Bind() panics when the destination is a map with non-interface types #2552
Description
Issue Description
When calling context Bind(...) with a map which has non interface or non assignable value type, a panic is triggered. Even though this is a rare case, and can be worked around using a different map type, or using BindBody, we should not have panics in echo. This looks like it has been the behavior since 2019 or so based on git blame.
This comes down to the reflect assignment here:
Line 137 in 584cb85
func (b *DefaultBinder) bindData(destination interface{}, data map[string][]string, tag string) error {
...
// Map
if typ.Kind() == reflect.Map {
for k, v := range data {
val.SetMapIndex(reflect.ValueOf(k), reflect.ValueOf(v[0]))
}
return nil
}
...
I couldn't find an issue for this elsewhere.
Expected behaviour
Assignable values are bound. Unassignable values are ignored.
Actual behaviour
It panics!
For example:
panic: reflect.Value.SetMapIndex: value of type string is not assignable to type int
Steps to reproduce
See the code below. Call Bind() with a map[string]int and some string query or path parameter available in the context.
Working code to debug
package main
import (
"github.com/labstack/echo/v4"
"net/http"
)
type TestBodyMapInt map[string]int
func main() {
e := echo.New()
// test: curl -XPOST --header "Content-Type: application/json" -d '{"module1": 2, "module2": 3}' http://127.0.0.1:8080/test/1
e.POST("/test/:id", func(c echo.Context) error {
p := TestBodyMapInt{}
if err := c.Bind(&p); err != nil {
return err
}
return c.JSON(http.StatusOK, p)
})
e.Start("127.0.0.1:8080")
}Version/commit
github.com/labstack/echo/v4 v4.11.3