From 97e01107ecf4d5cea97bd20423409ba2a112612c Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Sun, 14 Jul 2024 11:51:53 +0200
Subject: [PATCH] dropEmptyInitThenConcatStringsSep -> concatStringSep: empty
 separator

When the separator is empty, no difference is observable.

Note that concatStringsSep has centralized definitions. This adds the
required definitions. Alternatively, `strings-inline.hh` could be
included at call sites.
---
 src/libutil/strings.cc | 7 +++++++
 src/libutil/util.hh    | 4 +++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/libutil/strings.cc b/src/libutil/strings.cc
index 15937d415..7ec618bf4 100644
--- a/src/libutil/strings.cc
+++ b/src/libutil/strings.cc
@@ -9,4 +9,11 @@ template std::string concatStringsSep(std::string_view, const Strings &);
 template std::string concatStringsSep(std::string_view, const StringSet &);
 template std::string concatStringsSep(std::string_view, const std::vector<std::string> &);
 
+typedef std::string_view strings_2[2];
+template std::string concatStringsSep(std::string_view, const strings_2 &);
+typedef std::string_view strings_3[3];
+template std::string concatStringsSep(std::string_view, const strings_3 &);
+typedef std::string_view strings_4[4];
+template std::string concatStringsSep(std::string_view, const strings_4 &);
+
 } // namespace nix
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 971ecf63b..877d15279 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -11,6 +11,8 @@
 #include <sstream>
 #include <optional>
 
+#include "strings.hh"
+
 namespace nix {
 
 void initLibUtil();
@@ -69,7 +71,7 @@ auto concatStrings(Parts && ... parts)
     -> std::enable_if_t<(... && std::is_convertible_v<Parts, std::string_view>), std::string>
 {
     std::string_view views[sizeof...(parts)] = { parts... };
-    return dropEmptyInitThenConcatStringsSep({}, views);
+    return concatStringsSep({}, views);
 }