> ## Documentation Index
> Fetch the complete documentation index at: https://ancplua.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# AL0019 - Undefined version variable

> Version variable referenced in Directory.Packages.props is not defined in Version.props

Source: [Al0019UndefinedVersionVariableAnalyzer.cs](https://github.com/ANcpLua/ANcpLua.Analyzers/blob/main/src/ANcpLua.Analyzers/Analyzers/Al0019UndefinedVersionVariableAnalyzer.cs)

## Description

Version variable referenced in Directory.Packages.props is not defined in Version.props. This causes build failures or unexpected fallback behavior when CPM cannot resolve the variable.

## Bad Code

```xml theme={null}
<!-- Directory.Packages.props -->
<PackageVersion Include="SomePackage" Version="$(UndefinedVar)" />
<!-- But UndefinedVar is never defined in Version.props -->
```

## Good Code

```xml theme={null}
<!-- Version.props -->
<PropertyGroup>
  <SomePackageVersion>13.0.3</SomePackageVersion>
</PropertyGroup>

<!-- Directory.Packages.props -->
<PackageVersion Include="SomePackage" Version="$(SomePackageVersion)" />
```

## Properties

* **Category**: VersionManagement
* **Severity**: Warning
* **Enabled by default**: True
* **Code fix available**: False

## Configuration

```editorconfig theme={null}
dotnet_diagnostic.AL0019.severity = warning
```