From 60b7121d2c6d4322b7c2e8e7acfec7b701b2d3a1 Mon Sep 17 00:00:00 2001 From: John Ericson Date: Sun, 15 Jan 2023 17:39:04 -0500 Subject: Make the Derived Path family of types inductive for dynamic derivations 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 `^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 Co-authored-by: Valentin Gagarin --- src/libstore/remote-store.cc | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) (limited to 'src/libstore/remote-store.cc') diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc index 21258daec..58f72beb9 100644 --- a/src/libstore/remote-store.cc +++ b/src/libstore/remote-store.cc @@ -656,6 +656,9 @@ static void writeDerivedPaths(RemoteStore & store, RemoteStore::Connection & con GET_PROTOCOL_MAJOR(conn.daemonVersion), GET_PROTOCOL_MINOR(conn.daemonVersion)); }, + [&](std::monostate) { + throw Error("wanted to build a derivation that is itself a build product, but the legacy 'ssh://' protocol doesn't support that. Try using 'ssh-ng://'"); + }, }, sOrDrvPath); } conn.to << ss; @@ -670,9 +673,16 @@ void RemoteStore::copyDrvsFromEvalStore( /* The remote doesn't have a way to access evalStore, so copy the .drvs. */ RealisedPath::Set drvPaths2; - for (auto & i : paths) - if (auto p = std::get_if(&i)) - drvPaths2.insert(p->drvPath); + for (const auto & i : paths) { + std::visit(overloaded { + [&](const DerivedPath::Opaque & bp) { + // Do nothing, path is hopefully there already + }, + [&](const DerivedPath::Built & bp) { + drvPaths2.insert(bp.drvPath->getBaseStorePath()); + }, + }, i.raw()); + } copyClosure(*evalStore, *this, drvPaths2); } } @@ -742,7 +752,8 @@ std::vector RemoteStore::buildPathsWithResults( }; OutputPathMap outputs; - auto drv = evalStore->readDerivation(bfd.drvPath); + auto drvPath = resolveDerivedPath(*evalStore, *bfd.drvPath); + auto drv = evalStore->readDerivation(drvPath); const auto outputHashes = staticOutputHashes(*evalStore, drv); // FIXME: expensive auto built = resolveDerivedPath(*this, bfd, &*evalStore); for (auto & [output, outputPath] : built) { @@ -750,7 +761,7 @@ std::vector RemoteStore::buildPathsWithResults( if (!outputHash) throw Error( "the derivation '%s' doesn't have an output named '%s'", - printStorePath(bfd.drvPath), output); + printStorePath(drvPath), output); auto outputId = DrvOutput{ *outputHash, output }; if (experimentalFeatureSettings.isEnabled(Xp::CaDerivations)) { auto realisation = -- cgit v1.2.3