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`.
This reverts commit b67ee6e861.
https://github.com/NixOS/nixpkgs/issues/202244
error: a string that refers to a store path cannot be appended to a path, at /etc/nixos/nix/nixos-unstable/lib/sources.nix:193:30
appears to happen when there's a nixpkgs git submodule
> So one of the things that is different for a git submodule is that the .git folder isn't a folder, it's a textfile that contains (in my case) this:
> $ cat nix/nixos-unstable/.git
> gitdir: ../../.git/modules/nixpkgs
so that it doesn't make the manual build fail
> Apparently this is related to the combination of this new function not getting exported from the file, while still getting documented.
The main purpose of this PR is to make the basis for
`mkSkeletonFromList`'s decision between `cpu-kernel-libcabi` vs
`cpu-vendor-os` clear, without changing its behavior. The existing
code obscures this decision behind a sequence of prioritized matches
(i.e. `if-then`) which jump around between different coordinates.
Two side benefits of this PR:
1. It makes the root cause of #165836 obvious: we are missing a case
for `cpu-vendor-libcabi`. This is why nixpkgs stumbles over
`*-none-*`.
2. It illuminates some very weird corner cases in the existing
logic, like `*-${vendor}-ghcjs` overriding the `vendor` field,
and `mingw32` being transformed into `windows` in some cases.
Co-authored-by: John Ericson <git@JohnEricson.me>
This requires us to avoid the `tryEval` + `throw` combination,
because throw is strict in its error message, and we don't want
to drop our single clue when `commitIdFromGitRepo` is used
incorrectly.
It gives a warning on the lazy-trees branch of Nix
(NixOS/nix#6530)
"warning: applying 'toString' to path '...' and then accessing it is deprecated, at '...'"
'else toString (/. + "${base}/${path}");' at line 183 may still cause a warning but i don't know how
to reach that codepath and test so im leaving it untouched
changing it to 'else /. + "${base}/${path}";'
caused this error
```
error: a string that refers to a store path cannot be appended to a path
at /home/systems/nixpkgs/lib/sources.nix:183:20:
182| then path
183| else /. + "${base}/${path}";
| ^
184| in if pathIsRegularFile path
```
It gives a warning on the lazy-trees branch of Nix
(NixOS/nix#6530)
one of these was also giving me an error (the one in lib/trivial probably)
```
$ nix build
warning: applying 'toString' to path '/home/artturin/nixgits/my-nixpkgs/nixos/modules/installer/sd-card/sd
-image-aarch64.nix' and then accessing it is deprecated, at /home/artturin/nixgits/my-nixpkgs/lib/modules.
nix:349:99
warning: applying 'toString' to path '/home/artturin/nixgits/my-nixpkgs/.git' and then accessing it is dep
recated, at /home/artturin/nixgits/my-nixpkgs/lib/sources.nix:35:32
warning: applying 'toString' to path '/home/artturin/nixgits/my-nixpkgs/nixos/modules/system/etc/etc.nix'
and then accessing it is deprecated, at «stdin»:0
warning: applying 'toString' to path '/home/artturin/nixgits/my-nixpkgs/nixos/modules/system/etc/etc-activ
ation.nix' and then accessing it is deprecated, at «stdin»:0
warning: applying 'toString' to path '/home/artturin/nixgits/my-nixpkgs/nixos/modules/installer/sd-card/sd
-image-aarch64.nix' and then accessing it is deprecated, at «stdin»:0
error: cannot decode virtual path '/nix/store/virtual0000000000000000000000005-source'
(use '--show-trace' to show detailed location information)
```
A tricky thing about FreeBSD is that there is no stable ABI across
versions. That means that putting in the version as part of the config
string is paramount.
We have a parsed represenation that separates name versus version to
accomplish this. We include FreeBSD versions 12 and 13 to demonstrate
how it works.
