From 205dcd140d46db94481329578b4fee8275e6c534 Mon Sep 17 00:00:00 2001
From: Carlo Nucera <carlo.nucera@protonmail.com>
Date: Fri, 17 Jul 2020 12:43:46 -0400
Subject: [PATCH] Revert "Don't anticipate multiple CA outputs for now"

This reverts commit 74b251b2f3d6414de051c8523011c0ee3c5ea154.
---
 src/libstore/local-store.cc | 43 ++++++++++++++++++++++++-------------
 1 file changed, 28 insertions(+), 15 deletions(-)

diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index 19537b8e5..9117ff384 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -544,11 +544,8 @@ void LocalStore::checkDerivationOutputs(const StorePath & drvPath, const Derivat
     std::string drvName(drvPath.name());
     drvName = string(drvName, 0, drvName.size() - drvExtension.size());
 
-    auto check = [&](const StorePath & expected, const StorePath & actual, const std::string & varName)
+    auto envHasRightPath = [&](const StorePath & actual, const std::string & varName)
     {
-        if (actual != expected)
-            throw Error("derivation '%s' has incorrect output '%s', should be '%s'",
-                printStorePath(drvPath), printStorePath(actual), printStorePath(expected));
         auto j = drv.env.find(varName);
         if (j == drv.env.end() || parseStorePath(j->second) != actual)
             throw Error("derivation '%s' has incorrect environment variable '%s', should be '%s'",
@@ -556,18 +553,34 @@ void LocalStore::checkDerivationOutputs(const StorePath & drvPath, const Derivat
     };
 
 
-    if (derivationIsFixed(drv.type())) {
-        DerivationOutputs::const_iterator out = drv.outputs.find("out");
-        if (out == drv.outputs.end())
-            throw Error("derivation '%s' does not have an output named 'out'", printStorePath(drvPath));
-    }
+    // Don't need the answer, but do this anyways to assert is proper
+    // combination. The code below is more general and naturally allows
+    // combinations that are currently prohibited.
+    drv.type();
 
-    else {
-        // Regular, non-CA derivation should always return a single hash and not
-        // hash per output.
-        Hash h = std::get<0>(hashDerivationModulo(*this, drv, true));
-        for (auto & i : drv.outputs)
-            check(makeOutputPath(i.first, h, drvName), i.second.path(*this, drv.name), i.first);
+    std::optional<Hash> h;
+    for (auto & i : drv.outputs) {
+        std::visit(overloaded {
+            [&](DerivationOutputInputAddressed doia) {
+                if (!h) {
+                    // somewhat expensive so we do lazily
+                    auto temp = hashDerivationModulo(*this, drv, true);
+                    h = std::get<Hash>(temp);
+                }
+                StorePath recomputed = makeOutputPath(i.first, *h, drvName);
+                if (doia.path != recomputed)
+                    throw Error("derivation '%s' has incorrect output '%s', should be '%s'",
+                        printStorePath(drvPath), printStorePath(doia.path), printStorePath(recomputed));
+                envHasRightPath(doia.path, i.first);
+            },
+            [&](DerivationOutputFixed dof) {
+                StorePath path = makeFixedOutputPath(dof.hash.method, dof.hash.hash, drvName);
+                envHasRightPath(path, i.first);
+            },
+            [&](DerivationOutputFloating _) {
+                throw Error("Floating CA output derivations are not yet implemented");
+            },
+        }, i.second.output);
     }
 }