From 7bcd39da352533405f73383a61b63acf03299c16 Mon Sep 17 00:00:00 2001
From: Daiderd Jordan <daiderd@gmail.com>
Date: Sat, 2 May 2020 23:26:12 +0200
Subject: [PATCH] logging: handle build log lines in simple logger

The raw stderr output isn't logged anymore so the build logs need to be
printed by the default logger in order for the old commands like
nix-build to still show build output.
---
 src/libutil/logging.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/libutil/logging.cc b/src/libutil/logging.cc
index 3cc4ef8f15b..777650de5cd 100644
--- a/src/libutil/logging.cc
+++ b/src/libutil/logging.cc
@@ -63,6 +63,16 @@ class SimpleLogger : public Logger
         writeToStderr(prefix + filterANSIEscapes(fs.s, !tty) + "\n");
     }
 
+    void result(ActivityId act, ResultType type, const std::vector<Field> & fields) override
+    {
+        if (type == resBuildLogLine || type == resPostBuildLogLine) {
+            assert(0 < fields.size());
+            assert(fields[0].type == Logger::Field::tString);
+            auto lastLine = fields[0].s;
+            log(lvlInfo, lastLine);
+        }
+    }
+
     void startActivity(ActivityId act, Verbosity lvl, ActivityType type,
         const std::string & s, const Fields & fields, ActivityId parent)
         override