From 4ee0d8a960a7c00b6147d566176cb54e4530ffa9 Mon Sep 17 00:00:00 2001
From: Hank Donnay <hdonnay@redhat.com>
Date: Thu, 8 Feb 2024 09:23:20 -0600
Subject: [PATCH] dockerfile: fix `escape` parser directive

Signed-off-by: Hank Donnay <hdonnay@redhat.com>
---
 rhel/dockerfile/dockerfile.go         | 4 ++--
 rhel/dockerfile/testdata/Escape.txtar | 8 ++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)
 create mode 100644 rhel/dockerfile/testdata/Escape.txtar

diff --git a/rhel/dockerfile/dockerfile.go b/rhel/dockerfile/dockerfile.go
index e49a3688a..3e24df4e0 100644
--- a/rhel/dockerfile/dockerfile.go
+++ b/rhel/dockerfile/dockerfile.go
@@ -100,9 +100,9 @@ func (p *labelParser) Run() error {
 			if strings.Contains(v, `escape=`) {
 				eq := strings.IndexByte(v, '=')
 				if eq == -1 {
-					return fmt.Errorf("botched parser directive: %#q", i.val)
+					panic("string changed while parsing?")
 				}
-				esc, _ := utf8.DecodeRuneInString(v[:eq+1])
+				esc, _ := utf8.DecodeRuneInString(v[eq+1:])
 				p.lex.Escape(esc)
 				p.unquote.Escape(esc)
 				p.vars.Escape(esc)
diff --git a/rhel/dockerfile/testdata/Escape.txtar b/rhel/dockerfile/testdata/Escape.txtar
new file mode 100644
index 000000000..3e9bb865b
--- /dev/null
+++ b/rhel/dockerfile/testdata/Escape.txtar
@@ -0,0 +1,8 @@
+-- Dockerfile --
+# escape=ꙮ
+LABEL a ꙮ
+ꙮ$b
+-- Want --
+{
+  "a": "$b"
+}