Fix: Double-quoted types when encoded to JSON

[rafaeljusto]

Description

When encoding map keys to JSON, it will give priority to the encoding.TextMarshaler implementation, automatically adding quotes to the encoded value. If the encoding already adds the quote,s it will end up with a double-quoted JSON property that may cause issues in the decoding phase.

From https://pkg.go.dev/encoding/json#Marshal:

The map's key type must either be a string, an integer type, or implement encoding.TextMarshaler.

• keys of any string type are used directly
• keys that implement encoding.TextMarshaler are marshaled
• integer keys are converted to strings

Example:

package main

import (
	"encoding/json"
	"fmt"
	"strconv"
)

func main() {
	example1 := map[TypeA]struct{}{
		TypeA(1): struct{}{},
	}
	encoded, err := json.Marshal(example1)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println(string(encoded))

	example2 := map[TypeB]struct{}{
		TypeB(2): struct{}{},
	}
	encoded, err = json.Marshal(example2)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println(string(encoded))

	example3 := map[TypeC]struct{}{
		TypeC(3): struct{}{},
	}
	encoded, err = json.Marshal(example3)
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println(string(encoded))
}

type TypeA int

func (t TypeA) MarshalJSON() ([]byte, error) {
	return []byte(`"` + strconv.FormatInt(int64(t), 10) + `"`), nil
}

func (t TypeA) MarshalText() ([]byte, error) {
	return t.MarshalJSON()
}

type TypeB int

func (t TypeB) MarshalJSON() ([]byte, error) {
	return []byte(`"` + strconv.FormatInt(int64(t), 10) + `"`), nil
}

type TypeC int

func (t TypeC) MarshalText() ([]byte, error) {
	return []byte(strconv.FormatInt(int64(t), 10)), nil
}

Output:

{"\"1\"":{}}
{"2":{}}
{"3":{}}

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Testing

• Tests pass locally (go test -v ./...)
• Added/updated tests for new functionality

Checklist

• Code follows project style guidelines
• Self-reviewed the code
• Added necessary documentation
• No new warnings or errors