From 8cb83b71b42ccf5fe279fa8a24a6a8f65507dc9c Mon Sep 17 00:00:00 2001
From: LE Manh Cuong <cuong.manhle.vn@gmail.com>
Date: Tue, 10 Jul 2018 02:50:39 +0700
Subject: [PATCH] imports: fix lost line between package and import statement

Fixes golang/go#26290

Change-Id: Ide797a46bf1d0d6070940fb5b9db3e76502bc528
Reviewed-on: https://go-review.googlesource.com/122736
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
---
 go/ast/astutil/imports.go      |  7 ++++---
 go/ast/astutil/imports_test.go |  2 ++
 imports/fix_test.go            | 36 ++++++++++++++++++++++++++++++++--
 3 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/go/ast/astutil/imports.go b/go/ast/astutil/imports.go
index 83f196cd5e..04ad6795d9 100644
--- a/go/ast/astutil/imports.go
+++ b/go/ast/astutil/imports.go
@@ -101,8 +101,8 @@ func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added
 			impDecl.TokPos = f.Decls[lastImport].End()
 		} else {
 			// There are no existing imports.
-			// Our new import goes after the package declaration and after
-			// the comment, if any, that starts on the same line as the
+			// Our new import, preceded by a blank line,  goes after the package declaration
+			// and after the comment, if any, that starts on the same line as the
 			// package declaration.
 			impDecl.TokPos = f.Package
 
@@ -112,7 +112,8 @@ func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added
 				if file.Line(c.Pos()) > pkgLine {
 					break
 				}
-				impDecl.TokPos = c.End()
+				// +2 for a blank line
+				impDecl.TokPos = c.End() + 2
 			}
 		}
 		f.Decls = append(f.Decls, nil)
diff --git a/go/ast/astutil/imports_test.go b/go/ast/astutil/imports_test.go
index 8bc3480873..da775ef4c2 100644
--- a/go/ast/astutil/imports_test.go
+++ b/go/ast/astutil/imports_test.go
@@ -367,6 +367,7 @@ type T time.Time
 type T time.Time
 `,
 		out: `package main // comment
+
 import "time"
 
 type T time.Time
@@ -399,6 +400,7 @@ type T time.Time
 `,
 		out: `// comment before
 package main // comment on
+
 import "time"
 
 type T time.Time
diff --git a/imports/fix_test.go b/imports/fix_test.go
index f9bac4610b..0d413e4304 100644
--- a/imports/fix_test.go
+++ b/imports/fix_test.go
@@ -1019,6 +1019,38 @@ func main() {
 		_ errors.Frame
 	)
 }
+`,
+	},
+
+	{
+		name: "issue #26290 1",
+		in: `package p // comment
+
+import "math"
+
+var _ = fmt.Printf
+`,
+		out: `package p // comment
+
+import "fmt"
+
+var _ = fmt.Printf
+`,
+	},
+
+	{
+		name: "issue #26290 2",
+		in: `package p
+
+import "math"
+
+var _ = fmt.Printf
+`,
+		out: `package p
+
+import "fmt"
+
+var _ = fmt.Printf
 `,
 	},
 }
@@ -1800,8 +1832,8 @@ func TestImportPathToNameGoPathParse(t *testing.T) {
 func TestIgnoreConfiguration(t *testing.T) {
 	testConfig{
 		gopathFiles: map[string]string{
-			".goimportsignore":       "# comment line\n\n example.net", // tests comment, blank line, whitespace trimming
-			"example.net/pkg/pkg.go": "package pkg\nconst X = 1",
+			".goimportsignore":                                     "# comment line\n\n example.net", // tests comment, blank line, whitespace trimming
+			"example.net/pkg/pkg.go":                               "package pkg\nconst X = 1",
 			"otherwise-longer-so-worse.example.net/foo/pkg/pkg.go": "package pkg\nconst X = 1",
 		},
 	}.test(t, func(t *goimportTest) {