FSET transforms field names to lowercase

[unendingblue]

Describe the bug
The command FSET transforms any given field name to lowercase.
SETing a key with fields that have mixed or uppercase names works correctly.

To Reproduce
Set an arbitrary key with an uppercase field
SET user 1 FIELD TEST 123 POINT 90 90

Get the key
GET user 1 WITHFIELDS

Response
{"ok":true,"object":{"type":"Point","coordinates":[90,90]},"fields":{"TEST":123},"elapsed":"19.744µs"}

Set the field to a new value
FSET user 1 TEST 987

Get the key again
GET user 1 WITHFIELDS

Response
{"ok":true,"object":{"type":"Point","coordinates":[90,90]},"fields":{"TEST":123,"test":987},"elapsed":"16.374µs"}

Observe that we now have a new field named "test", instead of the original "TEST" field being updated.

Expected behavior
FSET should retain the field name's letter casing.

Additional context
I don't have experience in Go, but my initial assumption is that the culprit logic is likely this:

tile38/internal/server/crud.go

Lines 843 to 860 in 51e6862

	for i := 3; i < len(args); i++ {
	arg := strings.ToLower(args[i])
	switch arg {
	case "xx":
	xx = true
	default:
	fkey := arg
	i++
	if i == len(args) {
	return retwerr(errInvalidNumberOfArguments)
	}
	if isReservedFieldName(fkey) {
	return retwerr(errInvalidArgument(fkey))
	}
	fval := args[i]
	fields = append(fields, field.Make(fkey, fval))
	}
	}

Instead of calling ToLower on 844, it should be called directly on the switched value at 845, similar to how SET works.

[iwpnd]

Good catch. Can confirm. 👍

[unendingblue]

Thanks for looking into this @iwpnd. After looking around a bit more, I am now certain that this issue has deeper roots than I originally anticipated.

Apart from FSET, this issue is also present in NEARBY's WHEREIN. I assume the reason is this function's use of ToLower:

tile38/internal/server/search.go

Line 174 in 51e6862

func (s *Server) cmdSearchArgs(

To reproduce:
SET user 1 FIELD TEST 123 POINT 90 90
NEARBY user POINT 90 90 -> Observe the key is found
NEARBY user WHEREIN TEST 1 123 POINT 90 90 -> Observe the key is not found

SET user 2 FIELD test 123 POINT 90 90
NEARBY user WHEREIN TEST 1 123 POINT 90 90 -> Observe the key is found, even though the search term is uppercase while the key's field name is lowercase

The WHERE search option does work correctly. To confirm:
NEARBY user WHERE TEST 123 123 POINT 90 90 -> Observe the correct key (user 1) is found
NEARBY user WHERE test 123 123 POINT 90 90 -> Observe the correct key (user 2) is found

This is related to issue #704. The fixes for both FSET and WHEREIN may be a breaking change for systems that have not noticed this bug, though I still do believe ironing it out is the way to go as the current behavior is inconsistent.

[iwpnd]

Can also confirm. Let's see whats going on with wherein 👀

update:
yes, whereins are appended with strings.ToLower(name) too, here.

Can I address this @tidwall? It doesn't appear to be intended, considering you can set a field in just about any case. Also this would align the behaviour of WHEREIN and WHERE.

[tidwall]

@iwpnd yes please take a look. I don’t recall this being the intended behavior.

[iwpnd]

#742 and #743 should resolve this now @tidwall

[tidwall]

Ok, I'll review asap.

[tidwall]

Fixed and merged!
@unendingblue Thanks for reporting!
@iwpnd Thanks for fixing!