Re: Improve reporting of I/O, access errors for Emacs

[Paul Eggert]

On 9/12/19 11:04 AM, Eli Zaretskii wrote:
> We should instead have such logic on higher levels, where the
> semantics and the meaning of errors are clear.

If lower levels suppress the info, logic on higher levels cannot obtain 
the information and therefore cannot deal with the errors. So there must 
be some change to the lower levels, regardless of what changes might be 
advisable at higher levels.

> if Emacs just needs
> to return some information about a file, and the file turns out to be
> inaccessible, why do we need to signal an error

The same reason insert-file-contents signals an error when a file is 
inaccessible: the requested information is not available, and this is an 
exceptional condition.

I should mention that I've been trying out the new code and it works 
fine for me. All tests pass. The exceptional conditions in question are 
rare in practice; I found them only because I was trying out some stress 
tests that didn't work right.