Re: git: 2f036705f337 - main - Document the two recent newsyslog(8) change (-c option and <compress> configuration option).

On 29 Dec 2023, at 2:46, Xin LI wrote:

> The branch main has been updated by delphij:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=2f036705f337f61cee5a3b4f570b023c3da29895
>
> commit 2f036705f337f61cee5a3b4f570b023c3da29895
> Author:     Xin LI <delphij@FreeBSD.org>
> AuthorDate: 2023-12-29 08:45:52 +0000
> Commit:     Xin LI <delphij@FreeBSD.org>
> CommitDate: 2023-12-29 08:45:52 +0000
>
>     Document the two recent newsyslog(8) change (-c option and <compress>
>     configuration option).
> ---
>  RELNOTES | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>
> diff --git a/RELNOTES b/RELNOTES
> index 509cf36c070e..adb9ca67aa0c 100644
> --- a/RELNOTES
> +++ b/RELNOTES
> @@ -10,6 +10,26 @@ newline.  Entries should be separated by a newline.
>
>  Changes to this file should not be MFCed.
>
> +61174ad88e33:
> +	newsyslog(8) now supports specifying a global compression method directly
> +	at the beginning of the newsyslog.conf file, which will make newsyslog(8)
> +	to behave like the corresponding option was passed to the newly added
> +	'-c' option. For example:
> +
> +	<compress> none
> +
> +906748d208d3:
> +	newsyslog(8) now accepts a new option, '-c' which overrides all historical
> +	compression flags by treating their meaning as "treat the file as compressible"
> +	rather than "compress the file with that specific method."
> +
> +	The following choices are available:
> +	 * none: Do not compress, regardless of flag.
> +	 * legacy: Historical behavior (J=bzip2, X=xz, Y=zstd, Z=gzip).
> +	 * bzip2, xz, zstd, gzip: apply the specified compression method.
> +
> +	We plan to change the default to 'none' in FreeBSD 15.0.

Sorry not to have noticed this in the review; it was only when I saw this
message that it sunk in that we now have *three* ways to specify compression,
and I'm not even sure what the precedence is.  I would have thought that
<compress> would replace -c.  It's a mess if the config file has entries
that specify J and X flags as well as none, the config file has
<compress> zstd, and the -c option is given as well.  We now have a knob
to override the knob to override a knob. The only reason to keep -c that
I can think of is to specify a different compression in a single invocation,
but as noted, changing compression requires manual operations that make
it unreasonable to change it invocation by invocation.

Also, using the -c option or <compress> (except with legacy) loses the
ability to specify different compression types for different files.
People have objected to the term "legacy" as well.

I still think it would be much better to add an option letter to select
the default compression as specified by <compress>.  This would eliminate
the need for "legacy", and it would add the ability to have both a global
default and an exception.  I think the redefinition of the existing flags
to have different meanings if <compress> is given is messy.

The entry for -c says that we plan to change the default to "none" in 15.0.
Hopefully that would be done via <compress> and not -c.  However, there
was significant pushback on "none" being the default.

		Mike