OCaml 5.0 support

[edwintorok]

I got this error from ocaml-lsp-server (which vendors merlin):

[ERROR][2022-12-26 22:14:37] .../vim/lsp/rpc.lua:733	"rpc"	"ocamllsp"	"stderr"	'detached: /-----------------------------------------------------------------------\n| Internal error: Uncaught exception.\n| Not_found\n| Raised at Merlin_utils__Std.Option.get in file "ocaml-lsp-server/vendor/merlin/src/utils/std.ml" (inlined), line 301, characters 14-29\n| Called from Ocaml_typing__Magic_numbers.Cmi.report_error in file "ocaml-lsp-server/vendor/merlin/src/ocaml/typing/magic_numbers.ml", line 59, characters 10-64\n| Called from Stdlib__Format.output_acc in file "format.ml", line 1360, characters 4-20\n| Called from Stdlib__Format.kasprintf.k in file "format.ml", line 1464, characters 4-22\n| Called from Ocaml_lsp_server__Diagnostics.merlin_diagnostics.(fun).make_message in file "ocaml-lsp-server/src/diagnostics.ml", line 307, characters 30-60\n| Called from Ocaml_lsp_server__Diagnostics.merlin_diagnostics.(fun) in file "ocaml-lsp-server/src/diagnostics.ml", line 309, characters 30-63\n| Called from Stdlib__List.rev_map.rmap_f in file "list.ml", line 103, characters 22-25\n| Called from Ocaml_lsp_server__Diagnostics.merlin_diagnostics.(fun) in file "ocaml-lsp-server/src/diagnostics.ml", line 298, characters 12-1023\n| Called from Merlin_utils__Std.let_ref in file "ocaml-lsp-server/vendor/merlin/src/utils/std.ml", line 686, characters 8-12\n| Re-raised at Merlin_utils__Std.let_ref in file "ocaml-lsp-server/vendor/merlin/src/utils/std.ml", line 688, characters 30-39\n| Called from Merlin_utils__Misc.try_finally in file "ocaml-lsp-server/vendor/merlin/src/utils/misc.ml", line 45, characters 8-15\n| Re-raised at Merlin_utils__Misc.try_finally in file "ocaml-lsp-server/vendor/merlin/src/utils/misc.ml", line 62, characters 10-24\n| Called from Stdlib__Fun.protect in file "fun.ml", line 33, characters 8-15\n| Re-raised at Stdlib__Fun.protect in file "fun.ml", line 38, characters 6-52\n| Called from Merlin_kernel__Mocaml.with_state in file "ocaml-lsp-server/vendor/merlin/src/kernel/mocaml.ml", line 18, characters 8-38\n| Re-raised at Merlin_kernel__Mocaml.with_state in file "ocaml-lsp-server/vendor/merlin/src/kernel/mocaml.ml", line 20, characters 42-53\n| Called from Ocaml_lsp_server__Document.Single_pipeline.use.(fun) in file "ocaml-lsp-server/src/document.ml", line 153, characters 22-77\n| Called from Stdune__Exn_with_backtrace.try_with in file "otherlibs/stdune/exn_with_backtrace.ml", line 9, characters 8-12\n| Re-raised at Stdune__Exn.raise_with_backtrace in file "otherlibs/stdune/exn.ml" (inlined), line 36, characters 27-56\n| Called from Stdune__Exn_with_backtrace.reraise in file "otherlibs/stdune/exn_with_backtrace.ml", line 18, characters 33-71\n| Called from Fiber__Core.O.(>>|).(fun) in file "src/fiber/core.ml", line 250, characters 36-41\n| Called from Fiber__Scheduler.exec in file "src/fiber/scheduler.ml", line 73, characters 8-11\n\\-----------------------------------------------------------------------\n\n'

I can't reproduce the error anymore (even if I switch between 4.14 and 5.0) but looking at the stacktrace the following should fix this:

diff --git a/src/ocaml/typing/magic_numbers.ml b/src/ocaml/typing/magic_numbers.ml
index 386f87993..ef7aade20 100644
--- a/src/ocaml/typing/magic_numbers.ml
+++ b/src/ocaml/typing/magic_numbers.ml
@@ -22,6 +22,7 @@ module Cmi = struct
     | "Caml1999I029" -> Some "4.12"
     | "Caml1999I030" -> Some "4.13"
     | "Caml1999I031" -> Some "4.14"
+    | "Caml1999I032" -> Some "5.0"
     | _ -> None
 
   open Format

However the other 'bump magic number' commits I looked at also bumped magic numbers elsewhere, should I just open a PR and bump the magic numbers like done in the other commits, or is there anything else that needs to be done for 5.0 support?

[edwintorok]

Ah I see now, the 5.0 support is on the 500 branch, not master, which has indeed bumped some of the magic numbers but not all. Opened a PR to add the missing one, and an assertion to check that merlin can recognize its own magic number it got compiled with.