On Fri, Sep 25, 2020 at 03:15:57PM +0200, Markus Armbruster wrote: > Cleber Rosa <cr...@redhat.com> writes: > > > On Wed, Sep 23, 2020 at 02:37:27PM -0400, John Snow wrote: > >> On 9/23/20 11:26 AM, Eduardo Habkost wrote: > >> > On Tue, Sep 22, 2020 at 05:00:51PM -0400, John Snow wrote: > >> > > Make the file handling here just a tiny bit more idiomatic. > >> > > (I realize this is heavily subjective.) > >> > > > >> > > Use exist_ok=True for os.makedirs and remove the exception, > >> > > use fdopen() to wrap the file descriptor in a File-like object, > >> > > and use a context manager for managing the file pointer. > >> > > > >> > > Signed-off-by: John Snow <js...@redhat.com> > >> > > >> > Reviewed-by: Eduardo Habkost <ehabk...@redhat.com> > >> > > >> > I really miss a comment below explaining why we use > >> > open(os.open(pathname, ...), ...) instead of open(pathname, ...). > > This code: > > fd = os.open(pathname, os.O_RDWR | os.O_CREAT, 0o666) > f = open(fd, 'r+', encoding='utf-8') > > >> Not known to me. It was introduced in 907b846653 as part of an effort to > >> reduce rebuild times. Maybe this avoids a modification time change if the > >> file already exists? > >> > >> Markus? > > > > AFACIT the change on 907b846653 is effective because of the "is new > > text different from old text?" conditional. I can not see how the > > separate/duplicate open/fdopen would contribute to that. > > > > But, let's hear from Markus. > > This was my best attempt to open the file read/write, creating it if it > doesn't exist. > > Plain > > f = open(pathname, "r+", encoding='utf-8') > > fails instead of creates, and > > f = open(pathname, "w+", encoding='utf-8') > > truncates. > > If you know a better way, tell me!
IIUC, you need "a+" as the mode, rather than "w+" Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
