From c262ffbb68e6dfc30b619e6ce6bdbd00f27b8a71 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc=20Cornell=C3=A0?= <marc@mcornella.com>
Date: Thu, 18 Apr 2024 07:16:42 +0200
Subject: [PATCH] fix(update): define `$ZSH` if undefined (#12273)

Fixes #12273
Fixes https://github.com/topgrade-rs/topgrade/issues/519
---
 tools/upgrade.sh | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/tools/upgrade.sh b/tools/upgrade.sh
index d7016aa44..5eb90ab41 100755
--- a/tools/upgrade.sh
+++ b/tools/upgrade.sh
@@ -10,9 +10,14 @@ fi
 
 # Protect against unwanted sourcing
 case "$ZSH_EVAL_CONTEXT" in
-  *:file) echo "error: this file should not be sourced" && return ;;
+  *:file) echo "error: this file should not be sourced" && return 1 ;;
 esac
 
+# Define "$ZSH" if not defined -- in theory this should be `export`ed by the calling script
+if [[ -z "$ZSH" ]]; then
+  ZSH="${0:a:h:h}"
+fi
+
 cd "$ZSH"
 
 verbose_mode="default"