From 6ef904977f492db1a8fde6cee801ea0eb2da7284 Mon Sep 17 00:00:00 2001
From: devteamaegis <devteamaegis@users.noreply.github.com>
Date: Thu, 11 Jun 2026 03:32:54 -0400
Subject: [PATCH] fix(crontab): avoid panic on env line with empty value

A crontab env line with an empty value (e.g. "FOO=") matched the env
regex with an empty value group, and the quote-stripping check indexed
envVal[0] unconditionally, panicking with index out of range on the
empty string. Guard the quote check on len(envVal) > 0 so an empty
assignment parses to an empty value, matching Vixie cron behavior.
---
 crontab/crontab.go      |  2 +-
 crontab/crontab_test.go | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/crontab/crontab.go b/crontab/crontab.go
index e55937d..a07eeee 100644
--- a/crontab/crontab.go
+++ b/crontab/crontab.go
@@ -85,7 +85,7 @@ func ParseCrontab(reader io.Reader) (*Crontab, error) {
 			envVal := r[0][2]
 
 			// Remove quotes (this emulates what Vixie cron does)
-			if envVal[0] == '"' || envVal[0] == '\'' {
+			if len(envVal) > 0 && (envVal[0] == '"' || envVal[0] == '\'') {
 				if len(envVal) > 1 && envVal[0] == envVal[len(envVal)-1] {
 					envVal = envVal[1 : len(envVal)-1]
 				}
diff --git a/crontab/crontab_test.go b/crontab/crontab_test.go
index 995d7c7..df8a7b0 100644
--- a/crontab/crontab_test.go
+++ b/crontab/crontab_test.go
@@ -110,6 +110,18 @@ var parseCrontabTestCases = []struct {
 		},
 	},
 
+	{
+		"FOO=",
+		&Crontab{
+			Context: &Context{
+				Shell:    "/bin/sh",
+				Environ:  map[string]string{"FOO": ""},
+				Timezone: time.Local,
+			},
+			Jobs: []*Job{},
+		},
+	},
+
 	{
 		"CRON_TZ=UTC",
 		&Crontab{