Add strict option

ffjson.go

@@ -31,9 +31,10 @@ import (
 
 var outputPathFlag = flag.String("w", "", "Write generate code to this path instead of ${input}_ffjson.go.")
 var goCmdFlag = flag.String("go-cmd", "", "Path to go command; Useful for `goapp` support.")
+var strictDecodeFlag = flag.Bool("strict", false, "Returns an error when trying to decode unknow fields.")
 var importNameFlag = flag.String("import-name", "", "Override import name in case it cannot be detected.")
 var forceRegenerateFlag = flag.Bool("force-regenerate", false, "Regenerate every input file, without checking modification date.")
-var resetFields = flag.Bool("reset-fields", false, "When unmarshalling reset all fields missing in the JSON")
+var resetFields = flag.Bool("reset-fields", false, "When unmarshalling reset all fields missing in the JSON.")
 
 func usage() {
 	fmt.Fprintf(os.Stderr, "Usage of %s:\n\n", os.Args[0])
@@ -74,7 +75,7 @@ func main() {
 		importName = *importNameFlag
 	}
 
-	err := generator.GenerateFiles(goCmd, inputPath, outputPath, importName, *forceRegenerateFlag, *resetFields)
+	err := generator.GenerateFiles(goCmd, inputPath, outputPath, importName, *forceRegenerateFlag, *resetFields, *strictDecodeFlag)
 
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Error: %s:\n\n", err)

fflib/v1/errors.go

@@ -0,0 +1,18 @@
+package v1
+
+import "fmt"
+
+// ErrUnknowFields error is return when some unknow fields are found
+type ErrUnknowFields struct {
+	Fields []string
+}
+
+// NewErrUnknowFields create an instance UnknowFields error
+func NewErrUnknowFields(fields []string) *ErrUnknowFields {
+	return &ErrUnknowFields{
+		Fields: fields,
+	}
+}
+func (e *ErrUnknowFields) Error() string {
+	return fmt.Sprintf("unknow fields %v", e.Fields)
+}

generator/generator.go

@@ -18,13 +18,11 @@
 package generator
 
 import (
-	"errors"
 	"fmt"
 	"os"
 )
 
-func GenerateFiles(goCmd string, inputPath string, outputPath string, importName string, forceRegenerate bool, resetFields bool) error {
-
+func GenerateFiles(goCmd string, inputPath string, outputPath string, importName string, forceRegenerate bool, resetFields bool, strict bool) error {
 	if _, StatErr := os.Stat(outputPath); !os.IsNotExist(StatErr) {
 		inputFileInfo, inputFileErr := os.Stat(inputPath)
 		outputFileInfo, outputFileErr := os.Stat(outputPath)
@@ -43,11 +41,11 @@ func GenerateFiles(goCmd string, inputPath string, outputPath string, importName
 		return err
 	}
 
-	im := NewInceptionMain(goCmd, inputPath, outputPath, resetFields)
+	im := NewInceptionMain(goCmd, inputPath, outputPath, resetFields, strict)
 
 	err = im.Generate(packageName, structs, importName)
 	if err != nil {
-		return errors.New(fmt.Sprintf("error=%v path=%q", err, im.TempMainPath))
+		return fmt.Errorf("error=%v path=%q", err, im.TempMainPath)
 	}
 
 	err = im.Run()

inception/decoder.go

@@ -53,6 +53,7 @@ func CreateUnmarshalJSON(ic *Inception, si *StructInfo) error {
 		IC:          ic,
 		ValidValues: validValues,
 		ResetFields: ic.ResetFields,
+		Strict:      ic.Strict,
 	})
 
 	ic.OutputFuncs = append(ic.OutputFuncs, out)

inception/decoder_tpl.go

@@ -523,6 +523,7 @@ type ujFunc struct {
 	SI          *StructInfo
 	ValidValues []string
 	ResetFields bool
+	Strict      bool
 }
 
 var ujFuncTxt = `
@@ -537,6 +538,9 @@ func (uj *{{.SI.Name}}) UnmarshalJSON(input []byte) error {
 func (uj *{{.SI.Name}}) UnmarshalJSONFFLexer(fs *fflib.FFLexer, state fflib.FFParseState) error {
 	var err error = nil
 	currentKey := ffj_t_{{.SI.Name}}base
+	{{if eq .Strict true}}
+	var unknowKeys = make([]string, 0)
+	{{end}}
 	_ = currentKey
 	tok := fflib.FFTok_init
 	wantedTok := fflib.FFTok_init
@@ -610,6 +614,9 @@ mainparse:
 					goto mainparse
 				}
 				{{end}}
+				{{if eq .Strict true}}
+				unknowKeys = append(unknowKeys, string(kn))
+				{{end}}
 				currentKey = ffj_t_{{.SI.Name}}no_such_key
 				state = fflib.FFParse_want_colon
 				goto mainparse
@@ -696,6 +703,13 @@ done:
 	}
 {{end}}
 {{end}}
+
+{{if eq .Strict true}}
+	if len(unknowKeys) > 0 {
+		return fs.WrapErr(fflib.NewErrUnknowFields(unknowKeys))
+	}
+{{end}}
+
 	return nil
 }
 `

inception/inception.go

@@ -20,11 +20,12 @@ package ffjsoninception
 import (
 	"errors"
 	"fmt"
-	"github.com/pquerna/ffjson/shared"
 	"io/ioutil"
 	"os"
 	"reflect"
 	"sort"
+
+	"github.com/pquerna/ffjson/shared"
 )
 
 type Inception struct {
@@ -37,9 +38,10 @@ type Inception struct {
 	OutputFuncs   []string
 	q             ConditionalWrite
 	ResetFields   bool
+	Strict        bool
 }
 
-func NewInception(inputPath string, packageName string, outputPath string, resetFields bool) *Inception {
+func NewInception(inputPath string, packageName string, outputPath string, resetFields bool, strict bool) *Inception {
 	return &Inception{
 		objs:          make([]*StructInfo, 0),
 		InputPath:     inputPath,
@@ -48,6 +50,7 @@ func NewInception(inputPath string, packageName string, outputPath string, reset
 		OutputFuncs:   make([]string, 0),
 		OutputImports: make(map[string]bool),
 		ResetFields:   resetFields,
+		Strict:        strict,
 	}
 }