bug#11999: 24.1.50; New Info file suffix ".info" breaks `Info-find-node-2'

[Stefan Monnier]

> The doc string IMO does not tell enough, and there's no other
> documentation about user-error, neither in the ELisp manual nor in
> NEWS (which only mentions its existence).

Can you be specific about what additional info you need?

> Stefan, could you perhaps provide some insight?  What is a "pilot
> error" in this context,

A error of the user rather than of the author of the code.

> and how should Lisp programs use this new facility to (supposedly)
> provide better diagnostics and/or better error handling?

user-error is just a standard "debug-ignored-error".  So instead of
using error plus adding the text of the error to debug-ignored-errors,
you can just user user-error.

If Drew gets a user-error that drops him in the debugger, it's because
he removed` user-error' from debug-ignored-errors.

>> An index lookup that finds no hit is NOT "expected to be the result of an
>> incorrect manipulation on the part of the user, rather than the result of an
>> actual problem." 

By "actual problem", I meant "a bug in the code", i.e. a problem that
can be fixed by correcting the code.


        Stefan