From fad244725fe00fc8e4c05b35ae03316e4a2bca5c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Thalheim?= <joerg@thalheim.io>
Date: Sun, 10 Dec 2023 09:17:51 +0100
Subject: [PATCH] print which derivation failed to evaluate

---
 src/nix-eval-jobs.cc | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/nix-eval-jobs.cc b/src/nix-eval-jobs.cc
index ec5ff34..56b6c49 100644
--- a/src/nix-eval-jobs.cc
+++ b/src/nix-eval-jobs.cc
@@ -203,7 +203,7 @@ struct Drv {
     std::map<std::string, std::set<std::string>> inputDrvs;
     std::optional<nlohmann::json> meta;
 
-    Drv(EvalState &state, DrvInfo &drvInfo) {
+    Drv(std::string &attrPath, EvalState &state, DrvInfo &drvInfo) {
 
         auto localStore = state.store.dynamic_pointer_cast<LocalFSStore>();
 
@@ -214,7 +214,8 @@ struct Drv {
                         localStore->printStorePath(*out.second);
             }
         } catch (const std::exception &e) {
-            throw EvalError("derivation must have valid outputs: %s", e.what());
+            throw EvalError("derivation '%s' does not have valid outputs: %s",
+                            attrPath, e.what());
         }
 
         if (myArgs.meta) {
@@ -326,7 +327,7 @@ static void worker(ref<EvalState> state, Bindings &autoArgs, AutoCloseFD &to,
 
             if (v->type() == nAttrs) {
                 if (auto drvInfo = getDerivation(*state, *v, false)) {
-                    auto drv = Drv(*state, *drvInfo);
+                    auto drv = Drv(attrPathS, *state, *drvInfo);
                     reply.update(drv);
 
                     /* Register the derivation as a GC root.  !!! This