☠️ Fix bones for recursive message types (#42)

Fix `jig bones` for recursive message types so that it doesn't cause an
infinite recursion:

	runtime: goroutine stack exceeds 1000000000-byte limit

Add a stack to the formatter tracking the the message names. Rename
FormatOptions to Formatter to better reflect the carried state and type
alias it back to FormatOptions for compatibility and external use.

Pull-Request: #42

Makefile

@@ -12,8 +12,8 @@ all: build test check-coverage lint lint-proto ## build, test, check coverage an
 
 ci: clean check-uptodate all  ## Full clean build and up-to-date checks as run on CI
 
-check-uptodate: proto tidy
-	test -z "$$(git status --porcelain -- go.mod go.sum '*.pb')" || { git status; false; }
+check-uptodate: proto golden tidy
+	test -z "$$(git status --porcelain -- go.mod go.sum '*.pb' '*.jsonnet' '*.js')" || { git status; false; }
 
 clean::  ## Remove generated files
 	-rm -rf $(O)
@@ -49,7 +49,7 @@ cover: test  ## Show test coverage in your browser
 	go tool cover -html=$(COVERFILE)
 
 RUN_BONES = $(O)/jig bones --force --language=$(1) --quote-style=$(2) --proto-set pb/$(3)/$(4) --method-dir bones/testdata/golden/$(3)-$(2)
-golden: build  ## Generate golden test files
+golden: build proto  ## Generate golden test files
 	$(call RUN_BONES,jsonnet,double,exemplar,exemplar.pb)
 	$(call RUN_BONES,jsonnet,double,greet,greeter.pb)
 	$(call RUN_BONES,jsonnet,single,exemplar,exemplar.pb)

bones/exemplar.go

@@ -4,23 +4,28 @@ import (
 	"fmt"
 	"strings"
 
+	"golang.org/x/exp/slices"
 	"google.golang.org/protobuf/reflect/protoreflect"
 )
 
-// FormatOptions is a configurable target language exemplar generator.
-type FormatOptions struct {
+// Formatter is a configurable target language exemplar generator.
+type Formatter struct {
 	Lang       Lang
 	QuoteStyle QuoteStyle
+
+	messageStack []protoreflect.FullName
 }
 
+type FormatOptions = Formatter
+
 // Return the file extension for the given language.
-func (o *FormatOptions) Extension() string {
-	return "." + o.Lang.String()
+func (f *Formatter) Extension() string {
+	return "." + f.Lang.String()
 }
 
 // Return the file extension for the given language.
-func (o *FormatOptions) quote(s string) string {
-	if o.QuoteStyle == Double {
+func (f *Formatter) quote(s string) string {
+	if f.QuoteStyle == Double {
 		return `"` + s + `"`
 	}
 	return `'` + s + `'`
@@ -29,9 +34,9 @@ func (o *FormatOptions) quote(s string) string {
 // MethodExemplar returns an exemplar for a method, with an exemplar for the
 // input message as a comment and a function returning an exemplar of the
 // output message as the method implementation.
-func (o *FormatOptions) MethodExemplar(md protoreflect.MethodDescriptor) exemplar {
+func (f *Formatter) MethodExemplar(md protoreflect.MethodDescriptor) exemplar {
 	// Format the input message exemplar as a comment
-	ime := o.MessageExemplar(md.Input())
+	ime := f.MessageExemplar(md.Input())
 	ime.append(",")
 	if md.IsStreamingClient() && !md.IsStreamingServer() {
 		ime.nest("stream: [", "],")
@@ -42,14 +47,14 @@ func (o *FormatOptions) MethodExemplar(md protoreflect.MethodDescriptor) exempla
 	ime.prefix("// ")
 
 	// Format the output message exemplar
-	ome := o.MessageExemplar(md.Output())
+	ome := f.MessageExemplar(md.Output())
 	ome.append(",")
 	if md.IsStreamingServer() {
 		ome.nest("stream: [", "],")
 	} else {
 		ome.prepend("response: ")
 	}
-	if o.Lang == Jsonnet {
+	if f.Lang == Jsonnet {
 		ome.nest("function(input) {", "}")
 	} else {
 		ome.nest("return {", "}")
@@ -83,23 +88,30 @@ func (o *FormatOptions) MethodExemplar(md protoreflect.MethodDescriptor) exempla
 // with a field for every message field. Each field value is an exemplar of the
 // type of the field. Oneof fields are emitted as comments as a message should
 // not have more than one oneof specified.
-func (o *FormatOptions) MessageExemplar(md protoreflect.MessageDescriptor) exemplar {
+func (f *Formatter) MessageExemplar(md protoreflect.MessageDescriptor) exemplar {
 	var e exemplar
 
 	if strings.HasPrefix(string(md.FullName()), "google.protobuf.") {
-		if e = o.WellKnownExemplar(md); len(e.lines) > 0 {
+		if e = f.WellKnownExemplar(md); len(e.lines) > 0 {
 			return e
 		}
 	}
 
+	if slices.Contains(f.messageStack, md.FullName()) {
+		e.line("{}")
+		return e
+	}
+
+	f.messageStack = append(f.messageStack, md.FullName())
 	for _, fd := range fields(md) {
-		fe := o.FieldExemplar(fd)
+		fe := f.FieldExemplar(fd)
 		if fd.ContainingOneof() != nil {
 			// Comment out one-of fields since they should not all be present.
 			fe.prefix("// ")
 		}
 		e.extend(fe)
 	}
+	f.messageStack = f.messageStack[:len(f.messageStack)-1]
 
 	e.nest("{", "}")
 	return e
@@ -110,52 +122,52 @@ func (o *FormatOptions) MessageExemplar(md protoreflect.MessageDescriptor) exemp
 // JSON as a single field, rather than as an object.
 //
 // https://developers.google.com/protocol-buffers/docs/reference/google.protobuf
-func (o *FormatOptions) WellKnownExemplar(md protoreflect.MessageDescriptor) exemplar {
+func (f *Formatter) WellKnownExemplar(md protoreflect.MessageDescriptor) exemplar {
 	var e exemplar
 	switch string(md.Name()) {
 	case "Api", "Enum", "EnumValue", "Field", "Method", "Mixin", "Option", "SourceContext", "Type":
 		return e // empty exemplar. will be formatted as a message
 	case "Any":
 		// Emit an Any that can be read back in without modification
 		// Duration chosen at random, almost. Also for its simplicity.
-		e.line(o.quote("@type") + ": " + o.quote("type.googleapis.com/google.protobuf.Duration") + ",")
-		e.line("value: " + o.quote("0s") + ",")
+		e.line(f.quote("@type") + ": " + f.quote("type.googleapis.com/google.protobuf.Duration") + ",")
+		e.line("value: " + f.quote("0s") + ",")
 		e.nest("{", "}")
 	case "BoolValue", "BytesValue", "DoubleValue", "FloatValue",
 		"Int32Value", "Int64Value", "StringValue", "UInt32Value", "UInt64Value":
-		return o.FieldValueExemplar(md.Fields().ByName("value"))
+		return f.FieldValueExemplar(md.Fields().ByName("value"))
 	case "Duration":
-		e.line(o.quote("0s"))
+		e.line(f.quote("0s"))
 	case "Empty":
 		e.line("{}")
 	case "FieldMask":
-		e.line(o.quote("field1.field2,field3"))
+		e.line(f.quote("field1.field2,field3"))
 	case "ListValue":
-		return o.FieldValueExemplar(md.Fields().ByName("values"))
+		return f.FieldValueExemplar(md.Fields().ByName("values"))
 	case "Struct":
-		e = o.FieldValueExemplar(md.Fields().Get(0).MapValue())
+		e = f.FieldValueExemplar(md.Fields().Get(0).MapValue())
 		e.prepend("structField: ")
 		e.append(",")
 		e.nest("{", "}")
 	case "Timestamp":
-		e.line(o.quote("2006-01-02T15:04:05.999999999Z"))
+		e.line(f.quote("2006-01-02T15:04:05.999999999Z"))
 	case "Value":
-		e.line(o.quote("https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#value"))
+		e.line(f.quote("https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#value"))
 	}
 	return e
 }
 
 // FieldExemplar returns an exemplar for a message field. It has the JSON name
 // for the field prefixed and a comment appended to the first line describing
 // the type of the field.
-func (o *FormatOptions) FieldExemplar(fd protoreflect.FieldDescriptor) exemplar {
-	e := o.FieldValueExemplar(fd)
+func (f *Formatter) FieldExemplar(fd protoreflect.FieldDescriptor) exemplar {
+	e := f.FieldValueExemplar(fd)
 	e.prepend(fd.JSONName() + ": ")
 	e.append(",")
 
 	// Add a description of the type to the end of the first line of the
 	// exemplar as a comment. If part of a oneof, name the oneof too.
-	if desc := o.typeDescription(fd); desc != "" {
+	if desc := f.typeDescription(fd); desc != "" {
 		if od := fd.ContainingOneof(); od != nil {
 			desc += " (one-of " + string(od.Name()) + ")"
 		}
@@ -174,15 +186,15 @@ func (o *FormatOptions) FieldExemplar(fd protoreflect.FieldDescriptor) exemplar
 //
 // Repeated fields are emitted with a single element exemplar of the repeated
 // type.
-func (o *FormatOptions) FieldValueExemplar(fd protoreflect.FieldDescriptor) exemplar {
+func (f *Formatter) FieldValueExemplar(fd protoreflect.FieldDescriptor) exemplar {
 	var e exemplar
 	switch fd.Kind() {
 	case protoreflect.EnumKind:
-		e = o.EnumExemplar(fd)
+		e = f.EnumExemplar(fd)
 	case protoreflect.MessageKind, protoreflect.GroupKind:
-		e = o.MessageExemplar(fd.Message())
+		e = f.MessageExemplar(fd.Message())
 	default:
-		e = o.ScalarExemplar(fd.Kind())
+		e = f.ScalarExemplar(fd.Kind())
 	}
 
 	if fd.Cardinality() == protoreflect.Repeated {
@@ -198,7 +210,7 @@ func (o *FormatOptions) FieldValueExemplar(fd protoreflect.FieldDescriptor) exem
 // Enum exemplars are emitted as a string with the name of the second enum if
 // there is more than one enum value, otherwise the first enum. The second enum
 // is preferred as often the first enum is the "invalid" value for that enum.
-func (o *FormatOptions) EnumExemplar(fd protoreflect.FieldDescriptor) exemplar {
+func (f *Formatter) EnumExemplar(fd protoreflect.FieldDescriptor) exemplar {
 	var e exemplar
 	if fd.Kind() != protoreflect.EnumKind {
 		return e
@@ -215,13 +227,13 @@ func (o *FormatOptions) EnumExemplar(fd protoreflect.FieldDescriptor) exemplar {
 	if ev.Len() > 1 {
 		name = ev.Get(1).Name()
 	}
-	e.line(o.quote(string(name)))
+	e.line(f.quote(string(name)))
 	return e
 }
 
 // ScalarExemplar returns an exemplar with a value for basic kinds that have a
 // single value (scalars). An empty exemplar is returned for other kinds.
-func (o *FormatOptions) ScalarExemplar(kind protoreflect.Kind) exemplar {
+func (f *Formatter) ScalarExemplar(kind protoreflect.Kind) exemplar {
 	var e exemplar
 	switch kind {
 	case protoreflect.BoolKind:
@@ -234,22 +246,25 @@ func (o *FormatOptions) ScalarExemplar(kind protoreflect.Kind) exemplar {
 	case protoreflect.FloatKind, protoreflect.DoubleKind:
 		e.line("0.0")
 	case protoreflect.StringKind, protoreflect.BytesKind:
-		e.line(o.quote(""))
+		e.line(f.quote(""))
 	}
 	return e
 }
 
 // typeDescription returns a string description of a field's type.
-func (o *FormatOptions) typeDescription(fd protoreflect.FieldDescriptor) string {
+func (f *Formatter) typeDescription(fd protoreflect.FieldDescriptor) string {
 	if fd.IsMap() {
-		return fmt.Sprintf("map<%s, %s>", o.typeDescription(fd.MapKey()), o.typeDescription(fd.MapValue()))
+		return fmt.Sprintf("map<%s, %s>", f.typeDescription(fd.MapKey()), f.typeDescription(fd.MapValue()))
 	}
 	result := ""
 	switch fd.Kind() {
 	case protoreflect.EnumKind:
 		result = string(fd.Enum().Name())
 	case protoreflect.MessageKind, protoreflect.GroupKind:
 		result = string(fd.Message().Name())
+		if slices.Contains(f.messageStack, fd.Message().FullName()) {
+			result += " (recursive)"
+		}
 	case protoreflect.BoolKind,
 		protoreflect.Int32Kind, protoreflect.Sint32Kind, protoreflect.Uint32Kind,
 		protoreflect.Int64Kind, protoreflect.Sint64Kind, protoreflect.Uint64Kind,

bones/generate.go

@@ -15,7 +15,7 @@ import (
 // slice. Method exemplars are written to stdout if methodDir is empty,
 // otherwise each method is written to a separate file in that directory.
 // Existing files will not be overwritten unless force is true.
-func Generate(fds *descriptorpb.FileDescriptorSet, methodDir string, force bool, targets []string, formatter FormatOptions) error {
+func Generate(fds *descriptorpb.FileDescriptorSet, methodDir string, force bool, targets []string, formatter Formatter) error {
 	files, err := protodesc.NewFiles(fds)
 	if err != nil {
 		return err
@@ -29,7 +29,7 @@ func Generate(fds *descriptorpb.FileDescriptorSet, methodDir string, force bool,
 	return err
 }
 
-func genFile(fd protoreflect.FileDescriptor, methodDir string, force bool, targets []string, formatter FormatOptions) error {
+func genFile(fd protoreflect.FileDescriptor, methodDir string, force bool, targets []string, formatter Formatter) error {
 	for _, sd := range services(fd) {
 		for _, md := range methods(sd) {
 			if err := genMethod(md, methodDir, force, targets, formatter); err != nil {
@@ -40,7 +40,7 @@ func genFile(fd protoreflect.FileDescriptor, methodDir string, force bool, targe
 	return nil
 }
 
-func genMethod(md protoreflect.MethodDescriptor, methodDir string, force bool, targets []string, formatter FormatOptions) error {
+func genMethod(md protoreflect.MethodDescriptor, methodDir string, force bool, targets []string, formatter Formatter) error {
 	var err error
 	if !match(md, targets) {
 		return nil

bones/generate_test.go

@@ -26,9 +26,9 @@ func TestGenerateGolden(t *testing.T) {
 		t.Run(name, func(t *testing.T) {
 			dir := t.TempDir()
 
-			err := Generate(getFDS(t, tc.pbFile), dir, false, nil, FormatOptions{QuoteStyle: tc.quoteStyle})
+			err := Generate(getFDS(t, tc.pbFile), dir, false, nil, Formatter{QuoteStyle: tc.quoteStyle})
 			require.NoError(t, err)
-			err = Generate(getFDS(t, tc.pbFile), dir, false, nil, FormatOptions{Lang: JS, QuoteStyle: tc.quoteStyle})
+			err = Generate(getFDS(t, tc.pbFile), dir, false, nil, Formatter{Lang: JS, QuoteStyle: tc.quoteStyle})
 			require.NoError(t, err)
 			requireSameContent(t, tc.goldenDir, dir)
 		})

bones/testdata/golden/exemplar-double/exemplar.Exemplar.Sample.js

@@ -65,6 +65,7 @@ function Sample(input) {
       //   field: "",  // string
       //   repeat: [0],  // repeated int32
       // },
+      recursive: {},  // SampleResponse (recursive)
     },
   }
 }

bones/testdata/golden/exemplar-double/exemplar.Exemplar.Sample.jsonnet

@@ -64,5 +64,6 @@ function(input) {
     //   field: "",  // string
     //   repeat: [0],  // repeated int32
     // },
+    recursive: {},  // SampleResponse (recursive)
   },
 }

bones/testdata/golden/exemplar-single/exemplar.Exemplar.Sample.js

@@ -65,6 +65,7 @@ function Sample(input) {
       //   field: '',  // string
       //   repeat: [0],  // repeated int32
       // },
+      recursive: {},  // SampleResponse (recursive)
     },
   }
 }

bones/testdata/golden/exemplar-single/exemplar.Exemplar.Sample.jsonnet

@@ -64,5 +64,6 @@ function(input) {
     //   field: '',  // string
     //   repeat: [0],  // repeated int32
     // },
+    recursive: {},  // SampleResponse (recursive)
   },
 }

go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/alecthomas/protobuf v0.0.0-20220411053735-2a9f60104b87
 	github.com/google/go-jsonnet v0.17.0
 	github.com/stretchr/testify v1.7.0
+	golang.org/x/exp v0.0.0-20220414153411-bcd21879b8fd
 	golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
 	google.golang.org/genproto v0.0.0-20220407144326-9054f6ed7bac
@@ -21,7 +22,7 @@ require (
 	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	golang.org/x/sys v0.0.0-20210510120138-977fb7262007 // indirect
+	golang.org/x/sys v0.0.0-20211019181941-9d821ace8654 // indirect
 	golang.org/x/text v0.3.5 // indirect
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b // indirect
 )

go.sum

@@ -89,6 +89,8 @@ golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACk
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
+golang.org/x/exp v0.0.0-20220414153411-bcd21879b8fd h1:zVFyTKZN/Q7mNRWSs1GOYnHM9NiFSJ54YVRsD0rNWT4=
+golang.org/x/exp v0.0.0-20220414153411-bcd21879b8fd/go.mod h1:lgLbSvA5ygNOMpwM/9anMpWVlVJ7Z+cHWq/eFuinpGE=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
 golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
@@ -121,8 +123,9 @@ golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210510120138-977fb7262007 h1:gG67DSER+11cZvqIMb8S8bt0vZtiN6xWYARwirrOSfE=
 golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20211019181941-9d821ace8654 h1:id054HUawV2/6IGm2IV8KZQjqtwAOo2CYlOToYqa0d0=
+golang.org/x/sys v0.0.0-20211019181941-9d821ace8654/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=