I don't love the way this code looks. There are two larger problems:
- eval, build/scratch, destination stores (#5025) should have different
types to reflect the fact that they are used for different purposes
and those purposes correspond to different operations. It should be
impossible to "use the wrong store" in my cases.
- Since drvs can end up in both the eval and build/scratch store, we
should have some sort of union/layered store (not on the file sytem
level, just conceptual level) that allows accessing both. This would
get rid of the ugly "check both" boilerplate in this PR.
Still, it might be better to land this now / soon after minimal cleanup,
so we have a concrete idea of what problem better abstractions are
supposed to solve.
We use the same nested map representation we used for goals, again in
order to save space. We might someday want to combine with `inputDrvs`,
by doing `V = bool` instead of `V = std::set<OutputName>`, but we are
not doing that yet for sake of a smaller diff.
The ATerm format for Derivations also needs to be extended, in addition
to the in-memory format. To accomodate this, we added a new basic
versioning scheme, so old versions of Nix will get nice errors. (And
going forward, if the ATerm format changes again the errors will be even
better.)
`parsedStrings`, an internal function used as part of parsing
derivations in A-Term format, used to consume the final `]` but expect
the initial `[` to already be consumed. This made for what looked like
unbalanced brackets at callsites, which was confusing. Now it consumes
both which is hopefully less confusing.
As part of testing, we also created a unit test for the A-Term format for
regular non-experimental derivations too.
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
Apply suggestions from code review
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
Types converted:
- `NixStringContextElem`
- `OutputsSpec`
- `ExtendedOutputsSpec`
- `DerivationOutput`
- `DerivationType`
Existing ones mostly conforming the pattern cleaned up:
- `ContentAddressMethod`
- `ContentAddressWithReferences`
The `DerivationGoal::derivationType` field had a bogus initialization,
now caught, so I made it `std::optional`. I think #8829 can make it
non-optional again because it will ensure we always have the derivation
when we construct a `DerivationGoal`.
See that issue (#7479) for details on the general goal.
`git grep 'Raw::Raw'` indicates the two types I didn't yet convert
`DerivedPath` and `BuiltPath` (and their `Single` variants) . This is
because @roberth and I (can't find issue right now...) plan on reworking
them somewhat, so I didn't want to churn them more just yet.
Co-authored-by: Eelco Dolstra <edolstra@gmail.com>
We want to be able to write down `foo.drv^bar.drv^baz`:
`foo.drv^bar.drv` is the dynamic derivation (since it is itself a
derivation output, `bar.drv` from `foo.drv`).
To that end, we create `Single{Derivation,BuiltPath}` types, that are
very similar except instead of having multiple outputs (in a set or
map), they have a single one. This is for everything to the left of the
rightmost `^`.
`NixStringContextElem` has an analogous change, and now can reuse
`SingleDerivedPath` at the top level. In fact, if we ever get rid of
`DrvDeep`, `NixStringContextElem` could be replaced with
`SingleDerivedPath` entirely!
Important note: some JSON formats have changed.
We already can *produce* dynamic derivations, but we can't refer to them
directly. Today, we can merely express building or example at the top
imperatively over time by building `foo.drv^bar.drv`, and then with a
second nix invocation doing `<result-from-first>^baz`, but this is not
declarative. The ethos of Nix of being able to write down the full plan
everything you want to do, and then execute than plan with a single
command, and for that we need the new inductive form of these types.
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
Co-authored-by: Valentin Gagarin <valentin.gagarin@tweag.io>
This enables nix to correctly report what will be fetched in the case
that everything is a cache hit.
Note however that if an intermediate build of something which is not
cached could still cause products to end up being substituted if the
intermediate build results in a CA path which is in the cache.
Fixes#8615.
Signed-off-by: Peter Waller <p@pwaller.net>
This makes it more useful. In general, the derivation will be in one
store, and the realisation info is in another.
This also helps us avoid duplication. See how `resolveDerivedPath` is
now simpler because it uses `queryPartialDerivationOutputMap`. In #8369
we get more flavors of derived path, and need more code to resolve them
all, and this problem only gets worse.
The fact that we need a new method to deal with the multiple dispatch is
unfortunate, but this generally relates to the fact that `Store` is a
sub-par interface, too bulky/unwieldy and conflating separate concerns.
Solving that is out of scope of this PR.
This is part of the RFC 92 work. See tracking issue #6316
In other words, use a plain `ContentAddress` not
`ContentAddressWithReferences` for `DerivationOutput::CAFixed`.
Supporting fixed output derivations with (fixed) references would be a
cool feature, but it is out of scope at this moment.
`&` without space before is far more common on this codebase than I
thought, so it is not worth changing just this one file. Maybe we will
adopt a formatter someday but until then this is fine.
This should be a non-empty set, and so we don't want people doing this
by accident. We remove the zero-0 constructor with a little inheritance
trickery.
`DerivedPath::Built` and `DerivationGoal` were previously using a
regular set with the convention that the empty set means all outputs.
But it is easy to forget about this rule when processing those sets.
Using `OutputSpec` forces us to get it right.
1. `DerivationOutput` now as the `std::variant` as a base class. And the
variants are given hierarchical names under `DerivationOutput`.
In 8e0d0689be @matthewbauer and I
didn't know a better idiom, and so we made it a field. But this sort
of "newtype" is anoying for literals downstream.
Since then we leaned the base class, inherit the constructors trick,
e.g. used in `DerivedPath`. Switching to use that makes this more
ergonomic, and consistent.
2. `store-api.hh` and `derivations.hh` are now independent.
In bcde5456cc I swapped the dependency,
but I now know it is better to just keep on using incomplete types as
much as possible for faster compilation and good separation of
concerns.
I had started the trend of doing `std::visit` by value (because a type
error once mislead me into thinking that was the only form that
existed). While the optomizer in principle should be able to deal with
extra coppying or extra indirection once the lambdas inlined, sticking
with by reference is the conventional default. I hope this might even
improve performance.
That doesn’t really make sense with CA derivations (and wasn’t even
really correct before because of FO derivations, though that probably
didn’t matter much in practice)
