From aad4abcc9c27d5c1a2349e40f51f076387e0f844 Mon Sep 17 00:00:00 2001
From: John Ericson <John.Ericson@Obsidian.Systems>
Date: Fri, 4 Sep 2020 01:17:38 +0000
Subject: [PATCH] Fix floating CA tests

We will sometimes try to query the outputs of derivations we can't
resolve. That's fine; it just means we don't know what those outputs are
yet.
---
 src/libstore/build.cc       | 4 +++-
 src/libstore/derivations.cc | 4 ++--
 src/libstore/derivations.hh | 2 +-
 src/libstore/local-store.cc | 9 +++++++--
 tests/content-addressed.sh  | 2 +-
 5 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 1249668c4..1f77b8ea8 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -1460,7 +1460,9 @@ void DerivationGoal::inputsRealised()
             /* We are be able to resolve this derivation based on the
                now-known results of dependencies. If so, we become a stub goal
                aliasing that resolved derivation goal */
-            Derivation drvResolved { fullDrv.resolve(worker.store) };
+            std::optional attempt = fullDrv.tryResolve(worker.store);
+            assert(attempt);
+            Derivation drvResolved { *std::move(attempt) };
 
             auto pathResolved = writeDerivation(worker.store, drvResolved);
             /* Add to memotable to speed up downstream goal's queries with the
diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc
index ce57a5bb0..695265860 100644
--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@@ -671,7 +671,7 @@ static void rewriteDerivation(Store & store, BasicDerivation & drv, const String
 
 Sync<DrvPathResolutions> drvPathResolutions;
 
-BasicDerivation Derivation::resolve(Store & store) {
+std::optional<BasicDerivation> Derivation::tryResolve(Store & store) {
     BasicDerivation resolved { *this };
 
     // Input paths that we'll want to rewrite in the derivation
@@ -683,7 +683,7 @@ BasicDerivation Derivation::resolve(Store & store) {
         for (auto & outputName : input.second) {
             auto actualPathOpt = inputDrvOutputs.at(outputName);
             if (!actualPathOpt)
-                throw Error("input drv '%s' wasn't yet built", store.printStorePath(input.first));
+                return std::nullopt;
             auto actualPath = *actualPathOpt;
             inputRewrites.emplace(
                 downstreamPlaceholder(store, input.first, outputName),
diff --git a/src/libstore/derivations.hh b/src/libstore/derivations.hh
index e4d85aa05..eaffbf452 100644
--- a/src/libstore/derivations.hh
+++ b/src/libstore/derivations.hh
@@ -133,7 +133,7 @@ struct Derivation : BasicDerivation
        1. input drv outputs moved to input sources.
 
        2. placeholders replaced with realized input store paths. */
-    BasicDerivation resolve(Store & store);
+    std::optional<BasicDerivation> tryResolve(Store & store);
 
     Derivation() = default;
     Derivation(BasicDerivation && bd) : BasicDerivation(std::move(bd)) { }
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index e51d127b3..f490188ce 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -825,8 +825,13 @@ std::map<std::string, std::optional<StorePath>> LocalStore::queryPartialDerivati
     /* can't just use else-if instead of `!haveCached` because we need to unlock
        `drvPathResolutions` before it is locked in `Derivation::resolve`. */
     if (!haveCached && drv.type() == DerivationType::CAFloating) {
-        /* Resolve drv and use that path instead. */
-        auto pathResolved = writeDerivation(*this, drv.resolve(*this));
+        /* Try resolve drv and use that path instead. */
+        auto attempt = drv.tryResolve(*this);
+        if (!attempt)
+            /* If we cannot resolve the derivation, we cannot have any path
+               assigned so we return the map of all std::nullopts. */
+            return outputs;
+        auto pathResolved = writeDerivation(*this, *std::move(attempt));
         /* Store in memo table. */
         /* FIXME: memo logic should not be local-store specific, should have
            wrapper-method instead. */
diff --git a/tests/content-addressed.sh b/tests/content-addressed.sh
index b2e94fe1e..34334b22d 100644
--- a/tests/content-addressed.sh
+++ b/tests/content-addressed.sh
@@ -9,7 +9,7 @@ testDerivation () {
     local derivationPath=$1
     local commonArgs=("--experimental-features" "ca-derivations" "./content-addressed.nix" "-A" "$derivationPath" "--no-out-link")
     local out1 out2
-    out1=$(set -e; nix-build "${commonArgs[@]}" --arg seed 1)
+    out1=$(nix-build "${commonArgs[@]}" --arg seed 1)
     out2=$(nix-build "${commonArgs[@]}" --arg seed 2 "${secondSeedArgs[@]}")
     test "$out1" == "$out2"
 }