Deprecate JSX 3 (#7042)

* deprecate jsx 3 from bsb

* clean up

* changelog

* fix changelog

CHANGELOG.md

@@ -10,6 +10,10 @@
 > - :house: [Internal]
 > - :nail_care: [Polish]
 
+# 11.1.5 (Unreleased)
+
+- Deprecate JSX 3 https://github.com/rescript-lang/rescript-compiler/pull/7042
+
 # 11.1.4
 
 - Fix issue where long layout break added a trailing comma in partial application `...`. https://github.com/rescript-lang/rescript-compiler/pull/6949

jscomp/bsb/bsb_jsx.ml

@@ -43,7 +43,13 @@ let from_map map =
            match m.?(Bsb_build_schemas.jsx_version) with
            | Some (Flo { loc; flo }) -> (
                match flo with
-               | "3" -> version := Some Jsx_v3
+               | "3" ->
+                  let loc_end =
+                    {loc with Lexing.pos_cnum = loc.Lexing.pos_cnum + 1}
+                  in
+                  let loc = {Warnings.loc_start = loc; loc_end; loc_ghost = false} in
+                  Location.deprecated loc "jsx 3 is deprecated, use jsx 4 instead";
+                  version := Some Jsx_v3
                | "4" -> version := Some Jsx_v4
                | _ -> Bsb_exception.errorf ~loc "Unsupported jsx version %s" flo
                )