diff options
| -rw-r--r-- | doc/manual/src/language/advanced-attributes.md | 6 | ||||
| -rw-r--r-- | doc/manual/src/release-notes/rl-next.md | 12 | ||||
| -rw-r--r-- | src/libstore/build/local-derivation-goal.cc | 25 | ||||
| -rw-r--r-- | src/libutil/experimental-features.cc | 1 | ||||
| -rw-r--r-- | src/libutil/experimental-features.hh | 1 | ||||
| -rw-r--r-- | tests/check-refs.nix | 7 | ||||
| -rw-r--r-- | tests/check-refs.sh | 9 |
7 files changed, 54 insertions, 7 deletions
diff --git a/doc/manual/src/language/advanced-attributes.md b/doc/manual/src/language/advanced-attributes.md index 2e7e80ed0..f02425b13 100644 --- a/doc/manual/src/language/advanced-attributes.md +++ b/doc/manual/src/language/advanced-attributes.md @@ -207,13 +207,13 @@ Derivations can declare some infrequently used optional attributes. the hash in either hexadecimal or base-32 notation. (See the [`nix-hash` command](../command-ref/nix-hash.md) for information about converting to and from base-32 notation.) - + - [`__contentAddressed`]{#adv-attr-__contentAddressed} If this **experimental** attribute is set to true, then the derivation outputs will be stored in a content-addressed location rather than the traditional input-addressed one. - This only has an effect if the `ca-derivation` experimental feature is enabled. - + This only has an effect if the `ca-derivations` experimental feature is enabled. + Setting this attribute also requires setting `outputHashMode` and `outputHashAlgo` like for *fixed-output derivations* (see above). - [`passAsFile`]{#adv-attr-passAsFile}\ diff --git a/doc/manual/src/release-notes/rl-next.md b/doc/manual/src/release-notes/rl-next.md index 8a79703ab..7e8344e63 100644 --- a/doc/manual/src/release-notes/rl-next.md +++ b/doc/manual/src/release-notes/rl-next.md @@ -8,3 +8,15 @@ discovered by making multiple syscalls. This change makes these operations lazy such that these lookups will only be performed if the attribute is used. This optimization affects a minority of filesystems and operating systems. + +* In derivations that use structured attributes, you can now use `unsafeDiscardReferences` + to disable scanning a given output for runtime dependencies: + ```nix + __structuredAttrs = true; + unsafeDiscardReferences.out = true; + ``` + This is useful e.g. when generating self-contained filesystem images with + their own embedded Nix store: hashes found inside such an image refer + to the embedded store and not to the host's Nix store. + + This requires the `discard-references` experimental feature. diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc index 9ab9b17fe..2b85b20d1 100644 --- a/src/libstore/build/local-derivation-goal.cc +++ b/src/libstore/build/local-derivation-goal.cc @@ -2323,11 +2323,28 @@ DrvOutputs LocalDerivationGoal::registerOutputs() buildUser ? std::optional(buildUser->getUIDRange()) : std::nullopt, inodesSeen); - debug("scanning for references for output '%s' in temp location '%s'", outputName, actualPath); + bool discardReferences = false; + if (auto structuredAttrs = parsedDrv->getStructuredAttrs()) { + if (auto udr = get(*structuredAttrs, "unsafeDiscardReferences")) { + settings.requireExperimentalFeature(Xp::DiscardReferences); + if (auto output = get(*udr, outputName)) { + if (!output->is_boolean()) + throw Error("attribute 'unsafeDiscardReferences.\"%s\"' of derivation '%s' must be a Boolean", outputName, drvPath.to_string()); + discardReferences = output->get<bool>(); + } + } + } - /* Pass blank Sink as we are not ready to hash data at this stage. */ - NullSink blank; - auto references = scanForReferences(blank, actualPath, referenceablePaths); + StorePathSet references; + if (discardReferences) + debug("discarding references of output '%s'", outputName); + else { + debug("scanning for references for output '%s' in temp location '%s'", outputName, actualPath); + + /* Pass blank Sink as we are not ready to hash data at this stage. */ + NullSink blank; + references = scanForReferences(blank, actualPath, referenceablePaths); + } outputReferencesIfUnregistered.insert_or_assign( outputName, diff --git a/src/libutil/experimental-features.cc b/src/libutil/experimental-features.cc index e0902971e..58d762ebb 100644 --- a/src/libutil/experimental-features.cc +++ b/src/libutil/experimental-features.cc @@ -16,6 +16,7 @@ std::map<ExperimentalFeature, std::string> stringifiedXpFeatures = { { Xp::ReplFlake, "repl-flake" }, { Xp::AutoAllocateUids, "auto-allocate-uids" }, { Xp::Cgroups, "cgroups" }, + { Xp::DiscardReferences, "discard-references" }, }; const std::optional<ExperimentalFeature> parseExperimentalFeature(const std::string_view & name) diff --git a/src/libutil/experimental-features.hh b/src/libutil/experimental-features.hh index af775feb0..ac372e03e 100644 --- a/src/libutil/experimental-features.hh +++ b/src/libutil/experimental-features.hh @@ -25,6 +25,7 @@ enum struct ExperimentalFeature ReplFlake, AutoAllocateUids, Cgroups, + DiscardReferences, }; /** diff --git a/tests/check-refs.nix b/tests/check-refs.nix index 9d90b0920..99d69a226 100644 --- a/tests/check-refs.nix +++ b/tests/check-refs.nix @@ -67,4 +67,11 @@ rec { disallowedReferences = [test5]; }; + test11 = makeTest 11 { + __structuredAttrs = true; + unsafeDiscardReferences.out = true; + outputChecks.out.allowedReferences = []; + buildCommand = ''echo ${dep} > "''${outputs[out]}"''; + }; + } diff --git a/tests/check-refs.sh b/tests/check-refs.sh index 16bbabc40..65a72552a 100644 --- a/tests/check-refs.sh +++ b/tests/check-refs.sh @@ -40,3 +40,12 @@ nix-build -o $RESULT check-refs.nix -A test7 # test10 should succeed (no disallowed references). nix-build -o $RESULT check-refs.nix -A test10 + +if isDaemonNewer 2.12pre20230103; then + enableFeatures discard-references + restartDaemon + + # test11 should succeed. + test11=$(nix-build -o $RESULT check-refs.nix -A test11) + [[ -z $(nix-store -q --references "$test11") ]] +fi |