Revert too-picky file-access tests

Problem reported by Andreas Schwab (Bug#37475).
* doc/lispref/files.texi (Writing to Files)
(Testing Accessibility, Kinds of Files):
Document that accessibility and file-type predicates return nil
if there is trouble determining accessibility or type.
* etc/NEWS: Adjust, and list the affected primitives.
* src/callproc.c (init_callproc): Go back to Ffile_exists_p.
* src/fileio.c (PICKY_EACCES, file_test_errno):
Remove.  All uses removed.
(Ffile_name_case_insensitive_p, Ffile_exists_p, Ffile_symlink_p)
(Ffile_directory_p, Ffile_regular_p): Document that these
functions return nil if there is trouble.
(Ffile_name_case_insensitive_p, check_file_access)
(Ffile_writable_p, Ffile_symlink_p, Ffile_directory_p)
(Ffile_accessible_directory_p, Ffile_regular_p)
* src/lread.c (Fload):
Go back to treating trouble in determining the answer as if the
file were missing.
* src/fileio.c (Ffile_newer_than_file_p): Use file_attribute_errno
not file_test_errno, since returning nil is not appropriate when
there are two files to test; e.g., in the rare cases where both
file timestamps have overflowed then neither t nor nil is correct.

1 files changed, 8 insertions, 5 deletions

diff --git a/etc/NEWS b/etc/NEWS
index cb04da189e5..6a4a6e60d4d 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2029,11 +2029,14 @@ longer defaults to 'buffer-file-name'.
 ** File metadata primitives now signal an error if I/O, access, or
 other serious errors prevent them from determining the result.
 Formerly, these functions often (though not always) returned nil.
-For example, if searching /etc/firewalld results in an I/O error,
-(file-symlink-p "/etc/firewalld/firewalld.conf") now signals an error
-instead of returning nil, because file-symlink-p cannot determine
-whether a symbolic link exists there.  These functions still behave as
-before if the only problem is that the file does not exist.
+For example, if there is an access error, I/O error or low-level
+integer overflow when getting the attributes of a file F,
+(file-attributes F) now signals an error instead of returning nil.
+These functions still behave as before if the only problem is that the
+file does not exist.  The affected primitives are
+directory-files-and-attributes, file-acl, file-attributes, file-modes,
+file-newer-than-file-p, file-selinux-context, file-system-info, and
+set-visited-file-modtime.
 
 ---
 ** The function 'eldoc-message' now accepts a single argument.