From b85b6c64690dc75fd3096e452dbf8881456d0da7 Mon Sep 17 00:00:00 2001
From: Steffen Busch <37350514+steffenbusch@users.noreply.github.com>
Date: Wed, 7 Aug 2024 21:39:15 +0200
Subject: [PATCH] replacer: `{file.*}` global placeholder strips trailing
 newline (#6411)

Co-authored-by: Kanashimia <chad@redpilled.dev>
---
 .../foo_with_multiple_trailing_newlines.txt       |  2 ++
 .../testdata/foo_with_trailing_newline.txt        |  1 +
 replacer.go                                       |  3 +++
 replacer_test.go                                  | 15 +++++++++++++++
 4 files changed, 21 insertions(+)
 create mode 100644 caddytest/integration/testdata/foo_with_multiple_trailing_newlines.txt
 create mode 100644 caddytest/integration/testdata/foo_with_trailing_newline.txt

diff --git a/caddytest/integration/testdata/foo_with_multiple_trailing_newlines.txt b/caddytest/integration/testdata/foo_with_multiple_trailing_newlines.txt
new file mode 100644
index 00000000..75d7bfb8
--- /dev/null
+++ b/caddytest/integration/testdata/foo_with_multiple_trailing_newlines.txt
@@ -0,0 +1,2 @@
+foo
+
diff --git a/caddytest/integration/testdata/foo_with_trailing_newline.txt b/caddytest/integration/testdata/foo_with_trailing_newline.txt
new file mode 100644
index 00000000..257cc564
--- /dev/null
+++ b/caddytest/integration/testdata/foo_with_trailing_newline.txt
@@ -0,0 +1 @@
+foo
diff --git a/replacer.go b/replacer.go
index e5d2913e..65815c92 100644
--- a/replacer.go
+++ b/replacer.go
@@ -15,6 +15,7 @@
 package caddy
 
 import (
+	"bytes"
 	"fmt"
 	"io"
 	"net/http"
@@ -354,6 +355,8 @@ func (f fileReplacementProvider) replace(key string) (any, bool) {
 			zap.Error(err))
 		return nil, true
 	}
+	body = bytes.TrimSuffix(body, []byte("\n"))
+	body = bytes.TrimSuffix(body, []byte("\r"))
 	return string(body), true
 }
 
diff --git a/replacer_test.go b/replacer_test.go
index cf4d321b..1c1a7048 100644
--- a/replacer_test.go
+++ b/replacer_test.go
@@ -431,6 +431,14 @@ func TestReplacerNew(t *testing.T) {
 			variable: "file.caddytest/integration/testdata/foo.txt",
 			value:    "foo",
 		},
+		{
+			variable: "file.caddytest/integration/testdata/foo_with_trailing_newline.txt",
+			value:    "foo",
+		},
+		{
+			variable: "file.caddytest/integration/testdata/foo_with_multiple_trailing_newlines.txt",
+			value:    "foo" + getEOL(),
+		},
 	} {
 		if val, ok := repl.providers[1].replace(tc.variable); ok {
 			if val != tc.value {
@@ -442,6 +450,13 @@ func TestReplacerNew(t *testing.T) {
 	}
 }
 
+func getEOL() string {
+	if os.PathSeparator == '\\' {
+		return "\r\n" // Windows EOL
+	}
+	return "\n" // Unix and modern macOS EOL
+}
+
 func TestReplacerNewWithoutFile(t *testing.T) {
 	repl := NewReplacer().WithoutFile()