Allow the option to not return an error (#21)

Makefile

@@ -6,6 +6,7 @@ test:
 	$(MAKE) lint
 	go test ./...
 	diff test/config_options.go test/golden/config_options.go.txt
+	diff test/configWithNoError_options.go test/golden/configWithNoError_options.go.txt
 
 generate:
 	go generate .

main.go

@@ -31,6 +31,7 @@ var imports string
 var quoteStrings bool
 var implementEqual bool
 var implementString bool
+var returnError bool
 
 var Usage = func() {
 	fmt.Fprintf(flag.CommandLine.Output(), "Usage of %s <type>:\n\n", os.Args[0])
@@ -53,6 +54,7 @@ func initFlags() {
 	flag.BoolVar(&quoteStrings, "quote-default-strings", true, `set to false to disable automatic quoting of string field defaults`)
 	flag.BoolVar(&implementString, "stringer", true, `set to false to disable creating String() method for options`)
 	flag.BoolVar(&implementEqual, "cmp", true, `set to false to disable creating Equals() method for options`)
+	flag.BoolVar(&returnError, "noerror", true, `set to false if you do not want to return an error when creating a new config`)
 	flag.BoolVar(&runGoFmt, "fmt", true, `set to false to skip go format`)
 	flag.Usage = Usage
 }
@@ -285,6 +287,7 @@ func writeOptionsFile(types []string, packageName string, node ast.Node, fset *t
 			"createNewFunc":       createNewFunc,
 			"implementEqual":      implementEqual,
 			"implementString":     implementString,
+			"returnError":         returnError,
 		})
 		if err != nil {
 			log.Fatal(fmt.Errorf("template execute failed: %s", err))

render.gotmpl

@@ -18,45 +18,56 @@ import "github.com/google/go-cmp/cmp"
 
 {{ $applyOptionFuncType := or $.applyOptionFuncType (printf "Apply%sFunc" (ToPublic $.optionTypeName)) }}
 
-type {{ $applyOptionFuncType }} func(c *{{ $.configTypeName }}) error
+type {{ $applyOptionFuncType }} func(c *{{ $.configTypeName }}) {{ if $.returnError -}} error {{ end }}
 
-func (f {{ $applyOptionFuncType }}) apply(c *{{ $.configTypeName }}) error {
-    return f(c)
+func (f {{ $applyOptionFuncType }}) apply(c *{{ $.configTypeName }}) {{ if $.returnError -}} error {{ end }} {
+    {{ if $.returnError -}} return {{ end }} f(c)
 }
 
 {{ $applyFuncName := or $.applyFuncName (printf "apply%sOptions" (ToPublic $.configTypeName)) }}
 
 {{ if $.createNewFunc}}
-func new{{ $.configTypeName | ToPublic}}(options ...{{ $.optionTypeName }}) ({{ $.configTypeName }}, error) {
+func new{{ $.configTypeName | ToPublic}}(options ...{{ $.optionTypeName }}) {{ if $.returnError -}} ({{ $.configTypeName }} , error) {{else}} {{ $.configTypeName }} {{ end }} {
     var c {{ $.configTypeName }}
+    {{ if $.returnError -}}
     err := {{ $applyFuncName }}(&c, options...)
     return c, err
+    {{- else -}}
+    {{ $applyFuncName }}(&c, options...)
+    return c
+    {{- end }}
 }
 {{ end }}
 
-func {{ $applyFuncName }}(c *{{ $.configTypeName }}, options ...{{ $.optionTypeName }}) error {
+func {{ $applyFuncName }}(c *{{ $.configTypeName }}, options ...{{ $.optionTypeName }}) {{ if $.returnError -}} error {{ end }} {
 {{- range .options -}}{{ $optionName := .Name }}{{ if .DefaultValue }}
     c.{{ .Name }} = {{ .DefaultValue }}
 {{- end }}{{ if .IsStruct }}{{ range .Fields }}{{ if .DefaultValue }}
     c.{{ $optionName }}.{{ .Name }} = {{ .DefaultValue }}
 {{- end }}{{ end }}
 {{- end }}{{ end }}
+{{ if $.returnError -}}
     for _, o := range options {
         if err := o.apply(c); err != nil {
             return err
             }
     }
     return nil
+{{- else -}}
+    for _, o := range options {
+        o.apply(c)
+    }
+{{- end }}
 }
 
 type {{ $.optionTypeName }} interface {
-    apply(*{{ $.configTypeName }}) error
+    apply(*{{ $.configTypeName }}) {{ if $.returnError -}} error {{ end }}
 }
 
 {{ range .options }}{{ $option := . }}
 
 {{ $name := .PublicName | ToPublic | printf "%s%s" $.optionPrefix }}
-{{ if $.optionSuffix }}{{ $name = $.optionSuffix | printf "%s%s" (.PublicName | ToPublic) }}{{ end  }}
+{{ if $.optionSuffix }}{{ $name = $.optionSuffix | printf "%s%s" (.PublicName | ToPublic) }}{{ end }}
 
 {{ $implName := $name | printf "%sImpl" | ToPrivate }}
 
@@ -66,7 +77,7 @@ type {{ $implName }} struct {
 {{- end }}
 }
 
-func (o {{ $implName }}) apply(c *{{ $.configTypeName }}) error {
+func (o {{ $implName }}) apply(c *{{ $.configTypeName }}) {{ if $.returnError -}} error {{ end }} {
 {{- if and $option.IsStruct $option.DefaultIsNil }}
     c.{{ $option.Name }} = new({{ $option.Type }})
 {{- end }}
@@ -75,7 +86,9 @@ func (o {{ $implName }}) apply(c *{{ $.configTypeName }}) error {
 {{- else }}
     c.{{ $option.Name }} = {{ if $option.DefaultIsNil }}&{{ end }}o.{{ .ParamName }}
 {{- end }}{{- end }}
+{{ if $.returnError -}}
     return nil
+{{- end }}
 }
 
 {{ if $.implementEqual -}}

test/golden/configWithNoError_options.go.txt

@@ -0,0 +1,60 @@
+package test
+
+// Code generated by github.com/launchdarkly/go-options.  DO NOT EDIT.
+
+import "fmt"
+
+import "github.com/google/go-cmp/cmp"
+
+type ApplyNoErrorOptionFunc func(c *configWithNoError)
+
+func (f ApplyNoErrorOptionFunc) apply(c *configWithNoError) {
+	f(c)
+}
+
+func newConfigWithNoError(options ...NoErrorOption) configWithNoError {
+	var c configWithNoError
+	applyConfigWithNoErrorOptions(&c, options...)
+	return c
+}
+
+func applyConfigWithNoErrorOptions(c *configWithNoError, options ...NoErrorOption) {
+	for _, o := range options {
+		o.apply(c)
+	}
+}
+
+type NoErrorOption interface {
+	apply(*configWithNoError)
+}
+
+type noErrorOptionMyIntImpl struct {
+	o int
+}
+
+func (o noErrorOptionMyIntImpl) apply(c *configWithNoError) {
+	c.myInt = o.o
+
+}
+
+func (o noErrorOptionMyIntImpl) Equal(v noErrorOptionMyIntImpl) bool {
+	switch {
+	case !cmp.Equal(o.o, v.o):
+		return false
+	}
+	return true
+}
+
+func (o noErrorOptionMyIntImpl) String() string {
+	name := "NoErrorOptionMyInt"
+
+	// hack to avoid go vet error about passing a function to Sprintf
+	var value interface{} = o.o
+	return fmt.Sprintf("%s: %+v", name, value)
+}
+
+func NoErrorOptionMyInt(o int) NoErrorOption {
+	return noErrorOptionMyIntImpl{
+		o: o,
+	}
+}

test/sample.go

@@ -88,3 +88,9 @@ type configWithoutCmp struct {
 type configWithoutStringer struct {
 	myInt int
 }
+
+
+//go:generate go-options -noerror=false -option NoErrorOption configWithNoError
+type configWithNoError struct {
+	myInt int
+}