From 4260a22a55d7afc931b22e8c41282fbd0ed18a77 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Wed, 8 Jan 2020 15:34:06 +0100
Subject: [PATCH] absPath(): Use std::optional

(cherry picked from commit 1bf9eb21b75f0d93d9c1633ea2e6fdf840047e79)
---
 src/libutil/util.cc | 6 +++---
 src/libutil/util.hh | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 52a1394f2..097ff210a 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -97,10 +97,10 @@ void replaceEnv(std::map<std::string, std::string> newEnv)
 }
 
 
-Path absPath(Path path, Path dir)
+Path absPath(Path path, std::optional<Path> dir)
 {
     if (path[0] != '/') {
-        if (dir == "") {
+        if (!dir) {
 #ifdef __GNU__
             /* GNU (aka. GNU/Hurd) doesn't have any limitation on path
                lengths and doesn't define `PATH_MAX'.  */
@@ -116,7 +116,7 @@ Path absPath(Path path, Path dir)
             free(buf);
 #endif
         }
-        path = dir + "/" + path;
+        path = *dir + "/" + path;
     }
     return canonPath(path);
 }
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 559ed4332..8c2cef9e1 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -46,7 +46,7 @@ void clearEnv();
 /* Return an absolutized path, resolving paths relative to the
    specified directory, or the current directory otherwise.  The path
    is also canonicalised. */
-Path absPath(Path path, Path dir = "");
+Path absPath(Path path, std::optional<Path> dir = {});
 
 /* Canonicalise a path by removing all `.' or `..' components and
    double or trailing slashes.  Optionally resolves all symlink