Re: debugging post command hook max-lisp-eval-depth

[Stefan Monnier <monnier@IRO.UMontreal.CA>]

>> Hmm... post-command-hook is run via `safe_run_hooks` which is supposed
>> to try and catch errors such that when an error is caught the
>> corresponding function is removed from post-command-hook.
> I don't think there is a specific hook that is recursing infinitely. The
> two I noticed in the error message were both global minor modes
> (magit-file-mode & display-line-numbers).

Hmm... I don't understand what you mean: when you say "I don't think
there is a specific hook that is recursing infinitely" do you mean hook
as in "post-command-hook" or in "one of the functions placed on
post-command-hook"?

Then you say "the two ... were global minor modes", but I fail to see
how a "hook" can be a "minor mode".

>> Of course, this is a just a mitigating factor, but it should prevent the
>> problem you describe, except in those cases where the offending function
>> is constantly re-added (e.g. by a pre-command-hook).
> I think that's the case, `define-globalized-minor-mode' will add the
> post-command-hook in MODE-cmhh.

Now that I think about it, the message you get should say which hook
function had an error, since the message is emitted with:

  AUTO_STRING (format, "Error in %s (%S): %S");
  Lisp_Object hook = args[0];
  Lisp_Object fun = args[1];
  CALLN (Fmessage, format, hook, fun, error);

where `fun` is the function during which the error was signaled.

So if you only get "Lisp nesting exceeds...", check your *Messages* and
if even there you don't have the "Error in ... (...): ..." message, it
means that the error was most likely signaled elsewhere than in
post-command-hook.


        Stefan