bug#37475: 27.0.50 bootstrap fails

[Sven Joachim <svenjoac@gmx.de>]

On 2019-09-21 12:37 +0300, Eli Zaretskii wrote:

>> Date: Sat, 21 Sep 2019 12:33:32 +0300
>> From: Eli Zaretskii <eliz@gnu.org>
>> Cc: 37475@debbugs.gnu.org
>>
>>   (defcustom message-user-organization-file
>>     (let (orgfile)
>>       (dolist (f (list "/etc/organization"
>> 		       "/etc/news/organization"
>> 		       "/usr/lib/news/organization"))
>> 	(when (file-readable-p f)
>> 	  (setq orgfile f)))
>>       orgfile)
>>     "Local news organization file."
>>
>> file-readable-p is documented to "Return t if file FILENAME exists and
>> you can read it."  So I think Ffile_readable_p should not signal an
>> error if the file does not exist, it should return nil instead.
>
> Hmm... I see that it does already.
>
> Andreas, can you tell whether this file exists on your system, and
> what was the errno value inside Ffile_readable_p?

It's EACCES aka Permission denied, given in the original bug report.  To
reproduce it:

,----
| $ sudo mkdir -p /etc/news
| $ sudo chmod 700 /etc/news
| $ rm -f lisp/gnus/deuglify.el
| $ make
`----

That's due to commit 9dc306b1db08 ("Improve reporting of I/O, access
errors") which seems over-zealous here: if there are insufficient
permissions to access the parent directory, file-readable-p ought to
return nil, I think.

Cheers,
       Sven