Update instructions for manual build phases execution via `nix-shell` to
cover all phases. There is no easy way of getting those commands, so it
makes a sense to have them all properly documented.
While the word 'simply' is usually added to encourage readers, it often has the
opposite effect and may even appear condescending, especially when the reader
runs into trouble trying to apply the suggestions from the documentation. It is
almost always an improvement to simply drop the word from the sentence.
(there are more possible improvements like this, we can apply those in separate
PRs)
* doc/stdenv: rewrite manual build procedure to be closer to an auto-build
This is based on
<https://jade.fyi/blog/building-nix-derivations-manually/> plus some
more original research.
The previous version of this section did not work for your choice of
simple Haskell package, e.g. haskellPackages.hscolour, due to things
like `compileBuildDriverPhase` and other custom phases that it
does not address at all.
It seems more correct to use genericBuild in development to harmonize it
with what is actually done.
I feel a little bit like I am committing a sin by suggesting using the
experimental CLI in the manual (afaict I am the first to do this), but I
have given the old version of the command, and there are justifiable
reasons to do it:
* The noted limitations with env-vars are fixed. The one with the
non-empty temp directory was one I ran into myself and oh boy was that
not fun to debug.
* Additionally the outputs are set *before* sourcing `setup.sh`: there
is an issue with nix-shell where the original version of `$out` winds
up in `NIX_LDFLAGS` due to _addRpathPrefix, which means that resulting
executables may not run properly.
It is sad that `nix develop` propagates a wrong value of `SHELL` to
builders, though. It is equally sad that `nix-shell` is essentially
abandoned upstream, with undocumented and not insignificant differences
from `nix develop`.
For the exact script differences:
17e6b85d05/src/nix-build/nix-build.cc (L516-L551)db026103b1/src/nix/get-env.sh
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
* nixpkgs manual: add an alternative example in stdenv-separateDebugInfo
This change gets rid of the indirect reference to `nix-env -i` usage
and shows how to achieve the same goal with a shell expression.
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
also updates nixdoc to 2.3.0. the nixdoc update is not a separate commit
because that would leave the manual build broken for one commit,
potentially breaking bisects and rebases.
pandoc recognizes `::: note` admonitions, nixos-render-docs only
recognizes `::: {.note}`. surprisingly pandoc also emits the correct
docbook tags for `[](#xref)`s, so we can use that too.
without stable ids on headings we cannot generate stable links to these
headings. nrd complains about this, but the current docbook workflow
does not.
a few generated ids remain, mostly in examples and footnotes. most of
the examples are generated by nixdoc (which has since gained MD export
functions, and the MD export does generate IDs).
Closes #16182
This improves the error message
Error: _assignFirst found no valid variant!
which occurred when the set of outputs was not sufficient to set
the various outputDev, outputBin, etc variables. Specifically, this
would mean that "out" is not among the outputs, which is valid for
a derivation.
This changes the message to something like
error: _assignFirst: could not find a non-empty variable to assign to outputDev. The following variables were all unset or empty: dev out.
If you did not define an "out" output, make sure to define all the specific required outputs: define an output for one of the unset variables.
While this isn't a full explanation of what stdenv can and can not do,
I think it's vast improvement over the 0 bits of information that it
used to provide. This at least gives a clue as to what's going on, and
even suggests a fix, although probably multiple such fixes are required
in an instance where someone starts with a no-out derivation from scratch
(and decide to persist).
The nixpkgs manual contains references to both sri hash and explicit
sha256 attributes. This is at best confusing to new users. Since the
final destination is exclusive use of sri hashes, see nixos/rfcs#131,
might as well push new users in that direction gently.
Notable exceptions to sri hash support are builtins.fetchTarball,
cataclysm-dda, coq, dockerTools.pullimage, elixir.override, and
fetchCrate. None, other than builtins.fetchTarball, are fundamentally
incompatible, but all currently accept explicit sha256 attributes as
input. Because adding backwards compatibility is out of scope for this
change, they have been left intact, but migration to sri format has been
made for any using old hash formats.
All hashes have been manually tested to be accurate, and updates were
only made for missing upstream artefacts or bugs.
