testRoot = Join-Path $projectRoot ('build/release-script-test-' + [guid]::NewGuid().ToString('N'))
+$testScripts = Join-Path $testRoot 'scripts'
+New-Item -ItemType Directory -Path $testScripts -Force | Out-Null
+Copy-Item -LiteralPath (Join-Path $PSScriptRoot 'build_release.ps1') -Destination $testScripts
+$pubspecPath = Join-Path $testRoot 'pubspec.yaml'
+$original = "name: test_app`r`nversion: 1.2.9+41`r`n"
+[System.IO.File]::WriteAllText($pubspecPath, $original)
+$fakeFlutter = Join-Path $testRoot 'fake_flutter.ps1'
+@'
+param([Parameter(ValueFromRemainingArguments = $true)][string[]]$BuildArguments)
+if (($BuildArguments -join ' ') -notmatch '^build (apk|windows) --release') {
+    throw 'Unexpected Flutter arguments.'
+}
+Copy-Item -LiteralPath './pubspec.yaml' -Destination './built-version.yaml' -Force
+if (Test-Path './fail-build') { $global:LASTEXITCODE = 1 } else { $global:LASTEXITCODE = 0 }
+'@ | Set-Content -LiteralPath $fakeFlutter
+$releaseScript = Join-Path $testScripts 'build_release.ps1'
+
+function Assert-Version([string]$Expected) {
+    $pubspec = [System.IO.File]::ReadAllText($pubspecPath)
+    if ($pubspec -ne "name: test_app`r`nversion: $Expected`r`n") {
+        throw "Unexpected pubspec: $pubspec"
+    }
+}
+
+& $releaseScript -FlutterCommand $fakeFlutter
+Assert-Version '1.2.10+42'
+if ([System.IO.File]::ReadAllText((Join-Path $testRoot 'built-version.yaml')) -notmatch '1\.2\.10\+42') {
+    throw 'The build did not receive the new version.'
+}
+& $releaseScript -Target windows -FlutterCommand $fakeFlutter
+Assert-Version '1.2.11+43'
+
+New-Item -ItemType File -Path (Join-Path $testRoot 'fail-build') | Out-Null
+$failureCaught = $false
+try { & $releaseScript -FlutterCommand $fakeFlutter } catch { $failureCaught = $true }
+if (-not $failureCaught) { throw 'Build failure was not reported.' }
+Assert-Version '1.2.11+43'
+
+$invalidCaught = $false
+try {
+    & $releaseScript -FlutterCommand $fakeFlutter -FlutterArguments '--build-number=99'
+} catch { $invalidCaught = $true }
+if (-not $invalidCaught) { throw 'Manual version override was accepted.' }
+Assert-Version '1.2.11+43'
+
+$lock = [System.IO.File]::Open(
+    (Join-Path $testRoot '.release-build.lock'),
+    [System.IO.FileMode]::OpenOrCreate, [System.IO.FileAccess]::ReadWrite,
+    [System.IO.FileShare]::None
+)
+$lockCaught = $false
+try {
+    try { & $releaseScript -FlutterCommand $fakeFlutter } catch { $lockCaught = $true }
+} finally { $lock.Dispose() }
+if (-not $lockCaught) { throw 'Concurrent release was not blocked.' }
+Assert-Version '1.2.11+43'
+Write-Host 'All release-script checks passed (success, repeat build, rollback, overrides, lock).'