Appreciation

[grayswandyr]

Hi,
my colleagues and myself are currently developing a research prototype and we have started using ppx_minidebug, a little bit in v2 and even more in v3. Thanks for the good work! For years, we have mainly relied upon debug-printing statements. Ppx_minidebug saves us a lot of time since deciding to print some logging data is so easy, in particular with debug_sexp.

We were able to find some bugs quite quickly this way and we almost don't use debug-printing anymore. We still have one use of debug printing, namely printing messages our tool sends to external tools, as it still seems a bit easier to get a complete trace of sent messages (using [%log] here is still nice and we can almost get the same result with minidebug_view show and grep). For instance, we can debug-print a trace such as:

$ ./tool.exe -vv
[D] msg1
[D] msg2
...

With ppx_minidebug, we rather do:

% minidebug_view tool-log.db show | grep -A1 write
[debug] write @ lib/foo.ml:55:23-62:18
    "msg1"
[debug] write @ lib/foo.ml:55:23-62:18
    "msg2"
...

The former printing is a bit more readable and asks for less shell wizardry (if we need to do more sophisticated greps/seds), which is useful in this specific use case. But not a big deal.

Another issue we had was with functions returning an option. They didn't print anything if they returned None, due to the default option sexp-printer. This was surprising at first. (Btw, sexplib0 doesn't contain sexp-converters for some types in the OCaml 5.3 stdlib, which is not related to ppx_minidebug per se but has an impact on its use)

We also don't understand everything in the way minidebug_view shows a trace. It sometimes seems the nesting is not right. Also, it's a bit too verbose with '[debug]' and '[value]' strings everywhere and times that are shown by default. We tried to change the configuration of the reporter but we may have misunderstood the documentation because times are still shown in spite of our efforts. Not sure of the effect of scope ids options either. This is what we use:

let _get_local_debug_runtime =
  let logname = "tool-log.db" in
  let time_tagged = Minidebug_runtime.Not_tagged in
  let location_format = Minidebug_runtime.File_only in
  let elapsed_times = Minidebug_runtime.Not_reported in
  let print_scope_ids = true in
  let verbose_scope_ids = true in
  let runtime =
    Minidebug_db.debug_db_file ~time_tagged ~elapsed_times ~location_format
      ~print_scope_ids ~verbose_scope_ids logname
  in
  fun () -> runtime

Also, we often recompile our tool and a change-detection mechanism would be nice in minidebug_view, to propose a refresh of what's displayed.

Finally, we have a recurring bug seemingly related to Notty:

Error: Invalid_argument("Notty: control char: U+0A, \"          ...

All in all, we don't have big issues and minidebug really helps us a lot, so keep up the good work!

[lukstafi]

Please use the latest head, opam update is very long overdue. Hopefully soon!