Error in v1.10.1: interface {} is func(interface {}) float64, not func(string) float64

[zachaller]

We use this in argo-rollouts code base and when we dependabot upgraded use to 1.10 we now have our unit tests failing with this error

interface conversion: interface {} is func(interface {}) float64, not func(string) float64

I have done a little bit of digging and it seems like this file got added which defines a set of functions. This seems to break our env which we have defined here I think because it is missing the type of functions we have passed in such as asFloat

[antonmedv]

I see. Will try to fix this bug.

[zachaller]

@antonmedv awesome glad it is a bug, and thank you for the great library :D

[antonmedv]

@zachaller will try to fix it over the weekend.

[antonmedv]

I need little bit more info, as this code works as expected:

• https://go.dev/play/p/ndMzR1MNFNA

package main

import (
	"fmt"
	"reflect"
	"strconv"

	"github.com/antonmedv/expr"
)

func main() {
	env := map[string]interface{}{
		"int8":    int8(1),
		"asFloat": asFloat,
	}
	code := `asFloat(int8)`

	program, err := expr.Compile(code, expr.Env(env))
	if err != nil {
		panic(err)
	}

	output, err := expr.Run(program, env)
	if err != nil {
		panic(err)
	}

	fmt.Printf("%T(%v)", output, output)
}

func asFloat(in interface{}) float64 {
	switch i := in.(type) {
	case float64:
		return i
	case float32:
		return float64(i)
	case int64:
		return float64(i)
	case int32:
		return float64(i)
	case int16:
		return float64(i)
	case int8:
		return float64(i)
	case int:
		return float64(i)
	case uint64:
		return float64(i)
	case uint32:
		return float64(i)
	case uint16:
		return float64(i)
	case uint8:
		return float64(i)
	case uint:
		return float64(i)
	case string:
		inAsFloat, err := strconv.ParseFloat(i, 64)
		if err == nil {
			return inAsFloat
		}
		panic(err)
	}
	panic(fmt.Sprintf("asFloat() not supported on %v %v", reflect.TypeOf(in), in))
}

Can you create an example with error? Thanks.

[xio812]

The error occurs when converting a string to float using asFloat: https://go.dev/play/p/6BG_QVOfdz6

[antonmedv]

Ok, thanks. This is a regression test:

func TestFastCall(t *testing.T) {
	env := map[string]interface{}{
		"func": func(in interface{}) float64 {
			return 8
		},
	}
	code := `func("8")`

	program, err := expr.Compile(code, expr.Env(env))
	assert.NoError(t, err)

	out, err := expr.Run(program, env)
	assert.NoError(t, err)
	assert.Equal(t, float64(8), out)
}

[antonmedv]

Fixed in 9009d4d Will release a new version.

[antonmedv]

https://github.com/antonmedv/expr/releases/tag/v1.10.1

[zachaller]

Awesome thank you for the super quick turnaround!

[vincentbernat]

I have another one:

interface conversion: interface {} is core.classifyStringFunc, not func(string) bool (1:1)

However, I have:

type classifyStringFunc func(string) bool

I can work around the issue with

type classifyStringFunc = func(string) bool

Maybe do you prefer another issue?

[antonmedv]

Maybe do you prefer another issue?

Yes, please.