From e9fad3006b0b6f3a6430fdbfc61392cac6834502 Mon Sep 17 00:00:00 2001 From: John Ericson Date: Fri, 4 Sep 2020 15:15:51 +0000 Subject: [PATCH] Fix some of the issues raised by @edolstra - More and better comments - The easier renames --- src/libstore/build.cc | 25 +++++++++++++------------ src/libstore/derivations.hh | 18 ++++++++++++++++++ src/libstore/local-store.hh | 5 ++--- src/nix/command.cc | 5 +++-- 4 files changed, 36 insertions(+), 17 deletions(-) diff --git a/src/libstore/build.cc b/src/libstore/build.cc index 5584249d2..9eff03f7b 100644 --- a/src/libstore/build.cc +++ b/src/libstore/build.cc @@ -718,7 +718,7 @@ typedef enum {rpAccept, rpDecline, rpPostpone} HookReply; class SubstitutionGoal; -struct KnownInitialOutputStatus { +struct InitialOutputStatus { StorePath path; /* The output optional indicates whether it's already valid; i.e. exists and is registered. If we're repairing, inner bool indicates whether the @@ -731,9 +731,9 @@ struct KnownInitialOutputStatus { } }; -struct InitialOutputStatus { +struct InitialOutput { bool wanted; - std::optional known; + std::optional known; }; class DerivationGoal : public Goal @@ -770,7 +770,7 @@ private: immediate input paths). */ StorePathSet inputPaths; - std::map initialOutputs; + std::map initialOutputs; /* User selected for running the builder. */ std::unique_ptr buildUser; @@ -1050,11 +1050,14 @@ private: /* Forcibly kill the child process, if any. */ void killChild(); - /* Map a path to another (reproducably) so we can avoid overwriting outputs + /* Create alternative path calculated from but distinct from the + input, so we can avoid overwriting outputs (or other store paths) that already exist. */ StorePath makeFallbackPath(const StorePath & path); - /* Make a path to another based on the output name alone, if one doesn't - want to use a random path for CA builds. */ + /* Make a path to another based on the output name along with the + derivation hash. */ + /* FIXME add option to randomize, so we can audit whether our + rewrites caught everything */ StorePath makeFallbackPath(std::string_view outputName); void repairClosure(); @@ -2141,8 +2144,6 @@ void DerivationGoal::startBuilder() with the actual hashes. */ auto scratchPath = !status.known - /* FIXME add option to randomize, so we can audit whether our - * rewrites caught everything */ ? makeFallbackPath(outputName) : !needsHashRewrite() /* Can always use original path in sandbox */ @@ -4582,19 +4583,19 @@ void DerivationGoal::checkPathValidity() { bool checkHash = buildMode == bmRepair; for (auto & i : queryPartialDerivationOutputMap()) { - InitialOutputStatus status { + InitialOutput info { .wanted = wantOutput(i.first, wantedOutputs), }; if (i.second) { auto outputPath = *i.second; - status.known = { + info.known = { .path = outputPath, .valid = !worker.store.isValidPath(outputPath) ? std::optional {} : !checkHash || worker.pathContentsGood(outputPath), }; } - initialOutputs.insert_or_assign(i.first, status); + initialOutputs.insert_or_assign(i.first, info); } } diff --git a/src/libstore/derivations.hh b/src/libstore/derivations.hh index c5c6e90ca..2c0b1feab 100644 --- a/src/libstore/derivations.hh +++ b/src/libstore/derivations.hh @@ -145,6 +145,11 @@ Derivation parseDerivation(const Store & store, std::string && s, std::string_vi // FIXME: remove bool isDerivation(const string & fileName); +/* Calculate the name that will be used for the store path for this + output. + + This is usually -, but is just when + the output name is "out". */ std::string outputPathName(std::string_view drvName, std::string_view outputName); // known CA drv's output hashes, current just for fixed-output derivations @@ -194,8 +199,21 @@ struct Sink; Source & readDerivation(Source & in, const Store & store, BasicDerivation & drv, std::string_view name); void writeDerivation(Sink & out, const Store & store, const BasicDerivation & drv); +/* This creates an opaque and almost certainly unique string + deterministically from the output name. + + It is used as a placeholder to allow derivations to refer to their + own outputs without needing to use the hash of a derivation in + itself, making the hash near-impossible to calculate. */ std::string hashPlaceholder(const std::string & outputName); +/* This creates an opaque and almost certainly unique string + deterministically from a derivation path and output name. + + It is used as a placeholder to allow derivations to refer to + content-addressed paths whose content --- and thus the path + themselves --- isn't yet known. This occurs when a derivation has a + dependency which is a CA derivation. */ std::string downstreamPlaceholder(const Store & store, const StorePath & drvPath, std::string_view outputName); } diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh index ea430fa14..d5e6d68ef 100644 --- a/src/libstore/local-store.hh +++ b/src/libstore/local-store.hh @@ -279,9 +279,8 @@ private: specified by the ‘secret-key-files’ option. */ void signPathInfo(ValidPathInfo & info); - /* Add a mapping from the deriver of the path info (if specified) to its - * out path - */ + /* Register the store path 'output' as the output named 'outputName' of + derivation 'deriver'. */ void linkDeriverToPath(const StorePath & deriver, const string & outputName, const StorePath & output); void linkDeriverToPath(State & state, uint64_t deriver, const string & outputName, const StorePath & output); diff --git a/src/nix/command.cc b/src/nix/command.cc index f697eb84c..37a4bc785 100644 --- a/src/nix/command.cc +++ b/src/nix/command.cc @@ -150,8 +150,9 @@ void MixProfile::updateProfile(const Buildables & buildables) }, [&](BuildableFromDrv bfd) { for (auto & output : bfd.outputs) { - if (!output.second) - throw Error("output path should be known because we just tried to build it"); + /* Output path should be known because we just tried to + build it. */ + assert(!output.second); result.push_back(*output.second); } },