Re: [PATCH 10/10] Don't iterate over all buffers in set_default_internal

[Stefan Monnier]

> More complex is the change to set_internal.
> Previously, if we were in the following scenario, which we'll refer to
> as scenario A:
> - We are in the scope of a let_default binding for some variable,
> - the current buffer is the buffer which created that let binding,
> - and we call setq for that variable.
> The variable would not become buffer-local after the setq, because of
> this check in set_internal.  But, nevertheless, the value we'd see for
> the variable would still appear different in the current buffer from
> other buffers. See the first, minor bug mentioned in bug#44733.

See my comment there.
The bug is real, but I think your patch "fixes" in an incorrect way.

> The old behavior of let_default is that if we setq in a buffer other
> than the one which created the let_default binding, our binding
> wouldn't be unwound after the let_default was done.  But if we setq in
> the buffer that created the let_default binding (that is, in scenario
> A) then that binding would be unwound.

If you can add tests for these subtleties at the same time as (or
before) these patches, that would be very helpful.


        Stefan