The new derivation should evaluate only if the old derivation does.
Sadly this means that the old derivation cannot depend on the new one
any more, which was used by xorgserver on Darwin. But this is not a
problem as `overrideAttrs` can (and should) usually be used instead.
This change allowed catching an invalid `meta.platforms` in the linux_rpi
kernels, which use `overrideDerivation`.
In the current implementation of Nix, this list would be allocated
over and over. Iirc pennae tried to optimize static list allocation,
but gained no significant performance improvement.
Yes, this function name is inconveniently long, but it is important
for the name to explicitly reference the function and not be mistaken
for the implicit string conversions, which only happen for a smaller
set of values.
If all the docs are auto-generated, it should be easier to convert
them to Commonmark.
Co-Authored-By: Valentin Gagarin <valentin.gagarin@tweag.io>
Co-Authored-By: Silvan Mosberger <contact@infinisil.com>
Render un`_type`d defaults and examples as `literalExpression`s using
`lib.generators.toPretty` so that consumers don't have to reinvent Nix
pretty-printing. `renderOptionValue` is kept internal for now intentionally.
Make `toPretty` print floats as valid Nix values (without a tilde).
Get rid of the now-obsolete `substSpecial` function.
Move towards disallowing evaluation of packages in the manual by
raising a warning on `pkgs.foo.{outPath,drvPath}`; later, this should
throw an error. Instead, module authors should use `literalExpression`
and `mkPackageOption`.
With the goal of making `toPretty` suitable for rendering option
values, render derivations as `<derivation foo-1.0>` instead of
`<derivation /nix/store/…-foo-1.0.drv>`.
This is to avoid causing sudden evaluation errors for out-of-tree
projects that have options with `default = pkgs.someUnfreePackage;` and
no `defaultText`.
Add a section on ordering option definitions.
Also mention `mkDefault` in the section on `mkOverride`.
Clarify the code a bit by renaming `defaultPriority` to
`defaultOverridePriority` and introducing `defaultOrderPriority`.
Add trace items that provide context for a failed definition that
can not be caught within the Nix language.
This also adds a test for the `tryEval` behavior of `showDefs`.
There's no need to use `unsafeDiscardStringContext` since
ee7fe64c0a
(Nix 1.8).
Also the separator can't have a context since `builtins.split` would fail, so
we can assume it doesn't.
