Install external language toolchains

Back to External process languages.

Python requires Python 3; C# requires the .NET SDK; C/C++ requires Clang, GCC, or MSVC; Java requires java and javac; PHP requires PHP CLI. Run cargo xtask doctor to see the exact executable and version Rustic discovered.

On Windows, Setup offers these external toolchains as optional Gameplay Languages and installs every selected item through Windows Package Manager. Lua, JavaScript, and HTML/CSS are bundled. Additional toolchains can be installed later using Rustic Game Engine > Language Toolchain Manager in the Start menu or by rerunning Setup.

Setup uses one hidden PowerShell process for all selected toolchains and skips tools that are already installed. A PowerShell launch failure or a WinGet initialization failure stops the batch instead of retrying the failing host for every language. Rustic itself remains installed; you can start with the bundled languages and retry optional tools later from Language Toolchain Manager.

If Setup reports error 142 or 0xc0000142, keep the full message: these are distinct codes, and the failing executable matters. The Setup failure dialog includes the launch error or exit code and the path to its log. Setup saves a log in %TEMP% (Setup Log ...txt) automatically; use /LOG="C:\path\setup.log" to choose a location. If PowerShell started, check the original user's %LOCALAPPDATA%\Rustic Game Engine\logs\toolchain-install.log for the failed package and WinGet output. If no transcript exists, inspect the Setup log for a PowerShell startup failure. Repair the failing PowerShell or Microsoft App Installer installation before retrying; opening Windows Terminal is not required by Setup.