lix/src/libcmd/installable-flake.cc
John Ericson d2162e7acd Make more string values work as installables
As discussed in #7417, it would be good to make more string values work
as installables. That is to say, if an installable refers to a value,
and the value is a string, it used to not work at all, since #7484, it
works somewhat, and this PR make it work some more.

The new cases that are added for `BuiltPath` contexts:

- Fixed input- or content-addressed derivation:

  ```
  nix-repl> hello.out.outPath
  "/nix/store/jppfl2bp1zhx8sgs2mgifmsx6dv16mv2-hello-2.12"

  nix-repl> :p builtins.getContext hello.out.outPath
  { "/nix/store/c7jrxqjhdda93lhbkanqfs07x2bzazbm-hello-2.12.drv" = { outputs = [ "out" ]; }; }

  The string matches the specified single output of that derivation, so
  it should also be valid.

- Floating content-addressed derivation:

  ```
  nix-repl> (hello.overrideAttrs (_: { __contentAddressed = true; })).out.outPath
  "/1a08j26xqc0zm8agps8anxpjji410yvsx4pcgyn4bfan1ddkx2g0"

  nix-repl> :p builtins.getContext (hello.overrideAttrs (_: { __contentAddressed = true; })).out.outPath
  { "/nix/store/qc645pyf9wl37c6qvqzaqkwsm1gp48al-hello-2.12.drv" = { outputs = [ "out" ]; }; }
  ```

  The string is not a path but a placeholder, however it also matches
  the context, and because it is a CA derivation we have no better
  option. This should also be valid.

We may also want to think about richer attrset based values (also
discussed in that issue and #6507), but this change "completes" our
string-based building blocks, from which the others can be desugared
into or at least described/document/taught in terms of.

Progress towards #7417

Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
2023-05-15 09:03:38 -04:00

223 lines
6.6 KiB
C++

#include "globals.hh"
#include "installable-flake.hh"
#include "installable-derived-path.hh"
#include "outputs-spec.hh"
#include "util.hh"
#include "command.hh"
#include "attr-path.hh"
#include "common-eval-args.hh"
#include "derivations.hh"
#include "eval-inline.hh"
#include "eval.hh"
#include "get-drvs.hh"
#include "store-api.hh"
#include "shared.hh"
#include "flake/flake.hh"
#include "eval-cache.hh"
#include "url.hh"
#include "registry.hh"
#include "build-result.hh"
#include <regex>
#include <queue>
#include <nlohmann/json.hpp>
namespace nix {
std::vector<std::string> InstallableFlake::getActualAttrPaths()
{
std::vector<std::string> res;
for (auto & prefix : prefixes)
res.push_back(prefix + *attrPaths.begin());
for (auto & s : attrPaths)
res.push_back(s);
return res;
}
Value * InstallableFlake::getFlakeOutputs(EvalState & state, const flake::LockedFlake & lockedFlake)
{
auto vFlake = state.allocValue();
callFlake(state, lockedFlake, *vFlake);
auto aOutputs = vFlake->attrs->get(state.symbols.create("outputs"));
assert(aOutputs);
state.forceValue(*aOutputs->value, [&]() { return aOutputs->value->determinePos(noPos); });
return aOutputs->value;
}
static std::string showAttrPaths(const std::vector<std::string> & paths)
{
std::string s;
for (const auto & [n, i] : enumerate(paths)) {
if (n > 0) s += n + 1 == paths.size() ? " or " : ", ";
s += '\''; s += i; s += '\'';
}
return s;
}
InstallableFlake::InstallableFlake(
SourceExprCommand * cmd,
ref<EvalState> state,
FlakeRef && flakeRef,
std::string_view fragment,
ExtendedOutputsSpec extendedOutputsSpec,
Strings attrPaths,
Strings prefixes,
const flake::LockFlags & lockFlags)
: InstallableValue(state),
flakeRef(flakeRef),
attrPaths(fragment == "" ? attrPaths : Strings{(std::string) fragment}),
prefixes(fragment == "" ? Strings{} : prefixes),
extendedOutputsSpec(std::move(extendedOutputsSpec)),
lockFlags(lockFlags)
{
if (cmd && cmd->getAutoArgs(*state)->size())
throw UsageError("'--arg' and '--argstr' are incompatible with flakes");
}
DerivedPathsWithInfo InstallableFlake::toDerivedPaths()
{
Activity act(*logger, lvlTalkative, actUnknown, fmt("evaluating derivation '%s'", what()));
auto attr = getCursor(*state);
auto attrPath = attr->getAttrPathStr();
if (!attr->isDerivation()) {
// FIXME: use eval cache?
auto v = attr->forceValue();
if (std::optional derivedPathWithInfo = trySinglePathToDerivedPaths(
v,
noPos,
fmt("while evaluating the flake output attribute '%s'", attrPath)))
{
return { *derivedPathWithInfo };
}
else
throw Error("flake output attribute '%s' is not a derivation or path", attrPath);
}
auto drvPath = attr->forceDerivation();
std::optional<NixInt> priority;
if (attr->maybeGetAttr(state->sOutputSpecified)) {
} else if (auto aMeta = attr->maybeGetAttr(state->sMeta)) {
if (auto aPriority = aMeta->maybeGetAttr("priority"))
priority = aPriority->getInt();
}
return {{
.path = DerivedPath::Built {
.drvPath = std::move(drvPath),
.outputs = std::visit(overloaded {
[&](const ExtendedOutputsSpec::Default & d) -> OutputsSpec {
std::set<std::string> outputsToInstall;
if (auto aOutputSpecified = attr->maybeGetAttr(state->sOutputSpecified)) {
if (aOutputSpecified->getBool()) {
if (auto aOutputName = attr->maybeGetAttr("outputName"))
outputsToInstall = { aOutputName->getString() };
}
} else if (auto aMeta = attr->maybeGetAttr(state->sMeta)) {
if (auto aOutputsToInstall = aMeta->maybeGetAttr("outputsToInstall"))
for (auto & s : aOutputsToInstall->getListOfStrings())
outputsToInstall.insert(s);
}
if (outputsToInstall.empty())
outputsToInstall.insert("out");
return OutputsSpec::Names { std::move(outputsToInstall) };
},
[&](const ExtendedOutputsSpec::Explicit & e) -> OutputsSpec {
return e;
},
}, extendedOutputsSpec.raw()),
},
.info = make_ref<ExtraPathInfoFlake>(
ExtraPathInfoValue::Value {
.priority = priority,
.attrPath = attrPath,
.extendedOutputsSpec = extendedOutputsSpec,
},
ExtraPathInfoFlake::Flake {
.originalRef = flakeRef,
.resolvedRef = getLockedFlake()->flake.lockedRef,
}),
}};
}
std::pair<Value *, PosIdx> InstallableFlake::toValue(EvalState & state)
{
return {&getCursor(state)->forceValue(), noPos};
}
std::vector<ref<eval_cache::AttrCursor>>
InstallableFlake::getCursors(EvalState & state)
{
auto evalCache = openEvalCache(state, getLockedFlake());
auto root = evalCache->getRoot();
std::vector<ref<eval_cache::AttrCursor>> res;
Suggestions suggestions;
auto attrPaths = getActualAttrPaths();
for (auto & attrPath : attrPaths) {
debug("trying flake output attribute '%s'", attrPath);
auto attr = root->findAlongAttrPath(parseAttrPath(state, attrPath));
if (attr) {
res.push_back(ref(*attr));
} else {
suggestions += attr.getSuggestions();
}
}
if (res.size() == 0)
throw Error(
suggestions,
"flake '%s' does not provide attribute %s",
flakeRef,
showAttrPaths(attrPaths));
return res;
}
std::shared_ptr<flake::LockedFlake> InstallableFlake::getLockedFlake() const
{
if (!_lockedFlake) {
flake::LockFlags lockFlagsApplyConfig = lockFlags;
// FIXME why this side effect?
lockFlagsApplyConfig.applyNixConfig = true;
_lockedFlake = std::make_shared<flake::LockedFlake>(lockFlake(*state, flakeRef, lockFlagsApplyConfig));
}
return _lockedFlake;
}
FlakeRef InstallableFlake::nixpkgsFlakeRef() const
{
auto lockedFlake = getLockedFlake();
if (auto nixpkgsInput = lockedFlake->lockFile.findInput({"nixpkgs"})) {
if (auto lockedNode = std::dynamic_pointer_cast<const flake::LockedNode>(nixpkgsInput)) {
debug("using nixpkgs flake '%s'", lockedNode->lockedRef);
return std::move(lockedNode->lockedRef);
}
}
return defaultNixpkgsFlakeRef();
}
}