Re: ediff failure if diff doesn't exist

[Jesper Harder]

Richard Stallman <address@hidden> writes:

>     > But that wasn't necessary before, so I suspect that
>     > call-process has changed to now signal an error.
>
>     Unless there's a really compelling reason for this change I
>     think it should be reverted.  A *lot* of code depends on the
>     assumption that `call-process' returns a non-zero value if it
>     fails.
>
> What change are you talking about?

I incorrectly thought that `call-process' had changed to signal an
error instead of returning a non-zero value when the program isn't
found.  But now I just checked it in Emacs 21 ... and it doesn't seem
to have changed. Sorry.

> Hold your horses!  You are rushing ahead to solve the problem
> using one approach, but I am not sure it is the right approach.

I wasn't really proposing a solution, just pointing to some places
that might fail to work as intended, because the code doesn't take the
possibility of signalling an error into account. Which is
understandable because you can easily misunderstand the docstring to
say that call-process won't signal an error.