From 644415d3912633773d2c8f219572fbfa452f4b56 Mon Sep 17 00:00:00 2001
From: Maximilian Bosch <maximilian@mbosch.me>
Date: Thu, 24 Jun 2021 15:06:07 +0200
Subject: [PATCH] Perform input rewrites only in LocalDerivationGoal

---
 src/libstore/build/local-derivation-goal.cc | 11 ++++++++++-
 src/libstore/parsed-derivations.cc          | 11 ++---------
 src/libstore/parsed-derivations.hh          |  2 +-
 src/nix-build/nix-build.cc                  |  2 +-
 4 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 15a7cb4ac..259134eba 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -1086,8 +1086,17 @@ void LocalDerivationGoal::initEnv()
 
 void LocalDerivationGoal::writeStructuredAttrs()
 {
-    if (auto structAttrsJson = parsedDrv->prepareStructuredAttrs(inputRewrites, worker.store, inputPaths)) {
+    if (auto structAttrsJson = parsedDrv->prepareStructuredAttrs(worker.store, inputPaths)) {
         auto json = structAttrsJson.value();
+        nlohmann::json rewritten;
+        for (auto & [i, v] : json["outputs"].get<nlohmann::json::object_t>()) {
+            /* The placeholder must have a rewrite, so we use it to cover both the
+               cases where we know or don't know the output path ahead of time. */
+            rewritten[i] = rewriteStrings(v, inputRewrites);
+        }
+
+        json["outputs"] = rewritten;
+
         auto jsonSh = writeStructuredAttrsShell(json);
 
         writeFile(tmpDir + "/.attrs.sh", rewriteStrings(jsonSh, inputRewrites));
diff --git a/src/libstore/parsed-derivations.cc b/src/libstore/parsed-derivations.cc
index f021e4de3..ee6bbb045 100644
--- a/src/libstore/parsed-derivations.cc
+++ b/src/libstore/parsed-derivations.cc
@@ -124,7 +124,7 @@ bool ParsedDerivation::substitutesAllowed() const
 }
 
 static std::regex shVarName("[A-Za-z_][A-Za-z0-9_]*");
-std::optional<nlohmann::json> ParsedDerivation::prepareStructuredAttrs(std::optional<StringMap> inputRewrites, Store & store, const StorePathSet & inputPaths)
+std::optional<nlohmann::json> ParsedDerivation::prepareStructuredAttrs(Store & store, const StorePathSet & inputPaths)
 {
     auto structuredAttrs = getStructuredAttrs();
     if (!structuredAttrs) return std::nullopt;
@@ -134,14 +134,7 @@ std::optional<nlohmann::json> ParsedDerivation::prepareStructuredAttrs(std::opti
     /* Add an "outputs" object containing the output paths. */
     nlohmann::json outputs;
     for (auto & i : drv.outputs) {
-        if (inputRewrites) {
-            /* The placeholder must have a rewrite, so we use it to cover both the
-               cases where we know or don't know the output path ahead of time. */
-            outputs[i.first] = rewriteStrings(hashPlaceholder(i.first), inputRewrites.value());
-        } else {
-            /* This case is only relevant for the nix-shell */
-            outputs[i.first] = hashPlaceholder(i.first);
-        }
+        outputs[i.first] = hashPlaceholder(i.first);
     }
     json["outputs"] = outputs;
 
diff --git a/src/libstore/parsed-derivations.hh b/src/libstore/parsed-derivations.hh
index 8061e3a8b..5e3fb93ca 100644
--- a/src/libstore/parsed-derivations.hh
+++ b/src/libstore/parsed-derivations.hh
@@ -37,7 +37,7 @@ public:
 
     bool substitutesAllowed() const;
 
-    std::optional<nlohmann::json> prepareStructuredAttrs(std::optional<StringMap> inputRewrites, Store & store, const StorePathSet & inputPaths);
+    std::optional<nlohmann::json> prepareStructuredAttrs(Store & store, const StorePathSet & inputPaths);
 };
 
 std::string writeStructuredAttrsShell(nlohmann::json & json);
diff --git a/src/nix-build/nix-build.cc b/src/nix-build/nix-build.cc
index 459876465..519cbd5bb 100755
--- a/src/nix-build/nix-build.cc
+++ b/src/nix-build/nix-build.cc
@@ -444,7 +444,7 @@ static void main_nix_build(int argc, char * * argv)
                 drv
             );
 
-            if (auto structAttrs = parsedDrv.prepareStructuredAttrs(std::nullopt, *store, inputs)) {
+            if (auto structAttrs = parsedDrv.prepareStructuredAttrs(*store, inputs)) {
                 auto json = structAttrs.value();
                 structuredAttrsRC = writeStructuredAttrsShell(json);