From d1848506f8b07797a8bfbb6a0c2b36b1a34f6458 Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Sun, 24 Mar 2024 00:45:57 +0100
Subject: [PATCH] local-derivation-goal.cc: Remove *all* trailing slashes

(cherry picked from commit dd26f413791b7885558afcc628623648b7fa6396)
---
 src/libstore/build/local-derivation-goal.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/libstore/build/local-derivation-goal.cc b/src/libstore/build/local-derivation-goal.cc
index 6e583c333..cc401f57f 100644
--- a/src/libstore/build/local-derivation-goal.cc
+++ b/src/libstore/build/local-derivation-goal.cc
@@ -2119,7 +2119,8 @@ void LocalDerivationGoal::runChild()
             Path globalTmpDir = canonPath(defaultTempDir(), true);
 
             /* They don't like trailing slashes on subpath directives */
-            if (globalTmpDir.back() == '/') globalTmpDir.pop_back();
+            while (!globalTmpDir.empty() && globalTmpDir.back() == '/')
+                globalTmpDir.pop_back();
 
             if (getEnv("_NIX_TEST_NO_SANDBOX") != "1") {
                 builder = "/usr/bin/sandbox-exec";