wroclaw-git-backups/nix
1
0
Fork 0
mirror of https://github.com/NixOS/nix synced 2025-07-05 12:21:48 +02:00
Code Activity

Make the Derived Path family of types inductive for dynamic derivations

Browse source 
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 commit is contained in:
John Ericson 2023-01-15 17:39:04 -05:00
parent d00fe5f225
commit 60b7121d2c
48 changed files with 1136 additions and 267 deletions
Download patch file Download diff file Expand all files Collapse all files

7
src/libstore/build/worker.cc
View file

@ -111,7 +111,10 @@ GoalPtr Worker::makeGoal(const DerivedPath & req, BuildMode buildMode)
{
return std::visit(overloaded {
[&](const DerivedPath::Built & bfd) -> GoalPtr {
return makeDerivationGoal(bfd.drvPath, bfd.outputs, buildMode);
if (auto bop = std::get_if<DerivedPath::Opaque>(&*bfd.drvPath))
return makeDerivationGoal(bop->path, bfd.outputs, buildMode);
else
throw UnimplementedError("Building dynamic derivations in one shot is not yet implemented.");
},
[&](const DerivedPath::Opaque & bo) -> GoalPtr {
return makePathSubstitutionGoal(bo.path, buildMode == bmRepair ? Repair : NoRepair);
@ -265,7 +268,7 @@ void Worker::run(const Goals & _topGoals)
for (auto & i : _topGoals) {
topGoals.insert(i);
if (auto goal = dynamic_cast<DerivationGoal *>(i.get())) {
topPaths.push_back(DerivedPath::Built{goal->drvPath, goal->wantedOutputs});
topPaths.push_back(DerivedPath::Built{makeConstantStorePathRef(goal->drvPath), goal->wantedOutputs});
} else if (auto goal = dynamic_cast<PathSubstitutionGoal *>(i.get())) {
topPaths.push_back(DerivedPath::Opaque{goal->storePath});
}