cmd/fix: add golang.org/x/net/context fix

Fixes #17040

Change-Id: I3682cc0367b919084c280d7dc64746495c1d4aaa
Reviewed-on: https://go-review.googlesource.com/28872
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/fix/context.go

@@ -0,0 +1,25 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"go/ast"
+)
+
+func init() {
+	register(contextFix)
+}
+
+var contextFix = fix{
+	name:     "context",
+	date:     "2016-09-09",
+	f:        ctxfix,
+	desc:     `Change imports of golang.org/x/net/context to context`,
+	disabled: true,
+}
+
+func ctxfix(f *ast.File) bool {
+	return rewriteImport(f, "golang.org/x/net/context", "context")
+}

src/cmd/fix/context_test.go

@@ -0,0 +1,42 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func init() {
+	addTestCases(contextTests, ctxfix)
+}
+
+var contextTests = []testCase{
+	{
+		Name: "context.0",
+		In: `package main
+
+import "golang.org/x/net/context"
+
+var _ = "golang.org/x/net/context"
+`,
+		Out: `package main
+
+import "context"
+
+var _ = "golang.org/x/net/context"
+`,
+	},
+	{
+		Name: "context.1",
+		In: `package main
+
+import ctx "golang.org/x/net/context"
+
+var _ = ctx.Background()
+`,
+		Out: `package main
+
+import ctx "context"
+
+var _ = ctx.Background()
+`,
+	},
+}

src/cmd/fix/fix.go

@@ -17,10 +17,11 @@ import (
 )
 
 type fix struct {
-	name string
-	date string // date that fix was introduced, in YYYY-MM-DD format
-	f    func(*ast.File) bool
-	desc string
+	name     string
+	date     string // date that fix was introduced, in YYYY-MM-DD format
+	f        func(*ast.File) bool
+	desc     string
+	disabled bool // whether this fix should be disabled by default
 }
 
 // main runs sort.Sort(byName(fixes)) before printing list of fixes.

src/cmd/fix/gotypes.go

@@ -14,10 +14,10 @@ func init() {
 }
 
 var gotypesFix = fix{
-	"gotypes",
-	"2015-07-16",
-	gotypes,
-	`Change imports of golang.org/x/tools/go/{exact,types} to go/{constant,types}`,
+	name: "gotypes",
+	date: "2015-07-16",
+	f:    gotypes,
+	desc: `Change imports of golang.org/x/tools/go/{exact,types} to go/{constant,types}`,
 }
 
 func gotypes(f *ast.File) bool {

src/cmd/fix/main.go

@@ -45,7 +45,11 @@ func usage() {
 	fmt.Fprintf(os.Stderr, "\nAvailable rewrites are:\n")
 	sort.Sort(byName(fixes))
 	for _, f := range fixes {
-		fmt.Fprintf(os.Stderr, "\n%s\n", f.name)
+		if f.disabled {
+			fmt.Fprintf(os.Stderr, "\n%s (disabled)\n", f.name)
+		} else {
+			fmt.Fprintf(os.Stderr, "\n%s\n", f.name)
+		}
 		desc := strings.TrimSpace(f.desc)
 		desc = strings.Replace(desc, "\n", "\n\t", -1)
 		fmt.Fprintf(os.Stderr, "\t%s\n", desc)
@@ -139,6 +143,9 @@ func processFile(filename string, useStdin bool) error {
 		if allowed != nil && !allowed[fix.name] {
 			continue
 		}
+		if fix.disabled && !force[fix.name] {
+			continue
+		}
 		if fix.f(newFile) {
 			fixed = true
 			fmt.Fprintf(&fixlog, " %s", fix.name)

src/cmd/fix/netipv6zone.go

@@ -11,10 +11,10 @@ func init() {
 }
 
 var netipv6zoneFix = fix{
-	"netipv6zone",
-	"2012-11-26",
-	netipv6zone,
-	`Adapt element key to IPAddr, UDPAddr or TCPAddr composite literals.
+	name: "netipv6zone",
+	date: "2012-11-26",
+	f:    netipv6zone,
+	desc: `Adapt element key to IPAddr, UDPAddr or TCPAddr composite literals.
 
 https://codereview.appspot.com/6849045/
 `,

src/cmd/fix/printerconfig.go

@@ -11,10 +11,10 @@ func init() {
 }
 
 var printerconfigFix = fix{
-	"printerconfig",
-	"2012-12-11",
-	printerconfig,
-	`Add element keys to Config composite literals.`,
+	name: "printerconfig",
+	date: "2012-12-11",
+	f:    printerconfig,
+	desc: `Add element keys to Config composite literals.`,
 }
 
 func printerconfig(f *ast.File) bool {