Re: use of `user-error'

[Michael Heerdegen]

Hi,

I really would like to discuss these questions raised by Drew (see
at the bottom, shortened!).

I would love to have `debug-on-error' bound to t all the time, to get an
immediate backtrace of errors that happen very rarely and are hard to
reproduce.  But getting a popped up debugger every time I hit a wrong
key or did something obviously wrong by accident is a pain in the ass.

So, can we try to substitute the appropriate occurrences of `error' by
`user-error', or are there any things that prevent us from doing that?


Thanks,

Michael.

> 1. I see many places in the trunk source code where `error' is used
> instead of `user-error' and where I would naively expect the latter to
> be used.
>
> Is this because most occurrences of `error' have simply not yet been
> updated to `user-error', or am I misunderstanding what `user-error' is
> for? [...]

> 2. When `user-error' is used, a user will not get a backtrace, even
> with non-nil `debug-on-error'.
>
> For a developer to request that a user obtain a backtrace in such a
> case, it seems that s?he must now ask the user to also customize
> debug-ignored-errors' to remove `user-error' from the value, in
> addition to turning on `debug-on-error'.
>
> That is a bit of bother to explain and do.  Is there a simpler
> approach? [...]

> 3. 3rd-party developers often look to the Emacs source code as a
> guideline for new things like this. [...]