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mirror of https://github.com/NixOS/nix synced 2025-06-28 05:21:16 +02:00

Never update values after setting the type

Thunks are now overwritten by a helper function
`Value::finishValue(newType, payload)` (where `payload` is the
original anonymous union inside `Value`). This helps to ensure we
never update a value elsewhere, since that would be incompatible with
parallel evaluation (i.e. after a value has transitioned from being a
thunk to being a non-thunk, it should be immutable).

There were two places where this happened: `Value::mkString()` and
`ExprAttrs::eval()`.

This PR also adds a bunch of accessor functions for value contents,
like `Value::integer()` to access the integer field in the union.
This commit is contained in:
Eelco Dolstra 2024-03-25 18:20:18 +01:00
parent 6d90287f5a
commit 8c0590fa32
35 changed files with 530 additions and 556 deletions

View file

@ -258,7 +258,7 @@ static void prim_appendContext(EvalState & state, const PosIdx pos, Value * * ar
auto sPath = state.symbols.create("path");
auto sAllOutputs = state.symbols.create("allOutputs");
for (auto & i : *args[1]->attrs) {
for (auto & i : *args[1]->attrs()) {
const auto & name = state.symbols[i.name];
if (!state.store->isStorePath(name))
state.error<EvalError>(
@ -269,17 +269,16 @@ static void prim_appendContext(EvalState & state, const PosIdx pos, Value * * ar
if (!settings.readOnlyMode)
state.store->ensurePath(namePath);
state.forceAttrs(*i.value, i.pos, "while evaluating the value of a string context");
auto iter = i.value->attrs->find(sPath);
if (iter != i.value->attrs->end()) {
if (state.forceBool(*iter->value, iter->pos, "while evaluating the `path` attribute of a string context"))
if (auto attr = i.value->attrs()->get(sPath)) {
if (state.forceBool(*attr->value, attr->pos, "while evaluating the `path` attribute of a string context"))
context.emplace(NixStringContextElem::Opaque {
.path = namePath,
});
}
iter = i.value->attrs->find(sAllOutputs);
if (iter != i.value->attrs->end()) {
if (state.forceBool(*iter->value, iter->pos, "while evaluating the `allOutputs` attribute of a string context")) {
if (auto attr = i.value->attrs()->get(sAllOutputs)) {
if (state.forceBool(*attr->value, attr->pos, "while evaluating the `allOutputs` attribute of a string context")) {
if (!isDerivation(name)) {
state.error<EvalError>(
"tried to add all-outputs context of %s, which is not a derivation, to a string",
@ -292,17 +291,16 @@ static void prim_appendContext(EvalState & state, const PosIdx pos, Value * * ar
}
}
iter = i.value->attrs->find(state.sOutputs);
if (iter != i.value->attrs->end()) {
state.forceList(*iter->value, iter->pos, "while evaluating the `outputs` attribute of a string context");
if (iter->value->listSize() && !isDerivation(name)) {
if (auto attr = i.value->attrs()->get(state.sOutputs)) {
state.forceList(*attr->value, attr->pos, "while evaluating the `outputs` attribute of a string context");
if (attr->value->listSize() && !isDerivation(name)) {
state.error<EvalError>(
"tried to add derivation output context of %s, which is not a derivation, to a string",
name
).atPos(i.pos).debugThrow();
}
for (auto elem : iter->value->listItems()) {
auto outputName = state.forceStringNoCtx(*elem, iter->pos, "while evaluating an output name within a string context");
for (auto elem : attr->value->listItems()) {
auto outputName = state.forceStringNoCtx(*elem, attr->pos, "while evaluating an output name within a string context");
context.emplace(NixStringContextElem::Built {
.drvPath = makeConstantStorePathRef(namePath),
.output = std::string { outputName },