gofix: trivial rewrite for template.ParseFiles

Also warn about uses of Set.

R=rsc
CC=golang-dev
https://golang.org/cl/5436051

src/cmd/gofix/Makefile

@@ -31,6 +31,7 @@ GOFILES=\
 	sorthelpers.go\
 	sortslice.go\
 	stringssplit.go\
+	template.go\
 	typecheck.go\
 	url.go\
 

src/cmd/gofix/template.go

+// Copyright 2011 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(templateFix)
+}
+
+var templateFix = fix{
+	"template",
+	"2011-11-22",
+	template,
+	`Rewrite calls to template.ParseFile to template.ParseFiles
+
+http://codereview.appspot.com/5433048
+`,
+}
+
+var templateSetGlobals = []string{
+	"ParseSetFiles",
+	"ParseSetGlob",
+	"ParseTemplateFiles",
+	"ParseTemplateGlob",
+	"Set",
+	"SetMust",
+}
+
+var templateSetMethods = []string{
+	"ParseSetFiles",
+	"ParseSetGlob",
+	"ParseTemplateFiles",
+	"ParseTemplateGlob",
+}
+
+var templateTypeConfig = &TypeConfig{
+	Type: map[string]*Type{
+		"template.Template": &Type{
+			Method: map[string]string{
+				"Funcs":      "func() *template.Template",
+				"Delims":     "func() *template.Template",
+				"Parse":      "func() (*template.Template, error)",
+				"ParseFile":  "func() (*template.Template, error)",
+				"ParseInSet": "func() (*template.Template, error)",
+			},
+		},
+		"template.Set": &Type{
+			Method: map[string]string{
+				"ParseSetFiles":      "func() (*template.Set, error)",
+				"ParseSetGlob":       "func() (*template.Set, error)",
+				"ParseTemplateFiles": "func() (*template.Set, error)",
+				"ParseTemplateGlob":  "func() (*template.Set, error)",
+			},
+		},
+	},
+
+	Func: map[string]string{
+		"template.New":     "*template.Template",
+		"template.Must":    "(*template.Template, error)",
+		"template.SetMust": "(*template.Set, error)",
+	},
+}
+
+func template(f *ast.File) bool {
+	if !imports(f, "text/template") && !imports(f, "html/template") {
+		return false
+	}
+
+	fixed := false
+
+	typeof, _ := typecheck(templateTypeConfig, f)
+
+	// Now update the names used by importers.
+	walk(f, func(n interface{}) {
+		if sel, ok := n.(*ast.SelectorExpr); ok {
+			// Reference to top-level function ParseFile.
+			if isPkgDot(sel, "template", "ParseFile") {
+				sel.Sel.Name = "ParseFiles"
+				fixed = true
+				return
+			}
+			// Reference to ParseFiles method.
+			if typeof[sel.X] == "*template.Template" && sel.Sel.Name == "ParseFile" {
+				sel.Sel.Name = "ParseFiles"
+				fixed = true
+				return
+			}
+			// The Set type and its functions are now gone.
+			for _, name := range templateSetGlobals {
+				if isPkgDot(sel, "template", name) {
+					warn(sel.Pos(), "reference to template.%s must be fixed manually", name)
+					return
+				}
+			}
+			// The methods of Set are now gone.
+			for _, name := range templateSetMethods {
+				if typeof[sel.X] == "*template.Set" && sel.Sel.Name == name {
+					warn(sel.Pos(), "reference to template.*Set.%s must be fixed manually", name)
+					return
+				}
+			}
+		}
+	})
+
+	return fixed
+}

src/cmd/gofix/template_test.go

+// Copyright 2011 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(templateTests, template)
+}
+
+var templateTests = []testCase{
+	{
+		Name: "template.0",
+		In: `package main
+
+import (
+	"text/template"
+)
+
+func f() {
+	template.ParseFile(a)
+	var t template.Template
+	x, y := template.ParseFile()
+	template.New("x").Funcs(m).ParseFile(a) // chained method
+	// Output should complain about these as functions or methods.
+	var s *template.Set
+	s.ParseSetFiles(a)
+	template.ParseSetGlob(a)
+	s.ParseTemplateFiles(a)
+	template.ParseTemplateGlob(a)
+	x := template.SetMust(a())
+}
+`,
+		Out: `package main
+
+import (
+	"text/template"
+)
+
+func f() {
+	template.ParseFiles(a)
+	var t template.Template
+	x, y := template.ParseFiles()
+	template.New("x").Funcs(m).ParseFiles(a) // chained method
+	// Output should complain about these as functions or methods.
+	var s *template.Set
+	s.ParseSetFiles(a)
+	template.ParseSetGlob(a)
+	s.ParseTemplateFiles(a)
+	template.ParseTemplateGlob(a)
+	x := template.SetMust(a())
+}
+`,
+	},
+}