Only generate moq when interface file is newer than output file

go.mod

@@ -1,4 +1,4 @@
-module github.com/matryer/moq
+module github.com/djui/moq
 
 go 1.18
 

internal/template/template.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 	"text/template"
 
-	"github.com/matryer/moq/internal/registry"
+	"github.com/djui/moq/internal/registry"
 )
 
 // Template is the Moq template. It is capable of generating the Moq

internal/template/template_data.go

@@ -5,7 +5,7 @@ import (
 	"go/types"
 	"strings"
 
-	"github.com/matryer/moq/internal/registry"
+	"github.com/djui/moq/internal/registry"
 )
 
 // Data is the template data used to render the Moq template.

internal/template/template_test.go

@@ -4,7 +4,7 @@ import (
 	"go/types"
 	"testing"
 
-	"github.com/matryer/moq/internal/registry"
+	"github.com/djui/moq/internal/registry"
 )
 
 func TestTemplateFuncs(t *testing.T) {

main.go

@@ -10,7 +10,7 @@ import (
 	"os"
 	"path/filepath"
 
-	"github.com/matryer/moq/pkg/moq"
+	"github.com/djui/moq/pkg/moq"
 )
 
 // Version is the command version, injected at build time.
@@ -23,6 +23,7 @@ type userFlags struct {
 	stubImpl   bool
 	skipEnsure bool
 	remove     bool
+	force      bool
 	args       []string
 }
 
@@ -37,6 +38,7 @@ func main() {
 	flag.BoolVar(&flags.skipEnsure, "skip-ensure", false,
 		"suppress mock implementation check, avoid import cycle if mocks generated outside of the tested package")
 	flag.BoolVar(&flags.remove, "rm", false, "first remove output file, if it exists")
+	flag.BoolVar(&flags.force, "force", false, "force generation, otherwise check if go generate file is newer than output file")
 
 	flag.Usage = func() {
 		fmt.Println(`moq [flags] source-dir interface [interface2 [interface3 [...]]]`)
@@ -65,6 +67,19 @@ func run(flags userFlags) error {
 		return errors.New("not enough arguments")
 	}
 
+	if !flags.force && flags.outFile != "" {
+		inFile := os.Getenv("GOFILE")
+		if inStat, err := os.Stat(inFile); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+		} else if outStat, err := os.Stat(flags.outFile); err != nil {
+			if !errors.Is(err, os.ErrNotExist) {
+				fmt.Fprintln(os.Stderr, err)
+			}
+		} else if !inStat.ModTime().After(outStat.ModTime()) {
+			return nil // Assume no changes thus no need to regenerate.
+		}
+	}
+
 	if flags.remove && flags.outFile != "" {
 		if err := os.Remove(flags.outFile); err != nil {
 			if !errors.Is(err, os.ErrNotExist) {

pkg/moq/moq.go

@@ -8,8 +8,8 @@ import (
 	"io"
 	"strings"
 
-	"github.com/matryer/moq/internal/registry"
-	"github.com/matryer/moq/internal/template"
+	"github.com/djui/moq/internal/registry"
+	"github.com/djui/moq/internal/template"
 )
 
 // Mocker can generate mock structs.