Add Store::buildPathsWithResults()

This function is like buildPaths(), except that it returns a vector of
BuildResults containing the exact statuses and output paths of each
derivation / substitution. This is convenient for functions like
Installable::build(), because they then don't need to do another
series of calls to get the outputs of CA derivations. It's also a
precondition to impure derivations, where we *can't* query the output
of those derivations since they're not stored in the Nix database.

Note that PathSubstitutionGoal can now also return a BuildStatus.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libstore/build/local-derivation-goal.hh b/src/libstore/build/local-derivation-goal.hh
index 95692c60d..d456e9cae 100644
--- a/src/libstore/build/local-derivation-goal.hh
+++ b/src/libstore/build/local-derivation-goal.hh
@@ -169,7 +169,7 @@ struct LocalDerivationGoal : public DerivationGoal
 
     /* Check that the derivation outputs all exist and register them
        as valid. */
-    void registerOutputs() override;
+    DrvOutputs registerOutputs() override;
 
     void signRealisation(Realisation &) override;