From 1b1f557d888fa84b1bc818f1b221776355a7a2dd Mon Sep 17 00:00:00 2001
From: Tobias Geerinckx-Rice <me@tobias.gr>
Date: Fri, 19 Nov 2021 17:37:44 +0100
Subject: [PATCH] daemon: Print the line whence we expect an integer.

* nix/libstore/local-store.cc (LocalStore::getLineFromSubstituter):
Include the malformed substituter stream line in the error message.
---
 nix/libstore/local-store.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/nix/libstore/local-store.cc b/nix/libstore/local-store.cc
index d52b102343..0883a4bbce 100644
--- a/nix/libstore/local-store.cc
+++ b/nix/libstore/local-store.cc
@@ -839,7 +839,8 @@ template<class T> T LocalStore::getIntLineFromSubstituter(Agent & run)
 {
     string s = getLineFromSubstituter(run);
     T res;
-    if (!string2Int(s, res)) throw Error("integer expected from stream");
+    if (!string2Int(s, res))
+        throw Error(format("integer expected from stream: %1%") % s);
     return res;
 }