From f0864d3880dc032324bce5b150ec9ede26e3358b Mon Sep 17 00:00:00 2001
From: Nalin Dahyabhai <nalin@redhat.com>
Date: Thu, 3 Apr 2025 13:31:09 -0400
Subject: [PATCH] pkg/build/builder/util/dockerfile.Write: reproduce heredocs

When writing out the contents of a parsed Dockerfile, attempt to
reproduce heredocs that followed instructions.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>
---
 .../builder/util/dockerfile/dockerfile.go     |  5 ++++
 .../util/dockerfile/dockerfile_test.go        | 30 +++++++++++++++++++
 2 files changed, 35 insertions(+)

diff --git a/pkg/build/builder/util/dockerfile/dockerfile.go b/pkg/build/builder/util/dockerfile/dockerfile.go
index 6b0292cbfc..f671795282 100644
--- a/pkg/build/builder/util/dockerfile/dockerfile.go
+++ b/pkg/build/builder/util/dockerfile/dockerfile.go
@@ -62,6 +62,11 @@ func Write(node *parser.Node) []byte {
 				}
 				buf.Write([]byte(n.Value))
 			}
+			for _, heredoc := range node.Heredocs {
+				buf.Write([]byte(heredoc.Content))
+				buf.Write([]byte("\n"))
+				buf.Write([]byte(heredoc.Name))
+			}
 			buf.Write([]byte("\n"))
 			return buf.Bytes()
 		}
diff --git a/pkg/build/builder/util/dockerfile/dockerfile_test.go b/pkg/build/builder/util/dockerfile/dockerfile_test.go
index a734e54721..2bf9240cf1 100644
--- a/pkg/build/builder/util/dockerfile/dockerfile_test.go
+++ b/pkg/build/builder/util/dockerfile/dockerfile_test.go
@@ -92,6 +92,36 @@ CMD ["-c","env"]
 USER 1001
 WORKDIR /home
 HEALTHCHECK --interval=60s --timeout=10s CMD ["/usr/bin/true"]
+`,
+		},
+		"Dockerfile with heredoc": {
+			in: `# This is a Dockerfile
+FROM scratch
+LABEL version=1.0
+# Here we start building a second image
+FROM busybox
+ENV PATH=/bin
+RUN <<EOF <<ALSO
+pwd
+EOF
+ls -1
+ALSO
+RUN <<EOF
+["ls","-1"]
+EOF
+`,
+			want: `FROM scratch
+LABEL version=1.0
+FROM busybox
+ENV PATH=/bin
+RUN <<EOF <<ALSO
+pwd
+EOF
+ls -1
+ALSO
+RUN <<EOF
+["ls","-1"]
+EOF
 `,
 		},
 	}