`Default` overwrites existing value
JeanMertz opened this issue · comments
Jean Mertz commented
The transformer name default
to me implies that the key is set to the value only if no value is already set. Instead, as far as I can tell, right now it simply means "always set this value, no matter what".
I'm writing my own transformer to override this behaviour, but I figured I'd report this issue, in case you agree with me that the current behaviour is unexpected, based on the name.
Jean Mertz commented
FYI, here's the transformer I wrote, in case this is helpful to someone (this depends on #72):
func transformSetIfMissing(spec *transform.Config, data []byte) ([]byte, error) {
for k, v := range *spec.Spec {
var err error
// If no error is returned, it means the path was found, and we return the
// existing value.
if _, err = transform.GetJSONRaw(data, k, true); err == nil {
return data, nil
}
// If any error other than `NonExistentPath` is returned, something went
// wrong and we return the error.
if err != nil && err != transform.NonExistentPath {
return nil, err
}
b, err := json.Marshal(v)
if err != nil {
return nil, transform.ParseError(fmt.Sprintf("Warn: Unable to coerce element to json string: %v", v))
}
data, err = transform.SetJSONRaw(data, b, k)
if err != nil {
return nil, err
}
}
return data, nil
}
and the tests:
func TestTransformSetIfMissing(t *testing.T) {
t.Parallel()
tests := map[string]struct {
spec map[string]interface{}
in string
out string
}{
"set default": {
map[string]interface{}{"hello": "world"},
`{ "hi": "universe" }`,
`{ "hi": "universe", "hello": "world" }`,
},
"ignore if exists": {
map[string]interface{}{"hi": "world"},
`{ "hi": "universe" }`,
`{ "hi": "universe" }`,
},
"set nested default": {
map[string]interface{}{"hi.world": false},
`{ "hi": { "universe": true } }`,
`{ "hi": { "universe": true, "world": false } }`,
},
"complex structure": {
map[string]interface{}{"hi": map[string]interface{}{"my": "world"}},
`{ "hello": "universe" }`,
`{ "hello": "universe", "hi": { "my": "world" } }`,
},
}
for name, tt := range tests {
t.Run(name, func(t *testing.T) {
cfg := &transform.Config{Spec: &tt.spec}
b, err := transformSetIfMissing(cfg, []byte(tt.in))
require.NoError(t, err)
assert.JSONEq(t, tt.out, string(b))
})
}
}
Ryan Leary commented
Thanks for the report!
Tom commented
Closing as this is the documented behavior of the default
transformer