From 31f1af0cabb65e3c5f8f4539500c6b236c387780 Mon Sep 17 00:00:00 2001
From: Ben Burdette <bburdette@gmail.com>
Date: Wed, 5 Aug 2020 11:26:06 -0600
Subject: [PATCH] don't crash if there's no drvPath

---
 src/build-remote/build-remote.cc | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/build-remote/build-remote.cc b/src/build-remote/build-remote.cc
index 723e1463e..5247cefa6 100644
--- a/src/build-remote/build-remote.cc
+++ b/src/build-remote/build-remote.cc
@@ -181,9 +181,15 @@ static int _main(int argc, char * * argv)
                         }
 
                         // add the template values.
+                        string drvstr;
+                        if (drvPath.has_value())
+                            drvstr = drvPath->to_string();
+                        else
+                            drvstr = "<unknown>";
+
                         auto hint = hintformat(hintstring);
                         hint
-                          % drvPath->to_string()
+                          % drvstr
                           % neededSystem
                           % concatStringsSep<StringSet>(", ", requiredFeatures)
                           % machines.size();