pretty please

k8s/Prelude.dhall

@@ -1 +1,29 @@
-https://prelude.dhall-lang.org/package.dhall sha256:10db3c919c25e9046833df897a8ffe2701dc390fa0893d958c3430524be5a43e
+{- This file provides a central `Prelude` import for the rest of the library to
+   use so that the integrity check only needs to be updated in one place
+   whenever upgrading the interpreter.
+
+   This allows the user to provide their own Prelude import using the
+   `DHALL_PRELUDE` environment variable, like this:
+
+   ```
+   $ export DHALL_PRELUDE='https://prelude.dhall-lang.org/package.dhall sha256:...'
+   ```
+
+   Note that overriding the Prelude in this way only works if this repository
+   is imported locally.  Remote imports do not have access to environment
+   variables and any attempt to import one will fall back to the next available
+   import.  To learn more, read:
+
+   * https://github.com/dhall-lang/dhall-lang/wiki/Safety-guarantees#cross-site-scripting-xss
+
+   This file also provides an import without the integrity check as a slower
+   fallback if the user is using a different version of the Dhall interpreter.
+
+   This pattern is documented in the dhall-nethack repo:
+
+   * https://github.com/dhall-lang/dhall-nethack/blob/master/Prelude.dhall
+-}
+
+  env:DHALL_PRELUDE
+? https://raw.githubusercontent.com/dhall-lang/dhall-lang/v17.0.0/Prelude/package.dhall sha256:10db3c919c25e9046833df897a8ffe2701dc390fa0893d958c3430524be5a43e
+? https://raw.githubusercontent.com/dhall-lang/dhall-lang/v17.0.0/Prelude/package.dhall