Only provide builtin.{getFlake,fetchClosure} is the corresponding experimental feature is enabled

This allows writing fallback code like

  if builtins ? fetchClosure then
    builtins.fetchClose { ... }
  else
    builtins.storePath ...
This commit is contained in:
Eelco Dolstra 2022-03-25 14:04:18 +01:00
parent 55bc524019
commit 86b05ccd54
8 changed files with 31 additions and 39 deletions

View file

@ -5,9 +5,12 @@
* `nix store make-content-addressable` has been renamed to `nix store
make-content-addressed`.
* New builtin function `builtins.fetchClosure` that copies a closure
from a binary cache at evaluation time and rewrites it to
content-addressed form (if it isn't already). Like
* New experimental builtin function `builtins.fetchClosure` that
copies a closure from a binary cache at evaluation time and rewrites
it to content-addressed form (if it isn't already). Like
`builtins.storePath`, this allows importing pre-built store paths;
the difference is that it doesn't require the user to configure
binary caches and trusted public keys.
This function is only available if you enable the experimental
feature `fetch-closure`.

View file

@ -507,23 +507,6 @@ EvalState::~EvalState()
}
void EvalState::requireExperimentalFeatureOnEvaluation(
const ExperimentalFeature & feature,
const std::string_view fName,
const Pos & pos)
{
if (!settings.isExperimentalFeatureEnabled(feature)) {
throw EvalError({
.msg = hintfmt(
"Cannot call '%2%' because experimental Nix feature '%1%' is disabled. You can enable it via '--extra-experimental-features %1%'.",
feature,
fName
),
.errPos = pos
});
}
}
void EvalState::allowPath(const Path & path)
{
if (allowedPaths)

View file

@ -149,12 +149,6 @@ public:
std::shared_ptr<Store> buildStore = nullptr);
~EvalState();
void requireExperimentalFeatureOnEvaluation(
const ExperimentalFeature &,
const std::string_view fName,
const Pos & pos
);
void addToSearchPath(const std::string & s);
SearchPath getSearchPath() { return searchPath; }

View file

@ -706,8 +706,6 @@ void callFlake(EvalState & state,
static void prim_getFlake(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
state.requireExperimentalFeatureOnEvaluation(Xp::Flakes, "builtins.getFlake", pos);
std::string flakeRefS(state.forceStringNoCtx(*args[0], pos));
auto flakeRef = parseFlakeRef(flakeRefS, {}, true);
if (evalSettings.pureEval && !flakeRef.input.isLocked())
@ -723,7 +721,12 @@ static void prim_getFlake(EvalState & state, const Pos & pos, Value * * args, Va
v);
}
static RegisterPrimOp r2("__getFlake", 1, prim_getFlake);
static RegisterPrimOp r2({
.name = "__getFlake",
.args = {"args"},
.fun = prim_getFlake,
.experimentalFeature = Xp::Flakes,
});
}

View file

@ -3814,7 +3814,7 @@ RegisterPrimOp::RegisterPrimOp(std::string name, size_t arity, PrimOpFun fun)
.name = name,
.args = {},
.arity = arity,
.fun = fun
.fun = fun,
});
}
@ -3886,6 +3886,9 @@ void EvalState::createBaseEnv()
if (RegisterPrimOp::primOps)
for (auto & primOp : *RegisterPrimOp::primOps)
if (!primOp.experimentalFeature
|| settings.isExperimentalFeatureEnabled(*primOp.experimentalFeature))
{
addPrimOp({
.fun = primOp.fun,
.arity = std::max(primOp.args.size(), primOp.arity),
@ -3893,6 +3896,7 @@ void EvalState::createBaseEnv()
.args = primOp.args,
.doc = primOp.doc,
});
}
/* Add a wrapper around the derivation primop that computes the
`drvPath' and `outPath' attributes lazily. */

View file

@ -16,6 +16,7 @@ struct RegisterPrimOp
size_t arity = 0;
const char * doc;
PrimOpFun fun;
std::optional<ExperimentalFeature> experimentalFeature;
};
typedef std::vector<Info> PrimOps;
@ -35,6 +36,7 @@ struct RegisterPrimOp
/* These primops are disabled without enableNativeCode, but plugins
may wish to use them in limited contexts without globally enabling
them. */
/* Load a ValueInitializer from a DSO and return whatever it initializes */
void prim_importNative(EvalState & state, const Pos & pos, Value * * args, Value & v);

View file

@ -7,8 +7,6 @@ namespace nix {
static void prim_fetchClosure(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
settings.requireExperimentalFeature(Xp::FetchClosure);
state.forceAttrs(*args[0], pos);
std::optional<std::string> fromStoreUrl;
@ -145,8 +143,12 @@ static RegisterPrimOp primop_fetchClosure({
specifying a binary cache from which the path can be fetched.
Also, requiring a content-addressed final store path avoids the
need for users to configure binary cache public keys.
This function is only available if you enable the experimental
feature `fetch-closure`.
)",
.fun = prim_fetchClosure,
.experimentalFeature = Xp::FetchClosure,
});
}

View file

@ -289,6 +289,7 @@ void mainWrapped(int argc, char * * argv)
}
if (argc == 2 && std::string(argv[1]) == "__dump-builtins") {
settings.experimentalFeatures = {Xp::Flakes, Xp::FetchClosure};
evalSettings.pureEval = false;
EvalState state({}, openStore("dummy://"));
auto res = nlohmann::json::object();