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>
Pass this around instead of `Source &` and `Sink &` directly. This will
give us something to put the protocol version on once the time comes.
To do this ergonomically, we need to expose `RemoteStore::Connection`,
so do that too. Give it some more API docs while we are at it.
See API docs on that struct for why. The pasing as as template argument
doesn't yet happen in that commit, but will instead happen in later
commit.
Also make `WorkerOp` (now `Op`) and enum struct. This led us to catch
that two operations were not handled!
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
This is generally a fine practice: Putting implementations in headers
makes them harder to read and slows compilation. Unfortunately it is
necessary for templates, but we can ameliorate that by putting them in a
separate header. Only files which need to instantiate those templates
will need to include the header with the implementation; the rest can
just include the declaration.
This is now documenting in the contributing guide.
Also, it just happens that these polymorphic serializers are the
protocol agnostic ones. (Worker and serve protocol have the same logic
for these container types.) This means by doing this general template
cleanup, we are also getting a head start on better indicating which
code is protocol-specific and which code is shared between protocols.
This is the more typically way to do [Argument-dependent
lookup](https://en.cppreference.com/w/cpp/language/adl)-leveraging
generic serializers in C++. It makes the relationship between the `read`
and `write` methods more clear and rigorous, and also looks more
familiar to users coming from other languages that do not have C++'s
libertine ad-hoc overloading.
I am returning to this because during the review in
https://github.com/NixOS/nix/pull/6223, it came up as something that
would make the code easier to read --- easier today hopefully already,
but definitely easier if we were have multiple codified protocols with
code sharing between them as that PR seeks to accomplish.
If I recall correctly, the main criticism of this the first time around
(in 2020) was that having to specify the type when writing, e.g.
`WorkerProto<MyType>::write`, was too verbose and cumbersome. This is
now addressed with the `workerProtoWrite` wrapper function.
This method is also the way `nlohmann::json`, which we have used for a
number of years now, does its serializers, for what its worth.
This reverts commit 45a0ed82f0. That
commit in turn reverted 9ab07e99f5.
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.
In many cases we are dealing with a collection of realisations, they are
all outputs of the same derivation. In that case, we don't need
"derivation hashes modulos" to be part of our map key, because the
output names alone will be unique. Those hashes are still part of the
realisation proper, so we aren't loosing any information, we're just
"normalizing our schema" by narrowing the "primary key".
Besides making our data model a bit "tighter" this allows us to avoid a
double `for` loop in `DerivationGoal::waiteeDone`. The inner `for` loop
was previously just to select the output we cared about without knowing
its hash. Now we can just select the output by name directly.
Note that neither protocol is changed as part of this: we are still
transferring `DrvOutputs` over the wire for `BuildResult`s. I would only
consider revising this once #6223 is merged, and we can mention protocol
versions inside factored-out serialization logic. Until then it is
better not change anything because it would come a the cost of code
reuse.
If my memory is correct, @edolstra objected to modifying `wantedOutputs`
upon falling back to doing a build (as we did before), because we should
only modify it in response to new requests --- *actual* wants --- and
not because we are "incidentally" building all the outptus beyond what
may have been requested.
That's a fair point, and the alternative is to replace the boolean soup
with proper enums: Instead of modifying `wantedOuputs` som more, we'll
modify `needsRestart` to indicate we are passed the need.
In https://github.com/NixOS/nix/pull/6311#discussion_r834863823, I
realized since derivation goals' wanted outputs can "grow" due to
overlapping dependencies (See `DerivationGoal::addWantedOutputs`, called
by `Worker::makeDerivationGoalCommon`), the previous bug fix had an
unfortunate side effect of causing more pointless rebuilds.
In paticular, we have this situation:
1. Goal made from `DerivedPath::Built { foo, {a} }`.
2. Goal gives on on substituting, starts building.
3. Goal made from `DerivedPath::Built { foo, {b} }`, in fact is just
modified original goal.
4. Though the goal had gotten as far as building, so all outputs were
going to be produced, `addWantedOutputs` no longer knows that and so
the goal is flagged to be restarted.
This might sound far-fetched with input-addressed drvs, where we usually
basically have all our goals "planned out" before we start doing
anything, but with CA derivation goals and especially RFC 92, where *drv
resolution* means goals are created after some building is completed, it
is more likely to happen.
So the first thing to do was restore the clearing of `wantedOutputs` we
used to do, and then filter the outputs in `buildPathsWithResults` to
only get the ones we care about.
But fix also has its own side effect in that the `DerivedPath` in the
`BuildResult` in `DerivationGoal` cannot be trusted; it is merely the
*first* `DerivedPath` for which this goal was originally created.
To remedy this, I made `BuildResult` be like it was before, and instead
made `KeyedBuildResult` be a subclass wit the path. Only
`buildPathsWithResults` returns `KeyedBuildResult`s, everything else
just becomes like it was before, where the "key" is unambiguous from
context.
I think separating the "primary key" field(s) from the other fields is
good practical in general anyways. (I would like to do the same thing
for `ValidPathInfo`.) Among other things, it allows constructions like
`std::map<Key, ThingWithKey>` where doesn't contain duplicate keys and
just precludes the possibility of those duplicate keys being out of
sync.
We might leverage the above someday to overload `buildPathsWithResults`
to take a *set* of return a *map* per the above.
-----
Unfortunately, we need to avoid C++20 strictness on designated
initializers.
(BTW
https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p2287r1.html
this offers some new syntax for this use-case. Hopefully this will be
adopted and we can eventually use it.)
No having that yet, maybe it would be better to not make
`KeyedBuildResult` a subclass to just avoid this.
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
This fixes the issue that `nix-build`, without experimental feature
'nix-command' enabled, recommends the experimental CLI `nix log` to view
build logs. Now it'll recommend the stable `nix-store -l` CLI instead.
Fixes https://github.com/NixOS/nix/issues/8118
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.
This makes 'nix develop' set the Linux personality in the same way
that the actual build does, allowing a command like 'nix develop
nix#devShells.i686-linux.default' on x86_64-linux to work correctly.
These only functioned if a very narrow combination of conditions held:
- The result path does not yet exist (--check did not result in
repeated builds), AND
- The result path is not available from any configured substituters, AND
- No remote builders that can build the path are available.
If any of these do not hold, a derivation would be built 0 or 1 times
regardless of the repeat option. Thus, remove it to avoid confusion.
It occurred when a output of the dependency was already available,
so it didn't need rebuilding and didn't get added to the
inputDrvOutputs.
This process-related info wasn't suitable for the purpose of finding
the actual input paths for the builder. It is better to do this in
absolute terms by querying the store.
readDerivation is pretty slow, and while it may not be significant for
some use cases, on things like ghc-nix where we have thousands of
derivations is really slows things down.
So, this just doesn’t do the impure derivation check if the impure
derivation experimental feature is disabled. Perhaps we could cache
the result of isPure() and keep the check, but this is a quick fix to
for the slowdown introduced with impure derivations features in 2.8.0.
Once a derivation goal has been completed, we check whether or not
this goal was meant to be repeated to check its output.
An early return branch was preventing the worker to reach that repeat
code branch, hence breaking the --check command (#2619).
It seems like this early return branch is an artifact of a passed
refactoring. As far as I can tell, buildDone's main branch also
cleanup the tmp directory before returning.
Impure derivations are derivations that can produce a different result
every time they're built. Example:
stdenv.mkDerivation {
name = "impure";
__impure = true; # marks this derivation as impure
outputHashAlgo = "sha256";
outputHashMode = "recursive";
buildCommand = "date > $out";
};
Some important characteristics:
* This requires the 'impure-derivations' experimental feature.
* Impure derivations are not "cached". Thus, running "nix-build" on
the example above multiple times will cause a rebuild every time.
* They are implemented similar to CA derivations, i.e. the output is
moved to a content-addressed path in the store. The difference is
that we don't register a realisation in the Nix database.
* Pure derivations are not allowed to depend on impure derivations. In
the future fixed-output derivations will be allowed to depend on
impure derivations, thus forming an "impurity barrier" in the
dependency graph.
* When sandboxing is enabled, impure derivations can access the
network in the same way as fixed-output derivations. In relaxed
sandboxing mode, they can access the local filesystem.
This avoids an infinite loop in the final test in
tests/binary-cache.sh. I think this was only not triggered previously
by accident (because we were clearing wantedOutputs in between).
