Regression since dace191 (fix fromjson to keep integer precision (close #172))

[wader]

$ git co dace191026f576cb7d8ffbea0c29e8c13097a7c1
$ go run cmd/gojq/main.go -n '"123abc" | fromjson'
123

$ git co dace191026f576cb7d8ffbea0c29e8c13097a7c1~1
$ go run cmd/gojq/main.go -n '"123abc" | fromjson'
gojq: invalid character 'a' after top-level value
exit status 5

Same for "{}asd" and "[]abc". I think we're hitting the support for decoding a stream of JSON values.

As I guess we still need to use UseNumber() maybe a possible solutions could be something like this:

func funcFromJSON(v interface{}) interface{} {
	switch v := v.(type) {
	case string:
		var w interface{}
		dec := json.NewDecoder(strings.NewReader(v))
		dec.UseNumber()
		err := dec.Decode(&w)
		if err != nil {
			return err
		}
		var n interface{}
		err = dec.Decode(&n)
		if err != io.EOF {
			// would be nice with better error, the decode err might be confusing to show?
                        // for "123abc" err is "invalid character 'a' looking for beginning of value"
			return fmt.Errorf("invalid character after top-level value")
		}
		return normalizeNumbers(w)
	default:
		return &funcTypeError{"fromjson", v}
	}
}

Work fine with "123 \n" etc also.

[itchyny]

What's the actual problem here? I don't think this is a regression.

[itchyny]

Hmm, I'll reconsider later. Maybe checking Token() is enough.

[wader]

What's the actual problem here? I don't think this is a regression.

That is used to throw error on unexpected trailing data, same as jq does:

$ jq -n '"{} 123" | fromjson'
jq: error (at <unknown>): Unexpected extra JSON values (while parsing '{} 123')
$ jq -n '"123 abc" | fromjson'
jq: error (at <unknown>): Invalid numeric literal at EOF at line 1, column 7 (while parsing '123 abc')

Hmm, I'll reconsider later. Maybe checking Token() is enough.

👍 yes that might be better. The double call to Decode and check for EOF feel a bit ugly.

[wader]

Thanks!