From 9a2482557dcc22736bdd6c0472903ca0a6e7e4e5 Mon Sep 17 00:00:00 2001
From: ridiculousfish <rf@fishshell.com>
Date: Fri, 17 Sep 2021 11:17:15 -0700
Subject: [PATCH] get_hostname_identifier to not return empty hostnames

When getting the hostname to construct the legacy uvar path, if the
hostname is empty, we will create a path pointing at a directory. On
BSDs this path can be successfully open'd and we will produce errors
about invalid uvar files.
---
 src/env_universal_common.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/env_universal_common.cpp b/src/env_universal_common.cpp
index 29f200a87..800f2ea2e 100644
--- a/src/env_universal_common.cpp
+++ b/src/env_universal_common.cpp
@@ -981,7 +981,8 @@ bool get_hostname_identifier(wcstring &result) {
     if (gethostname(hostname, sizeof(hostname)) == 0) {
         result.assign(str2wcstring(hostname));
         result.assign(truncate(result, HOSTNAME_LEN));
-        success = true;
+        // Don't return an empty hostname, we may attempt to open a directory instead.
+        success = !result.empty();
     }
     return success;
 }