On 16/12/2023 21:46, Bernhard Voelker wrote:
On 12/15/23 21:13, Michael Stone wrote:
On Fri, Dec 15, 2023 at 11:21:06AM -0800, Paul Eggert wrote:
Stlll, Pádraig gave a reasonable summary of why the change was made,
To clarify my summary a little, there I said that -n now _immediately_ fails.
I should have said _silently_ fails. I.e. the complete copy operation
proceeds as before, and only the exit status is at issue here.
despite its incompatibility with previous behavior. (One thing I'd add
is that the FreeBSD behavior is inherently less race-prone.)
Whether the implementation is race-prone or not is an internal thing.
I think we're currently discussing more on a user-perspective level.
IIUC then the question is whether `cp -n` should continue to behave like
the (new) `cp --update=none` which returns EXIT_SUCCESS.
Regardless what other implementations do, when reading the -n description
from a user's point of view:
-n, --no-clobber do not overwrite an existing file (overrides a
-u or previous -i option). See also --update
then I'd expect the tool to just skip existing files like `rsync
--ignore-existing`
does. In that regard I would be surprised if skipping files would result in an
error.
Well, I would understand if there'd be a '--no-clobber=fail' option.
Agreed we should improve the docs a bit for this option.
I'll apply this at least:
diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 1f8b356d1..bf0f424d3 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -9057,6 +9057,8 @@ Do not overwrite an existing file; silently fail instead.
This option overrides a previous
@option{-i} option. This option is mutually exclusive with @option{-b} or
@option{--backup} option.
+See also the @option{--update=none} option which will
+skip existing files but not fail.
@item -P
@itemx --no-dereference
diff --git a/src/cp.c b/src/cp.c
index 04a5cbee3..3ccc4c4e6 100644
--- a/src/cp.c
+++ b/src/cp.c
@@ -192,8 +192,8 @@ Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY.\n\
-L, --dereferencealways follow symbolic links in SOURCE\n\
"), stdout);
fputs (_("\
- -n, --no-clobber do not overwrite an existing file (overrides
a\n\
- -u or previous -i option). See also
--update\n\
+ -n, --no-clobber ensure no existing files overwritten, and
fail\n\
+ silently instead. See also --update\n\
"), stdout);
fputs (_("\
-P, --no-dereference never follow symbolic links in SOURCE\n\
As Kamil added the option in 2009, I'd assume that the same patch was already
active in RHEL versions for quite some longer time.
Now changing the exit code feels kind of rough.
Well RHEL 6 came out a bit after (2010), and had the --no-clobber change,
while RHEL 5 before that did not.
Taking about distros, it's worth noting that the change is Fedora 39
which has been released for a month now.
We'll keep a close eye on issues, but haven't heard much as
of yet at least.
Therefore, from a pure user's perspective and regarding many years of
precedence,
I am 80:20 for reverting the exit code change.
Thanks for your thoughts,
appreciated as always.
cheers,
Pádraig
