Merge pull request #13858 from obsidiansystems/no-more-defered-exception

Get rid of `delayedException` in `DerivationBuilder`

src/libstore/build/derivation-building-goal.cc

@@ -653,16 +653,6 @@ Goal::Co DerivationBuildingGoal::tryToBuild()
                     goal.worker.childTerminated(&goal);
                 }
 
-                void noteHashMismatch() override
-                {
-                    goal.worker.hashMismatch = true;
-                }
-
-                void noteCheckMismatch() override
-                {
-                    goal.worker.checkMismatch = true;
-                }
-
                 void markContentsGood(const StorePath & path) override
                 {
                     goal.worker.markContentsGood(path);
@@ -770,6 +760,26 @@ Goal::Co DerivationBuildingGoal::tryToBuild()
     // N.B. cannot use `std::visit` with co-routine return
     if (auto * ste = std::get_if<0>(&res)) {
         outputLocks.unlock();
+// Allow selecting a subset of enum values
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wswitch-enum"
+        switch (ste->status) {
+        case BuildResult::HashMismatch:
+            worker.hashMismatch = true;
+            /* See header, the protocols don't know about `HashMismatch`
+               yet, so change it to `OutputRejected`, which they expect
+               for this case (hash mismatch is a type of output
+               rejection). */
+            ste->status = BuildResult::OutputRejected;
+            break;
+        case BuildResult::NotDeterministic:
+            worker.checkMismatch = true;
+            break;
+        default:
+            /* Other statuses need no adjusting */
+            break;
+        }
+#  pragma GCC diagnostic pop
         co_return doneFailure(std::move(*ste));
     } else if (auto * builtOutputs = std::get_if<1>(&res)) {
         StorePathSet outputPaths;

src/libstore/build/derivation-check.cc

@@ -10,6 +10,7 @@ namespace nix {
 void checkOutputs(
     Store & store,
     const StorePath & drvPath,
+    const decltype(Derivation::outputs) & drvOutputs,
     const decltype(DerivationOptions::outputChecks) & outputChecks,
     const std::map<std::string, ValidPathInfo> & outputs)
 {
@@ -17,9 +18,37 @@ void checkOutputs(
     for (auto & output : outputs)
         outputsByPath.emplace(store.printStorePath(output.second.path), output.second);
 
-    for (auto & output : outputs) {
-        auto & outputName = output.first;
-        auto & info = output.second;
+    for (auto & [outputName, info] : outputs) {
+
+        auto * outputSpec = get(drvOutputs, outputName);
+        assert(outputSpec);
+
+        if (const auto * dof = std::get_if<DerivationOutput::CAFixed>(&outputSpec->raw)) {
+            auto & wanted = dof->ca.hash;
+
+            /* Check wanted hash */
+            assert(info.ca);
+            auto & got = info.ca->hash;
+            if (wanted != got) {
+                /* Throw an error after registering the path as
+                   valid. */
+                throw BuildError(
+                    BuildResult::HashMismatch,
+                    "hash mismatch in fixed-output derivation '%s':\n  specified: %s\n     got:    %s",
+                    store.printStorePath(drvPath),
+                    wanted.to_string(HashFormat::SRI, true),
+                    got.to_string(HashFormat::SRI, true));
+            }
+            if (!info.references.empty()) {
+                auto numViolations = info.references.size();
+                throw BuildError(
+                    BuildResult::HashMismatch,
+                    "fixed-output derivations must not reference store paths: '%s' references %d distinct paths, e.g. '%s'",
+                    store.printStorePath(drvPath),
+                    numViolations,
+                    store.printStorePath(*info.references.begin()));
+            }
+        }
 
         /* Compute the closure and closure size of some output. This
            is slightly tricky because some of its references (namely

src/libstore/build/derivation-check.hh

@@ -20,6 +20,7 @@ namespace nix {
 void checkOutputs(
     Store & store,
     const StorePath & drvPath,
+    const decltype(Derivation::outputs) & drvOutputs,
     const decltype(DerivationOptions::outputChecks) & drvOptions,
     const std::map<std::string, ValidPathInfo> & outputs);