diff options
| author | piegames <git@piegames.de> | 2022-09-16 14:14:59 +0200 |
|---|---|---|
| committer | piegames <git@piegames.de> | 2022-09-25 16:37:15 +0200 |
| commit | 0ada9fff8a86dc582ebee158107d4f942e865ab0 (patch) | |
| tree | dfac05b1913e09fa13ecfb0eb5dcfacd1e69bb65 /lib/types.nix | |
| parent | 5f379c4b68edfda8326b1c4d173b75975668ded3 (diff) | |
lib/types.nix: Document that it should not be used
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com> Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
Diffstat (limited to 'lib/types.nix')
| -rw-r--r-- | lib/types.nix | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/lib/types.nix b/lib/types.nix index 3750ba9655588..ed1d5f44064fe 100644 --- a/lib/types.nix +++ b/lib/types.nix @@ -119,8 +119,22 @@ rec { # - "composite": a phrase with an "of" connective # See the `optionDescriptionPhrase` function. , descriptionClass ? null - , # Function applied to each definition that should return true if - # its type-correct, false otherwise. + , # DO NOT USE WITHOUT KNOWING WHAT YOU ARE DOING! + # Function applied to each definition that must return false when a definition + # does not match the type. It should not check more than the root of the value, + # because checking nested values reduces laziness, leading to unnecessary + # infinite recursions in the module system. + # Further checks of nested values should be performed by throwing in + # the merge function. + # Strict and deep type checking can be performed by calling lib.deepSeq on + # the merged value. + # + # See https://github.com/NixOS/nixpkgs/pull/6794 that introduced this change, + # https://github.com/NixOS/nixpkgs/pull/173568 and + # https://github.com/NixOS/nixpkgs/pull/168295 that attempted to revert this, + # https://github.com/NixOS/nixpkgs/issues/191124 and + # https://github.com/NixOS/nixos-search/issues/391 for what happens if you ignore + # this disclaimer. check ? (x: true) , # Merge a list of definitions together into a single value. # This function is called with two arguments: the location of |