TYPO3 Core

Removing an extension that is required by some other extension causes a crash early in bootstrap. This is especially unfortunate for the install tool.
The only solution is to remove all depending extensions from the PackageStates.php.

Note this only happens if a missing extension is a dependency of another extension.

Example:
- Use an instance with the ext:introductionpackage and remove the extension bootstrap_package.
- Try to access the install tool

Expected behaviour:
Show some usable trouble shooting screen or mark all depending extensions as inactive too. Handle this case somehow.