next.js

d8fdb6ff - Simplify running test apps locally with `ppr` or `dynamicIO` enabled (#81668)

Simplify running test apps locally with `ppr` or `dynamicIO` enabled (#81668) We want to respect the `__NEXT_EXPERIMENTAL_PPR` and `__NEXT_EXPERIMENTAL_CACHE_COMPONENTS` environment variables in the test apps, so that we can run them locally with these features enabled without needing to modify the config files. So we're removing the requirement that `__NEXT_TEST_MODE` needs to be set at the same time. Usually you don't want to set this variable locally because it also changes other behavior in a few places. This really has no downside, because it was already possible for users to set both variables and affect the flags, and now this can be done with a single variable. It allows us to keep the noise out of the test app's next config files. We're also moving the assignments from the default config into `enforceExperimentalFeatures` to get the nice output when printing the experimental features in the CLI.