Add option to omit empty/nil variadic slice when unroll-variadic is false

cmd/mockery.go

@@ -75,6 +75,7 @@ func NewRootCmd() *cobra.Command {
 	pFlags.Bool("disable-version-string", false, "Do not insert the version string into the generated mock file.")
 	pFlags.String("boilerplate-file", "", "File to read a boilerplate text from. Text should be a go block comment, i.e. /* ... */")
 	pFlags.Bool("unroll-variadic", true, "For functions with variadic arguments, do not unroll the arguments into the underlying testify call. Instead, pass variadic slice as-is.")
+	pFlags.Bool("omit-empty-rolled-variadic", false, "For functions with variadic arguments, omit passing empty slice to underlying testify call. Used in tandem with unroll-variadic set to false.")
 	pFlags.Bool("exported", false, "Generates public mocks for private interfaces.")
 	pFlags.Bool("with-expecter", false, "Generate expecter utility around mock's On, Run and Return methods with explicit types. This option is NOT compatible with -unroll-variadic=false")
 	pFlags.StringArray("replace-type", nil, "Replace types")
@@ -380,18 +381,19 @@ func (r *RootApp) Run() error {
 		}
 
 		visitor := pkg.NewGeneratorVisitor(pkg.GeneratorVisitorConfig{
-			Boilerplate:          boilerplate,
-			DisableVersionString: r.Config.DisableVersionString,
-			Exported:             r.Config.Exported,
-			InPackage:            r.Config.InPackage,
-			KeepTree:             r.Config.KeepTree,
-			Note:                 r.Config.Note,
-			PackageName:          r.Config.Outpkg,
-			PackageNamePrefix:    r.Config.Packageprefix,
-			StructName:           r.Config.StructName,
-			UnrollVariadic:       r.Config.UnrollVariadic,
-			WithExpecter:         r.Config.WithExpecter,
-			ReplaceType:          r.Config.ReplaceType,
+			Boilerplate:             boilerplate,
+			DisableVersionString:    r.Config.DisableVersionString,
+			Exported:                r.Config.Exported,
+			InPackage:               r.Config.InPackage,
+			KeepTree:                r.Config.KeepTree,
+			Note:                    r.Config.Note,
+			PackageName:             r.Config.Outpkg,
+			PackageNamePrefix:       r.Config.Packageprefix,
+			StructName:              r.Config.StructName,
+			UnrollVariadic:          r.Config.UnrollVariadic,
+			OmitEmptyRolledVariadic: r.Config.OmitEmptyRolledVariadic,
+			WithExpecter:            r.Config.WithExpecter,
+			ReplaceType:             r.Config.ReplaceType,
 		}, osp, r.Config.DryRun)
 
 		generated := walker.Walk(ctx, visitor)

pkg/config/config.go

@@ -60,12 +60,13 @@ type Config struct {
 	BoilerplateFile      string                 `mapstructure:"boilerplate-file"`
 	// StructName overrides the name given to the mock struct and should only be nonempty
 	// when generating for an exact match (non regex expression in -name).
-	StructName     string   `mapstructure:"structname"`
-	TestOnly       bool     `mapstructure:"testonly"`
-	UnrollVariadic bool     `mapstructure:"unroll-variadic"`
-	Version        bool     `mapstructure:"version"`
-	WithExpecter   bool     `mapstructure:"with-expecter"`
-	ReplaceType    []string `mapstructure:"replace-type"`
+	StructName              string   `mapstructure:"structname"`
+	TestOnly                bool     `mapstructure:"testonly"`
+	UnrollVariadic          bool     `mapstructure:"unroll-variadic"`
+	OmitEmptyRolledVariadic bool     `mapstructure:"omit-empty-rolled-variadic"`
+	Version                 bool     `mapstructure:"version"`
+	WithExpecter            bool     `mapstructure:"with-expecter"`
+	ReplaceType             []string `mapstructure:"replace-type"`
 
 	// Viper throws away case-sensitivity when it marshals into this struct. This
 	// destroys necessary information we need, specifically around interface names.

pkg/generator.go

@@ -50,18 +50,19 @@ func DetermineOutputPackageName(
 }
 
 type GeneratorConfig struct {
-	Boilerplate          string
-	DisableVersionString bool
-	Exported             bool
-	InPackage            bool
-	KeepTree             bool
-	Note                 string
-	PackageName          string
-	PackageNamePrefix    string
-	StructName           string
-	UnrollVariadic       bool
-	WithExpecter         bool
-	ReplaceType          []string
+	Boilerplate             string
+	DisableVersionString    bool
+	Exported                bool
+	InPackage               bool
+	KeepTree                bool
+	Note                    string
+	PackageName             string
+	PackageNamePrefix       string
+	StructName              string
+	UnrollVariadic          bool
+	OmitEmptyRolledVariadic bool
+	WithExpecter            bool
+	ReplaceType             []string
 }
 
 // Generator is responsible for generating the string containing
@@ -938,7 +939,16 @@ func {{ .ConstructorName }}{{ .TypeConstraint }}(t {{ .ConstructorTestingInterfa
 func (g *Generator) generateCalled(list *paramList) (preamble string, called string) {
 	namesLen := len(list.Names)
 	if namesLen == 0 || !list.Variadic || !g.config.UnrollVariadic {
-		called = "_m.Called(" + strings.Join(list.Names, ", ") + ")"
+		if !g.config.OmitEmptyRolledVariadic {
+			called = "_m.Called(" + strings.Join(list.Names, ", ") + ")"
+			return
+		}
+
+		variadicName := list.Names[namesLen-1]
+		tmpRet := resolveCollision(list.Names, "tmpRet")
+
+		preamble = fmt.Sprintf("\n\tvar " + tmpRet + " mock.Arguments\n\tif len(" + variadicName + ") > 0 {\n\t\t" + tmpRet + " = _m.Called(" + strings.Join(list.Names, ", ") + ")\n\t} else {\n\t\t" + tmpRet + " = _m.Called(" + strings.Join(list.Names[:len(list.Names)-1], ", ") + ")\n\t}\n\n\t")
+		called = tmpRet
 		return
 	}
 

pkg/generator_test.go

@@ -1566,6 +1566,34 @@ func (s *GeneratorSuite) TestGeneratorVariadicArgsAsOneArg() {
 	)
 }
 
+func (s *GeneratorSuite) TestGeneratorVariadicArgsOmitEmpty() {
+	expectedBytes, err := os.ReadFile(getMocksPath("RequesterVariadicOmitEmpty.go"))
+	s.NoError(err)
+	expected := string(expectedBytes)
+	expected = expected[strings.Index(expected, "// RequesterVariadicOmitEmpty is"):]
+	generator := NewGenerator(
+		s.ctx, GeneratorConfig{
+			StructName:              "RequesterVariadicOmitEmpty",
+			InPackage:               true,
+			UnrollVariadic:          false,
+			OmitEmptyRolledVariadic: true,
+		}, s.getInterfaceFromFile("requester_variadic.go", "RequesterVariadic"), pkg,
+	)
+	s.NoError(generator.Generate(s.ctx), "The generator ran without errors.")
+
+	var actual []byte
+	actual, fmtErr := format.Source(generator.buf.Bytes())
+	s.NoError(fmtErr, "The formatter ran without errors.")
+
+	expectedLines := strings.Split(expected, "\n")
+	actualLines := strings.Split(string(actual), "\n")
+
+	s.Equal(
+		expectedLines, actualLines,
+		"The generator produced unexpected output.",
+	)
+}
+
 func TestRequesterVariadicOneArgument(t *testing.T) {
 	t.Run("Get \"1\", \"2\", \"3\"", func(t *testing.T) {
 		m := mocks.RequesterVariadicOneArgument{}

pkg/outputter.go

@@ -271,18 +271,19 @@ func (m *Outputter) Generate(ctx context.Context, iface *Interface) error {
 		}
 
 		g := GeneratorConfig{
-			Boilerplate:          m.boilerplate,
-			DisableVersionString: interfaceConfig.DisableVersionString,
-			Exported:             interfaceConfig.Exported,
-			InPackage:            interfaceConfig.InPackage,
-			KeepTree:             interfaceConfig.KeepTree,
-			Note:                 interfaceConfig.Note,
-			PackageName:          interfaceConfig.Outpkg,
-			PackageNamePrefix:    interfaceConfig.Packageprefix,
-			StructName:           interfaceConfig.MockName,
-			UnrollVariadic:       interfaceConfig.UnrollVariadic,
-			WithExpecter:         interfaceConfig.WithExpecter,
-			ReplaceType:          interfaceConfig.ReplaceType,
+			Boilerplate:             m.boilerplate,
+			DisableVersionString:    interfaceConfig.DisableVersionString,
+			Exported:                interfaceConfig.Exported,
+			InPackage:               interfaceConfig.InPackage,
+			KeepTree:                interfaceConfig.KeepTree,
+			Note:                    interfaceConfig.Note,
+			PackageName:             interfaceConfig.Outpkg,
+			PackageNamePrefix:       interfaceConfig.Packageprefix,
+			StructName:              interfaceConfig.MockName,
+			UnrollVariadic:          interfaceConfig.UnrollVariadic,
+			OmitEmptyRolledVariadic: interfaceConfig.OmitEmptyRolledVariadic,
+			WithExpecter:            interfaceConfig.WithExpecter,
+			ReplaceType:             interfaceConfig.ReplaceType,
 		}
 		generator := NewGenerator(ctx, g, iface, "")
 

pkg/walker.go

@@ -121,12 +121,13 @@ type GeneratorVisitorConfig struct {
 	KeepTree             bool
 	Note                 string
 	// The name of the output package, if InPackage is false (defaults to "mocks")
-	PackageName       string
-	PackageNamePrefix string
-	StructName        string
-	UnrollVariadic    bool
-	WithExpecter      bool
-	ReplaceType       []string
+	PackageName             string
+	PackageNamePrefix       string
+	StructName              string
+	UnrollVariadic          bool
+	OmitEmptyRolledVariadic bool
+	WithExpecter            bool
+	ReplaceType             []string
 }
 
 type GeneratorVisitor struct {
@@ -175,18 +176,19 @@ func (v *GeneratorVisitor) VisitWalk(ctx context.Context, iface *Interface) erro
 	}()
 
 	generatorConfig := GeneratorConfig{
-		Boilerplate:          v.config.Boilerplate,
-		DisableVersionString: v.config.DisableVersionString,
-		Exported:             v.config.Exported,
-		InPackage:            v.config.InPackage,
-		KeepTree:             v.config.KeepTree,
-		Note:                 v.config.Note,
-		PackageName:          v.config.PackageName,
-		PackageNamePrefix:    v.config.PackageNamePrefix,
-		StructName:           v.config.StructName,
-		UnrollVariadic:       v.config.UnrollVariadic,
-		WithExpecter:         v.config.WithExpecter,
-		ReplaceType:          v.config.ReplaceType,
+		Boilerplate:             v.config.Boilerplate,
+		DisableVersionString:    v.config.DisableVersionString,
+		Exported:                v.config.Exported,
+		InPackage:               v.config.InPackage,
+		KeepTree:                v.config.KeepTree,
+		Note:                    v.config.Note,
+		PackageName:             v.config.PackageName,
+		PackageNamePrefix:       v.config.PackageNamePrefix,
+		StructName:              v.config.StructName,
+		UnrollVariadic:          v.config.UnrollVariadic,
+		OmitEmptyRolledVariadic: v.config.OmitEmptyRolledVariadic,
+		WithExpecter:            v.config.WithExpecter,
+		ReplaceType:             v.config.ReplaceType,
 	}
 
 	gen := NewGenerator(ctx, generatorConfig, iface, "")