bug#81508: 31.0.50; package.el archive contents download robustness issues

Philip Kaludercic [28/Jul  3:22pm GMT] wrote:
> Sean Whitton <[email protected]> writes:
>
>> If there is an ENOSPC in the middle of writing the archive-contents
>> file, the truncated file is left behind.  This is because
>> package--download-one-archive uses plain write-region instead of writing
>> into a temporary file and then atomically renaming it into place.
>
> I feel like this is not the only place where something like this could
> go wrong, so it would be useful to perhaps have some functionality
> directly in url.el to download a file and rename it atomically, since
> IIRC there are a number of edge-cases to consider here.

Makes sense.

>> Worse, if a truncated file has been left behind,
>> package--read-archive-file errors instead of trying to delete and
>> re-download the file.
>
> Assuming we fix the above, should we also make this function more robust
> by e.g. trying to re-download the archive if it is malformed?

I'm not sure myself, I don't use package.el.  In this bug, I'm more
concerned about errors being signaled during Emacs startup.

-- 
Sean Whitton