protobuf: fix casing of json attributes with the switch from gogo

With the switch from gogo, the `oneof` fields no longer have their
`json:"name"` fields emitted. Protobuf doesn't formally support these
fields and tells users to use the `protojson` package, but we didn't and
the official format is incompatible with the current format we use.

This adds some custom marshaling code to the already existant custom
unmarshaling code to ensure these fields are marshaled with the correct
casing.

Signed-off-by: Jonathan A. Sternberg <[email protected]>

Author: jsternberg

solver/pb/json.go

@@ -2,58 +2,100 @@ package pb
 
 import "encoding/json"
 
-func (m *Op) UnmarshalJSON(data []byte) error {
-	var v struct {
-		Inputs []*Input `json:"inputs,omitempty"`
-		Op     struct {
-			*Op_Exec
-			*Op_Source
-			*Op_File
-			*Op_Build
-			*Op_Merge
-			*Op_Diff
-		}
-		Platform    *Platform          `json:"platform,omitempty"`
-		Constraints *WorkerConstraints `json:"constraints,omitempty"`
+type jsonOp struct {
+	Inputs []*Input `json:"inputs,omitempty"`
+	Op     struct {
+		Exec   *ExecOp   `json:"exec,omitempty"`
+		Source *SourceOp `json:"source,omitempty"`
+		File   *FileOp   `json:"file,omitempty"`
+		Build  *BuildOp  `json:"build,omitempty"`
+		Merge  *MergeOp  `json:"merge,omitempty"`
+		Diff   *DiffOp   `json:"diff,omitempty"`
 	}
+	Platform    *Platform          `json:"platform,omitempty"`
+	Constraints *WorkerConstraints `json:"constraints,omitempty"`
+}
+
+func (m *Op) MarshalJSON() ([]byte, error) {
+	var v jsonOp
+	v.Inputs = m.Inputs
+	switch op := m.Op.(type) {
+	case *Op_Exec:
+		v.Op.Exec = op.Exec
+	case *Op_Source:
+		v.Op.Source = op.Source
+	case *Op_File:
+		v.Op.File = op.File
+	case *Op_Build:
+		v.Op.Build = op.Build
+	case *Op_Merge:
+		v.Op.Merge = op.Merge
+	case *Op_Diff:
+		v.Op.Diff = op.Diff
+	}
+	v.Platform = m.Platform
+	v.Constraints = m.Constraints
+	return json.Marshal(v)
+}
 
+func (m *Op) UnmarshalJSON(data []byte) error {
+	var v jsonOp
 	if err := json.Unmarshal(data, &v); err != nil {
 		return err
 	}
 
 	m.Inputs = v.Inputs
 	switch {
-	case v.Op.Op_Exec != nil:
-		m.Op = v.Op.Op_Exec
-	case v.Op.Op_Source != nil:
-		m.Op = v.Op.Op_Source
-	case v.Op.Op_File != nil:
-		m.Op = v.Op.Op_File
-	case v.Op.Op_Build != nil:
-		m.Op = v.Op.Op_Build
-	case v.Op.Op_Merge != nil:
-		m.Op = v.Op.Op_Merge
-	case v.Op.Op_Diff != nil:
-		m.Op = v.Op.Op_Diff
+	case v.Op.Exec != nil:
+		m.Op = &Op_Exec{v.Op.Exec}
+	case v.Op.Source != nil:
+		m.Op = &Op_Source{v.Op.Source}
+	case v.Op.File != nil:
+		m.Op = &Op_File{v.Op.File}
+	case v.Op.Build != nil:
+		m.Op = &Op_Build{v.Op.Build}
+	case v.Op.Merge != nil:
+		m.Op = &Op_Merge{v.Op.Merge}
+	case v.Op.Diff != nil:
+		m.Op = &Op_Diff{v.Op.Diff}
 	}
 	m.Platform = v.Platform
 	m.Constraints = v.Constraints
 	return nil
 }
 
-func (m *FileAction) UnmarshalJSON(data []byte) error {
-	var v struct {
-		Input          InputIndex  `json:"input"`
-		SecondaryInput InputIndex  `json:"secondaryInput"`
-		Output         OutputIndex `json:"output"`
-		Action         struct {
-			*FileAction_Copy
-			*FileAction_Mkfile
-			*FileAction_Mkdir
-			*FileAction_Rm
-		}
+type jsonFileAction struct {
+	Input          InputIndex  `json:"input"`
+	SecondaryInput InputIndex  `json:"secondaryInput"`
+	Output         OutputIndex `json:"output"`
+	Action         struct {
+		Copy   *FileActionCopy   `json:"copy,omitempty"`
+		Mkfile *FileActionMkFile `json:"mkfile,omitempty"`
+		Mkdir  *FileActionMkDir  `json:"mkdir,omitempty"`
+		Rm     *FileActionRm     `json:"rm,omitempty"`
+	}
+}
+
+func (m *FileAction) MarshalJSON() ([]byte, error) {
+	var v jsonFileAction
+	v.Input = InputIndex(m.Input)
+	v.SecondaryInput = InputIndex(m.SecondaryInput)
+	v.Output = OutputIndex(m.Output)
+	switch action := m.Action.(type) {
+	case *FileAction_Copy:
+		v.Action.Copy = action.Copy
+	case *FileAction_Mkfile:
+		v.Action.Mkfile = action.Mkfile
+	case *FileAction_Mkdir:
+		v.Action.Mkdir = action.Mkdir
+	case *FileAction_Rm:
+		v.Action.Rm = action.Rm
 	}
+	return json.Marshal(v)
+}
 
+func (m *FileAction) UnmarshalJSON(data []byte) error {
+	var v jsonFileAction
 	if err := json.Unmarshal(data, &v); err != nil {
 		return err
 	}
@@ -62,35 +104,47 @@ func (m *FileAction) UnmarshalJSON(data []byte) error {
 	m.SecondaryInput = int64(v.SecondaryInput)
 	m.Output = int64(v.Output)
 	switch {
-	case v.Action.FileAction_Copy != nil:
-		m.Action = v.Action.FileAction_Copy
-	case v.Action.FileAction_Mkfile != nil:
-		m.Action = v.Action.FileAction_Mkfile
-	case v.Action.FileAction_Mkdir != nil:
-		m.Action = v.Action.FileAction_Mkdir
-	case v.Action.FileAction_Rm != nil:
-		m.Action = v.Action.FileAction_Rm
+	case v.Action.Copy != nil:
+		m.Action = &FileAction_Copy{v.Action.Copy}
+	case v.Action.Mkfile != nil:
+		m.Action = &FileAction_Mkfile{v.Action.Mkfile}
+	case v.Action.Mkdir != nil:
+		m.Action = &FileAction_Mkdir{v.Action.Mkdir}
+	case v.Action.Rm != nil:
+		m.Action = &FileAction_Rm{v.Action.Rm}
 	}
 	return nil
 }
 
-func (m *UserOpt) UnmarshalJSON(data []byte) error {
-	var v struct {
-		User struct {
-			*UserOpt_ByName
-			*UserOpt_ByID
-		}
+type jsonUserOpt struct {
+	User struct {
+		ByName *NamedUserOpt `json:"byName,omitempty"`
+		ByID   uint32        `json:"byId,omitempty"`
 	}
+}
 
+func (m *UserOpt) MarshalJSON() ([]byte, error) {
+	var v jsonUserOpt
+	switch userOpt := m.User.(type) {
+	case *UserOpt_ByName:
+		v.User.ByName = userOpt.ByName
+	case *UserOpt_ByID:
+		v.User.ByID = userOpt.ByID
+	}
+	return json.Marshal(v)
+}
+
+func (m *UserOpt) UnmarshalJSON(data []byte) error {
+	var v jsonUserOpt
 	if err := json.Unmarshal(data, &v); err != nil {
 		return err
 	}
 
 	switch {
-	case v.User.UserOpt_ByName != nil:
-		m.User = v.User.UserOpt_ByName
-	case v.User.UserOpt_ByID != nil:
-		m.User = v.User.UserOpt_ByID
+	case v.User.ByName != nil:
+		m.User = &UserOpt_ByName{v.User.ByName}
+	default:
+		m.User = &UserOpt_ByID{v.User.ByID}
 	}
 	return nil
 }