This fixes a bug I recently introduced.
* src/diff.c (compare_files): Set and use openerr to avoid
the need for a doomed second attempt at openat.
Don’t insist on openat succeeding before trying fstatat.
Unless openat fails with ENOENT, ENOTDIR, ELOOP, EOVERFLOW, ENAMETOOLONG
it’s possible for it to fail even when fstatat would succeed.
ENOTDIR also means the file does not exist.
However, do not worry about EBADF as that is no longer possible
now that diff uses xstdopen. When checking whether a file should
be considered to be nonexistent, do not require the other file
desc to be UNOPENED or STDIN_FILENO; all that is needed is
for the other file to not have an ENOENT or ENOTDIR failure.
* src/diff.h (struct file_data): New member openerr.
(OPEN_FAILED): New constant.
* tests/new-file: Add a regression test to catch the bug
fixed by the above.
diff: fix recent -N regression
* src/diff.c (compare_files): Fix recent regression, by
looking at cmp.file[1 - f].err rather than cmp.file[1 - f].desc.
Also, do not bother checking for EBADF, as that’s no longer
possible now that diff uses xstdopen.
* NEWS: Mention this.
* bootstrap.conf (gnulib_modules): Add stdopen.
* doc/diffutils.texi (Comparing Directories):
Do not document behavior if stdin is closed.
* src/diff.c: Include stdopen.h.
(main): Call stdopen early.
(compare_files) [__hpux]: Remove recently-introduced
special case for HP-UX exec with stdin closed.
* tests/new-file: Remove tests of the removed feature.
* NEWS: Document this.
* doc/diffutils.texi (Comparing Directories): Likewise.
Also, document that these options work at the top level.
* src/diff.c (compare_files): Treat EBADF like ENOENT, to handle
the case where "-" is closed. Allow the other file to be
STDIN_FILENO, in case it's "-".
* tests/Makefile.am (TESTS): Add new-file.
* tests/new-file: New file.
