From 9368d6ccbfe57bc54b433b22b2008d3c4faf086d Mon Sep 17 00:00:00 2001
From: Dmitri Shuralyov <shurcooL@gmail.com>
Date: Fri, 22 Aug 2014 10:18:00 -0700
Subject: [PATCH] cmd/gofmt: fix error on partial Go code ending with line
 comment.

Fix issue by always appending newline after user input, before
the closing curly bracket. The adjust func is modified to remove
this new newline.

Add test case (it fails before CL, passes after).

Fixes #8411.

LGTM=gri
R=golang-codereviews, bradfitz, josharian, gri
CC=golang-codereviews
https://golang.org/cl/124700043
---
 src/cmd/gofmt/gofmt.go               | 4 ++--
 src/cmd/gofmt/testdata/stdin5.golden | 3 +++
 src/cmd/gofmt/testdata/stdin5.input  | 3 +++
 3 files changed, 8 insertions(+), 2 deletions(-)
 create mode 100644 src/cmd/gofmt/testdata/stdin5.golden
 create mode 100644 src/cmd/gofmt/testdata/stdin5.input

diff --git a/src/cmd/gofmt/gofmt.go b/src/cmd/gofmt/gofmt.go
index 576cae5228e..f7d30d84052 100644
--- a/src/cmd/gofmt/gofmt.go
+++ b/src/cmd/gofmt/gofmt.go
@@ -277,14 +277,14 @@ func parse(fset *token.FileSet, filename string, src []byte, stdin bool) (*ast.F
 	// into a function body.  This handles expressions too.
 	// Insert using a ;, not a newline, so that the line numbers
 	// in fsrc match the ones in src.
-	fsrc := append(append([]byte("package p; func _() {"), src...), '}')
+	fsrc := append(append([]byte("package p; func _() {"), src...), '\n', '}')
 	file, err = parser.ParseFile(fset, filename, fsrc, parserMode)
 	if err == nil {
 		adjust := func(orig, src []byte) []byte {
 			// Remove the wrapping.
 			// Gofmt has turned the ; into a \n\n.
 			src = src[len("package p\n\nfunc _() {"):]
-			src = src[:len(src)-len("}\n")]
+			src = src[:len(src)-len("\n}\n")]
 			// Gofmt has also indented the function body one level.
 			// Remove that indent.
 			src = bytes.Replace(src, []byte("\n\t"), []byte("\n"), -1)
diff --git a/src/cmd/gofmt/testdata/stdin5.golden b/src/cmd/gofmt/testdata/stdin5.golden
new file mode 100644
index 00000000000..31ce6b24852
--- /dev/null
+++ b/src/cmd/gofmt/testdata/stdin5.golden
@@ -0,0 +1,3 @@
+//gofmt -stdin
+
+i := 5 // Line comment without newline.
\ No newline at end of file
diff --git a/src/cmd/gofmt/testdata/stdin5.input b/src/cmd/gofmt/testdata/stdin5.input
new file mode 100644
index 00000000000..0a7c97d180c
--- /dev/null
+++ b/src/cmd/gofmt/testdata/stdin5.input
@@ -0,0 +1,3 @@
+//gofmt -stdin
+
+i  :=5// Line comment without newline.
\ No newline at end of file