diff options
Diffstat (limited to 'src/libexpr')
| -rw-r--r-- | src/libexpr/primops/fetchClosure.cc | 42 |
1 files changed, 34 insertions, 8 deletions
diff --git a/src/libexpr/primops/fetchClosure.cc b/src/libexpr/primops/fetchClosure.cc index 96c1df544..c66fed633 100644 --- a/src/libexpr/primops/fetchClosure.cc +++ b/src/libexpr/primops/fetchClosure.cc @@ -13,7 +13,7 @@ static void prim_fetchClosure(EvalState & state, const PosIdx pos, Value * * arg std::optional<StorePath> fromPath; bool enableRewriting = false; std::optional<StorePath> toPath; - bool inputAddressed = false; + std::optional<bool> inputAddressedMaybe; for (auto & attr : *args[0]->attrs) { const auto & attrName = state.symbols[attr.name]; @@ -40,7 +40,7 @@ static void prim_fetchClosure(EvalState & state, const PosIdx pos, Value * * arg attrHint()); else if (attrName == "inputAddressed") - inputAddressed = state.forceBool(*attr.value, attr.pos, attrHint()); + inputAddressedMaybe = state.forceBool(*attr.value, attr.pos, attrHint()); else throw Error({ @@ -55,6 +55,8 @@ static void prim_fetchClosure(EvalState & state, const PosIdx pos, Value * * arg .errPos = state.positions[pos] }); + bool inputAddressed = inputAddressedMaybe.value_or(false); + if (inputAddressed) { if (toPath && toPath != fromPath) throw Error({ @@ -120,15 +122,39 @@ static void prim_fetchClosure(EvalState & state, const PosIdx pos, Value * * arg toPath = fromPath; } - /* We want input addressing to be explicit, to inform readers and to give - expression authors an opportunity to improve their user experience. */ - if (!inputAddressed) { - auto info = state.store->queryPathInfo(*toPath); + auto info = state.store->queryPathInfo(*toPath); + + /* If inputAddressed is set, make sure the result is as expected. */ + if (inputAddressedMaybe) { + bool expectCA = !inputAddressed; + if (info->isContentAddressed(*state.store) != expectCA) { + if (inputAddressed) + throw Error({ + .msg = hintfmt("The 'fetchClosure' result, '%s' is not input addressed, despite 'inputAddressed' being set to true. It is ok or even preferable to return a content addressed path, so you probably want to remove the 'inputAddressed' attribute", + state.store->printStorePath(*toPath)), + .errPos = state.positions[pos] + }); + else + throw Error({ + .msg = hintfmt("The 'fetchClosure' result, '%s' is input addressed, despite 'inputAddressed' being set to false. Please make sure you passed the correct path(s) or set 'inputAddressed' to true if you intended to return an input addressed path", + state.store->printStorePath(*toPath)), + .errPos = state.positions[pos] + }); + } + } else { + /* + While it's fine to omit the inputAddressed attribute for CA paths, + we want input addressing to be explicit, to inform readers and to give + expression authors an opportunity to improve their user experience; + see message below. + */ if (!info->isContentAddressed(*state.store)) { if (enableRewriting) { + // We don't perform the rewriting when outPath already exists, as an optimisation. + // However, we can quickly detect a mistake if the toPath is input addressed. + // Ideally we'd compute the path for them here, but this error message is unlikely to occur in practice, so we keep it simple. throw Error({ - // Ideally we'd compute the path for them, but this error message is unlikely to occur in practice, so we keep it simple. - .msg = hintfmt("Rewriting was requested, but 'toPath' is not content addressed. This is impossible. Please change 'toPath' to the correct path, or to a non-existing path, and try again", + .msg = hintfmt("The 'toPath' value '%s' is input addressed, so it can't possibly be the result of rewriting. You may set 'toPath' to an empty string to figure out the correct path.", state.store->printStorePath(*toPath)), .errPos = state.positions[pos] }); |