Generics support (#4)

* generics support

* bump golangci-lint to 1.54

* address comments

* ok i see why ElementsMatch

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Run linters
         uses: golangci/golangci-lint-action@v2
         with:
-          version: v1.52
+          version: v1.54
 
   test:
     strategy:

go.mod

@@ -3,7 +3,7 @@ module github.com/clear-street/reinforcer
 go 1.20
 
 require (
-	github.com/dave/jennifer v1.4.1
+	github.com/dave/jennifer v1.7.0
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/pkg/errors v0.9.1
 	github.com/rs/zerolog v1.29.0

go.sum

@@ -57,8 +57,8 @@ github.com/cncf/udpa/go v0.0.0-20200629203442-efcf912fb354/go.mod h1:WmhPx2Nbnht
 github.com/cncf/udpa/go v0.0.0-20201120205902-5459f2c99403/go.mod h1:WmhPx2Nbnhtbo57+VJT5O0JRkEi1Wbu0z5j0R8u5Hbk=
 github.com/coreos/go-systemd/v22 v22.3.3-0.20220203105225-a9a7ef127534/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
-github.com/dave/jennifer v1.4.1 h1:XyqG6cn5RQsTj3qlWQTKlRGAyrTcsk1kUmWdZBzRjDw=
-github.com/dave/jennifer v1.4.1/go.mod h1:7jEdnm+qBcxl8PC0zyp7vxcpSRnzXSt9r39tpTVGlwA=
+github.com/dave/jennifer v1.7.0 h1:uRbSBH9UTS64yXbh4FrMHfgfY762RD+C7bUPKODpSJE=
+github.com/dave/jennifer v1.7.0/go.mod h1:nXbxhEmQfOZhWml3D1cDK5M1FLnMSozpbFN/m3RmGZc=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=

internal/generator/executor/executor.go

@@ -111,7 +111,7 @@ func createFileConfigs(discoveredSet map[string]struct{}, match map[string]*load
 			return nil, errors.Errorf("multiple types with same name discovered with name %s", typName)
 		}
 		discoveredSet[typName] = struct{}{}
-		cfg = append(cfg, generator.NewFileConfig(typName, typName, res.Methods))
+		cfg = append(cfg, generator.NewFileConfig(typName, typName, res.TypeParams, res.TypeArgs, res.Methods))
 	}
 	return cfg, nil
 }

internal/generator/generator.go

@@ -21,12 +21,16 @@ type FileConfig struct {
 	srcTypeName string
 	// outTypeName is the desired output type name
 	outTypeName string
+	// typeParams is the list of generic type parameters
+	typeParams []jen.Code
+	// typeArgs is the list of generic type arguments
+	typeArgs []jen.Code
 	// methods that should be in the generated type
 	methods []*method.Method
 }
 
 // NewFileConfig creates a new instance of the FileConfig which holds code generation configuration
-func NewFileConfig(srcTypeName, outTypeName string, methods []*method.Method) *FileConfig {
+func NewFileConfig(srcTypeName, outTypeName string, typeParams []jen.Code, typeArgs []jen.Code, methods []*method.Method) *FileConfig {
 	// cannot use cases.Title as it will lowercase MyService to Myservice
 	if len(srcTypeName) > 0 {
 		srcTypeName = strings.ToUpper(string(srcTypeName[0])) + srcTypeName[1:]
@@ -37,6 +41,8 @@ func NewFileConfig(srcTypeName, outTypeName string, methods []*method.Method) *F
 	return &FileConfig{
 		srcTypeName: srcTypeName,
 		outTypeName: outTypeName,
+		typeParams:  typeParams,
+		typeArgs:    typeArgs,
 		methods:     methods,
 	}
 }
@@ -136,22 +142,22 @@ func generateFile(outPkg string, ignoreNoReturnMethods bool, fileCfg *FileConfig
 	for _, meth := range methods {
 		declMethods = append(declMethods, jen.Id(meth.Name).Params(meth.ParametersNameAndType...).Params(meth.ReturnTypes...))
 	}
-	f.Add(jen.Type().Id(fileCfg.targetName()).Interface(
+	f.Add(jen.Type().Id(fileCfg.targetName()).Types(fileCfg.typeParams...).Interface(
 		declMethods...,
 	))
 
 	// Declare the proxy implementation
-	f.Add(jen.Type().Id(fileCfg.outTypeName).Struct(
+	f.Add(jen.Type().Id(fileCfg.outTypeName).Types(fileCfg.typeParams...).Struct(
 		jen.Op("*").Id("base"),
-		jen.Id("delegate").Id(fileCfg.targetName()),
+		jen.Id("delegate").Id(fileCfg.targetName()).Types(fileCfg.typeArgs...),
 	))
 
 	// Declare the ctor
-	f.Add(jen.Func().Id("New"+fileCfg.outTypeName).Params(
-		jen.Id("delegate").Id(fileCfg.targetName()),
+	f.Add(jen.Func().Id("New"+fileCfg.outTypeName).Types(fileCfg.typeParams...).Params(
+		jen.Id("delegate").Id(fileCfg.targetName()).Types(fileCfg.typeArgs...),
 		jen.Id("runnerFactory").Id("runnerFactory"),
 		jen.Id("options").Op("...").Id("Option"),
-	).Op("*").Id(fileCfg.outTypeName).Block(
+	).Op("*").Id(fileCfg.outTypeName).Types(fileCfg.typeArgs...).Block(
 		// if delegate == nil
 		jen.If(jen.Id("delegate").Op("==").Nil().Block(
 			// panic("...")
@@ -163,7 +169,7 @@ func generateFile(outPkg string, ignoreNoReturnMethods bool, fileCfg *FileConfig
 			jen.Panic(jen.Lit("provided nil runner factory")),
 		)),
 		// c:= &OutTypeName{...}
-		jen.Id("c").Op(":=").Add(jen.Op("&").Id(fileCfg.outTypeName).Values(jen.Dict{
+		jen.Id("c").Op(":=").Add(jen.Op("&").Id(fileCfg.outTypeName).Types(fileCfg.typeArgs...).Values(jen.Dict{
 			// embed the base struct
 			jen.Id("base"): jen.Op("&").Id("base").Values(jen.Dict{
 				jen.Id("errorPredicate"): jen.Id("RetryAllErrors"),
@@ -181,7 +187,7 @@ func generateFile(outPkg string, ignoreNoReturnMethods bool, fileCfg *FileConfig
 	// Declare all of our proxy methods
 	for _, mm := range methods {
 		if mm.ReturnsError {
-			r := retryable.NewRetryable(mm, fileCfg.outTypeName, fileCfg.receiverName())
+			r := retryable.NewRetryable(mm, fileCfg.outTypeName, fileCfg.typeArgs, fileCfg.receiverName())
 			s, err := r.Statement()
 			if err != nil {
 				return "", err
@@ -190,9 +196,9 @@ func generateFile(outPkg string, ignoreNoReturnMethods bool, fileCfg *FileConfig
 		} else {
 			var p statement
 			if ignoreNoReturnMethods {
-				p = passthrough.NewPassThrough(mm, fileCfg.outTypeName, fileCfg.receiverName())
+				p = passthrough.NewPassThrough(mm, fileCfg.outTypeName, fileCfg.typeArgs, fileCfg.receiverName())
 			} else {
-				p = noret.NewNoReturn(mm, fileCfg.outTypeName, fileCfg.receiverName())
+				p = noret.NewNoReturn(mm, fileCfg.outTypeName, fileCfg.typeArgs, fileCfg.receiverName())
 			}
 			s, err := p.Statement()
 			if err != nil {

internal/generator/generator_test.go

@@ -880,6 +880,128 @@ func (g *GeneratedService) SayHello(arg0 string) error {
 	}
 	return err
 }
+`,
+					},
+				},
+			},
+		},
+		{
+			name:                  "Generic Type Parameters",
+			ignoreNoReturnMethods: true,
+			inputs: map[string]input{
+				"users_service.go": {
+					interfaceName: "Service",
+					code: `package fake
+
+type Service[T any] interface {
+	SayHello(name T) error
+	DoNothing()
+}
+`,
+				},
+			},
+			outCode: &generator.Generated{
+				Common: `// Code generated by reinforcer, DO NOT EDIT.
+
+package resilient
+
+import (
+	"context"
+	goresilience "github.com/slok/goresilience"
+)
+
+type base struct {
+	errorPredicate func(string, error) bool
+	runnerFactory  runnerFactory
+}
+type runnerFactory interface {
+	GetRunner(name string) goresilience.Runner
+}
+
+var RetryAllErrors = func(_ string, _ error) bool {
+	return true
+}
+
+type Option func(*base)
+
+func WithRetryableErrorPredicate(fn func(string, error) bool) Option {
+	return func(o *base) {
+		o.errorPredicate = fn
+	}
+}
+func (b *base) run(ctx context.Context, name string, fn func(ctx context.Context) error) error {
+	return b.runnerFactory.GetRunner(name).Run(ctx, fn)
+}
+`,
+				Constants: `// Code generated by reinforcer, DO NOT EDIT.
+
+package resilient
+
+// GeneratedServiceMethods are the methods in GeneratedService
+var GeneratedServiceMethods = struct {
+	DoNothing string
+	SayHello  string
+}{
+	DoNothing: "DoNothing",
+	SayHello:  "SayHello",
+}
+`,
+				Files: []*generator.GeneratedFile{
+					{
+						TypeName: "GeneratedService",
+						Contents: `// Code generated by reinforcer, DO NOT EDIT.
+
+package resilient
+
+import "context"
+
+type targetService[T any] interface {
+	DoNothing()
+	SayHello(arg0 T) error
+}
+type GeneratedService[T any] struct {
+	*base
+	delegate targetService[T]
+}
+
+func NewGeneratedService[T any](delegate targetService[T], runnerFactory runnerFactory, options ...Option) *GeneratedService[T] {
+	if delegate == nil {
+		panic("provided nil delegate")
+	}
+	if runnerFactory == nil {
+		panic("provided nil runner factory")
+	}
+	c := &GeneratedService[T]{
+		base: &base{
+			errorPredicate: RetryAllErrors,
+			runnerFactory:  runnerFactory,
+		},
+		delegate: delegate,
+	}
+	for _, o := range options {
+		o(c.base)
+	}
+	return c
+}
+func (g *GeneratedService[T]) DoNothing() {
+	g.delegate.DoNothing()
+}
+func (g *GeneratedService[T]) SayHello(arg0 T) error {
+	var nonRetryableErr error
+	err := g.run(context.Background(), GeneratedServiceMethods.SayHello, func(_ context.Context) error {
+		var err error
+		err = g.delegate.SayHello(arg0)
+		if g.errorPredicate(GeneratedServiceMethods.SayHello, err) {
+			return err
+		}
+		nonRetryableErr = err
+		return nil
+	})
+	if nonRetryableErr != nil {
+		return nonRetryableErr
+	}
+	return err
+}
 `,
 					},
 				},
@@ -947,6 +1069,8 @@ func loadInterface(t *testing.T, filesCode map[string]input) []*generator.FileCo
 		}
 		loadedTypes = append(loadedTypes, generator.NewFileConfig(in.interfaceName,
 			fmt.Sprintf("Generated%s", in.interfaceName),
+			svc.TypeParams,
+			svc.TypeArgs,
 			svc.Methods,
 		))
 	}