By default, builds will fail if another version of the package being built ends up in the build environment, either as a direct or indirect dependency. There are packages, however, that bootstrap their own build process and require this (for example: compilers like gcc or package systems like pip). Furthermore, these recursive builds often perform an in-place upgrade, writing over some or all the previous versions files which is typically not allowed.
The validation rule RecursiveBuild can be used to reconfigure the validation process for these scenarios:
build:
validation:
rules:
- allow: RecursiveBuild