Add gen-stringify-test.go

github/gen-accessors.go

@@ -7,8 +7,9 @@
 
 // gen-accessors generates accessor methods for structs with pointer fields.
 //
-// It is meant to be used by the go-github authors in conjunction with the
-// go generate tool before sending a commit to GitHub.
+// It is meant to be used by go-github contributors in conjunction with the
+// go generate tool before sending a PR to GitHub.
+// Please see the CONTRIBUTING.md file for more information.
 package main
 
 import (

github/gen-stringify-test.go

@@ -0,0 +1,358 @@
+// Copyright 2019 The go-github AUTHORS. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore
+
+// gen-stringify-test generates test methods to test the String methods.
+//
+// These tests eliminate most of the code coverage problems so that real
+// code coverage issues can be more readily identified.
+//
+// It is meant to be used by go-github contributors in conjunction with the
+// go generate tool before sending a PR to GitHub.
+// Please see the CONTRIBUTING.md file for more information.
+package main
+
+import (
+	"bytes"
+	"flag"
+	"fmt"
+	"go/ast"
+	"go/format"
+	"go/parser"
+	"go/token"
+	"io/ioutil"
+	"log"
+	"os"
+	"strings"
+	"text/template"
+)
+
+const (
+	ignoreFilePrefix1 = "gen-"
+	ignoreFilePrefix2 = "github-"
+	outputFileSuffix  = "-stringify_test.go"
+)
+
+var (
+	verbose = flag.Bool("v", false, "Print verbose log messages")
+
+	sourceTmpl = template.Must(template.New("source").Funcs(funcMap).Parse(source))
+
+	// blacklistStructMethod lists "struct.method" combos to skip.
+	blacklistStructMethod = map[string]bool{}
+	// blacklistStruct lists structs to skip.
+	blacklistStruct = map[string]bool{
+		"RateLimits": true,
+	}
+
+	funcMap = template.FuncMap{
+		"isNotLast": func(index int, slice []*structField) string {
+			if index+1 < len(slice) {
+				return ", "
+			}
+			return ""
+		},
+		"processZeroValue": func(v string) string {
+			switch v {
+			case "Bool(false)":
+				return "false"
+			case "Float64(0.0)":
+				return "0"
+			case "0", "Int(0)", "Int64(0)":
+				return "0"
+			case `""`, `String("")`:
+				return `""`
+			case "Timestamp{}", "&Timestamp{}":
+				return "github.Timestamp{0001-01-01 00:00:00 +0000 UTC}"
+			case "nil":
+				return "map[]"
+			}
+			log.Fatalf("Unhandled zero value: %q", v)
+			return ""
+		},
+	}
+)
+
+func main() {
+	flag.Parse()
+	fset := token.NewFileSet()
+
+	pkgs, err := parser.ParseDir(fset, ".", sourceFilter, 0)
+	if err != nil {
+		log.Fatal(err)
+		return
+	}
+
+	for pkgName, pkg := range pkgs {
+		t := &templateData{
+			filename:     pkgName + outputFileSuffix,
+			Year:         2019,
+			Package:      pkgName,
+			Imports:      map[string]string{"testing": "testing"},
+			StringFuncs:  map[string]bool{},
+			StructFields: map[string][]*structField{},
+		}
+		for filename, f := range pkg.Files {
+			logf("Processing %v...", filename)
+			if err := t.processAST(f); err != nil {
+				log.Fatal(err)
+			}
+		}
+		if err := t.dump(); err != nil {
+			log.Fatal(err)
+		}
+	}
+	logf("Done.")
+}
+
+func sourceFilter(fi os.FileInfo) bool {
+	return !strings.HasSuffix(fi.Name(), "_test.go") &&
+		!strings.HasPrefix(fi.Name(), ignoreFilePrefix1) &&
+		!strings.HasPrefix(fi.Name(), ignoreFilePrefix2)
+}
+
+type templateData struct {
+	filename     string
+	Year         int
+	Package      string
+	Imports      map[string]string
+	StringFuncs  map[string]bool
+	StructFields map[string][]*structField
+}
+
+type structField struct {
+	sortVal      string // Lower-case version of "ReceiverType.FieldName".
+	ReceiverVar  string // The one-letter variable name to match the ReceiverType.
+	ReceiverType string
+	FieldName    string
+	FieldType    string
+	ZeroValue    string
+	NamedStruct  bool // Getter for named struct.
+}
+
+func (t *templateData) processAST(f *ast.File) error {
+	for _, decl := range f.Decls {
+		fn, ok := decl.(*ast.FuncDecl)
+		if ok {
+			if fn.Recv != nil && len(fn.Recv.List) > 0 {
+				id, ok := fn.Recv.List[0].Type.(*ast.Ident)
+				if ok && fn.Name.Name == "String" {
+					logf("Got FuncDecl: Name=%q, id.Name=%#v", fn.Name.Name, id.Name)
+					t.StringFuncs[id.Name] = true
+				} else {
+					logf("Ignoring FuncDecl: Name=%q, Type=%T", fn.Name.Name, fn.Recv.List[0].Type)
+				}
+			} else {
+				logf("Ignoring FuncDecl: Name=%q, fn=%#v", fn.Name.Name, fn)
+			}
+			continue
+		}
+
+		gd, ok := decl.(*ast.GenDecl)
+		if !ok {
+			logf("Ignoring AST decl type %T", decl)
+			continue
+		}
+		for _, spec := range gd.Specs {
+			ts, ok := spec.(*ast.TypeSpec)
+			if !ok {
+				continue
+			}
+			// Skip unexported identifiers.
+			if !ts.Name.IsExported() {
+				logf("Struct %v is unexported; skipping.", ts.Name)
+				continue
+			}
+			// Check if the struct is blacklisted.
+			if blacklistStruct[ts.Name.Name] {
+				logf("Struct %v is blacklisted; skipping.", ts.Name)
+				continue
+			}
+			st, ok := ts.Type.(*ast.StructType)
+			if !ok {
+				logf("Ignoring AST type %T, Name=%q", ts.Type, ts.Name.String())
+				continue
+			}
+			for _, field := range st.Fields.List {
+				if len(field.Names) == 0 {
+					continue
+				}
+
+				fieldName := field.Names[0]
+				if id, ok := field.Type.(*ast.Ident); ok {
+					t.addIdent(id, ts.Name.String(), fieldName.String())
+					continue
+				}
+
+				if _, ok := field.Type.(*ast.MapType); ok {
+					t.addMapType(ts.Name.String(), fieldName.String())
+					continue
+				}
+
+				se, ok := field.Type.(*ast.StarExpr)
+				if !ok {
+					logf("Ignoring type %T for Name=%q, FieldName=%q", field.Type, ts.Name.String(), fieldName.String())
+					continue
+				}
+
+				// Skip unexported identifiers.
+				if !fieldName.IsExported() {
+					logf("Field %v is unexported; skipping.", fieldName)
+					continue
+				}
+				// Check if "struct.method" is blacklisted.
+				if key := fmt.Sprintf("%v.Get%v", ts.Name, fieldName); blacklistStructMethod[key] {
+					logf("Method %v is blacklisted; skipping.", key)
+					continue
+				}
+
+				switch x := se.X.(type) {
+				case *ast.ArrayType:
+				case *ast.Ident:
+					t.addIdentPtr(x, ts.Name.String(), fieldName.String())
+				case *ast.MapType:
+				case *ast.SelectorExpr:
+				default:
+					logf("processAST: type %q, field %q, unknown %T: %+v", ts.Name, fieldName, x, x)
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func (t *templateData) addMapType(receiverType, fieldName string) {
+	t.StructFields[receiverType] = append(t.StructFields[receiverType], newStructField(receiverType, fieldName, "map[]", "nil", false))
+}
+
+func (t *templateData) addIdent(x *ast.Ident, receiverType, fieldName string) {
+	var zeroValue string
+	var namedStruct = false
+	switch x.String() {
+	case "int":
+		zeroValue = "0"
+	case "int64":
+		zeroValue = "0"
+	case "float64":
+		zeroValue = "0.0"
+	case "string":
+		zeroValue = `""`
+	case "bool":
+		zeroValue = "false"
+	case "Timestamp":
+		zeroValue = "Timestamp{}"
+	default:
+		zeroValue = "nil"
+		namedStruct = true
+	}
+
+	t.StructFields[receiverType] = append(t.StructFields[receiverType], newStructField(receiverType, fieldName, x.String(), zeroValue, namedStruct))
+}
+
+func (t *templateData) addIdentPtr(x *ast.Ident, receiverType, fieldName string) {
+	var zeroValue string
+	var namedStruct = false
+	switch x.String() {
+	case "int":
+		zeroValue = "Int(0)"
+	case "int64":
+		zeroValue = "Int64(0)"
+	case "float64":
+		zeroValue = "Float64(0.0)"
+	case "string":
+		zeroValue = `String("")`
+	case "bool":
+		zeroValue = "Bool(false)"
+	case "Timestamp":
+		zeroValue = "&Timestamp{}"
+	default:
+		zeroValue = "nil"
+		namedStruct = true
+	}
+
+	t.StructFields[receiverType] = append(t.StructFields[receiverType], newStructField(receiverType, fieldName, x.String(), zeroValue, namedStruct))
+}
+
+func (t *templateData) dump() error {
+	if len(t.StructFields) == 0 {
+		logf("No StructFields for %v; skipping.", t.filename)
+		return nil
+	}
+
+	// Remove unused structs.
+	var toDelete []string
+	for k := range t.StructFields {
+		if !t.StringFuncs[k] {
+			toDelete = append(toDelete, k)
+			continue
+		}
+	}
+	for _, k := range toDelete {
+		delete(t.StructFields, k)
+	}
+
+	var buf bytes.Buffer
+	if err := sourceTmpl.Execute(&buf, t); err != nil {
+		return err
+	}
+	clean, err := format.Source(buf.Bytes())
+	if err != nil {
+		log.Printf("failed-to-format source:\n%v", buf.String())
+		return err
+	}
+
+	logf("Writing %v...", t.filename)
+	return ioutil.WriteFile(t.filename, clean, 0644)
+}
+
+func newStructField(receiverType, fieldName, fieldType, zeroValue string, namedStruct bool) *structField {
+	return &structField{
+		sortVal:      strings.ToLower(receiverType) + "." + strings.ToLower(fieldName),
+		ReceiverVar:  strings.ToLower(receiverType[:1]),
+		ReceiverType: receiverType,
+		FieldName:    fieldName,
+		FieldType:    fieldType,
+		ZeroValue:    zeroValue,
+		NamedStruct:  namedStruct,
+	}
+}
+
+func logf(fmt string, args ...interface{}) {
+	if *verbose {
+		log.Printf(fmt, args...)
+	}
+}
+
+const source = `// Copyright {{.Year}} The go-github AUTHORS. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by gen-stringify-tests; DO NOT EDIT.
+
+package {{ $package := .Package}}{{$package}}
+{{with .Imports}}
+import (
+  {{- range . -}}
+  "{{.}}"
+  {{end -}}
+)
+{{end}}
+func Float64(v float64) *float64 { return &v }
+{{range $key, $value := .StructFields}}
+func Test{{ $key }}_String(t *testing.T) {
+  v := {{ $key }}{ {{range .}}{{if .NamedStruct}}
+    {{ .FieldName }}: &{{ .FieldType }}{},{{else}}
+    {{ .FieldName }}: {{.ZeroValue}},{{end}}{{end}}
+  }
+ 	want := ` + "`" + `{{ $package }}.{{ $key }}{{ $slice := . }}{
+{{- range $ind, $val := .}}{{if .NamedStruct}}{{ .FieldName }}:{{ $package }}.{{ .FieldType }}{}{{else}}{{ .FieldName }}:{{ processZeroValue .ZeroValue }}{{end}}{{ isNotLast $ind $slice }}{{end}}}` + "`" + `
+	if got := v.String(); got != want {
+		t.Errorf("{{ $key }}.String = %v, want %v", got, want)
+	}
+}
+{{end}}
+`