Re: [gentoo-dev] Re: RFC: intel-sdp-r1.eclass

[Michał Górny]

On Tue, 16 Feb 2016 22:48:08 -0600
Ryan Hill <rhill@g.o> wrote:

> On Mon, 15 Feb 2016 15:35:12 +0100
> Michał Górny <mgorny@g.o> wrote:
> > On Mon, 15 Feb 2016 14:37:41 +0100
> > "Justin Lecher (jlec)" <jlec@g.o> wrote:
> > > On 15/02/16 13:59, Michał Górny wrote:
> > > > On Mon, 15 Feb 2016 09:16:53 +0100
> > > > "Justin Lecher (jlec)" <jlec@g.o> wrote:
> > > >> _isdp_big-warning() {
> > > >> 	debug-print-function ${FUNCNAME} "${@}"
> > > >> 	case ${1} in
> > > >> 		pre-check )
> > > >> 			echo ""
> > > > Don't mix echo with ewarn.
> > > Why?
> > Because they won't go through the same output channels.
>
> That's kinda the point.  You want a blank (unstarred) space
> to separate out the "important" messages from the generic
> spew put out by the package manager/eclasses/build system
> that you have no control over.

This is not just that. Different output channels mean that:

- some of them can be turned off. In this case, you end up with empty
  lines and no message.

- There is no guarantee of correct output order! The empty lines may
  move randomly over the text.

- When the function happens to be used in $(), part of the output will
  be collected (not that it's 100% valid concern right now because
  EAPI 6 doesn't guarantee e* using stderr yet).

> If you have several different messages you want a blank space
> in between them so you can use e* to create whitespace within
> the message to avoid the wall of text syndrome while still
> making it clear where it begins and ends.
>
> Let's take openrc for example (not picking on anyone, it's just
> the last package with a bunch of different post-install messages
> I happened to emerge).
>
> Currently:
>
>  * The OpenRC dependency data has already been migrated.
>  * Caching service dependencies ... [ ok ]
>  * In this version of OpenRC, the loopback interface no longer
>  * satisfies the net virtual.
>  * If you have services now which do not start because of this,
>  * They can be fixed by adding rc_need="!net"
>  * to the /etc/conf.d/<servicename> file.
>  * You should also file a bug against the service asking that
>  * need net be dropped from the dependencies.
>  * The bug you file should block the following tracker:
>  * https://bugs.gentoo.org/show_bug.cgi?id=439092
>  *
>  * Bug https://bugs.gentoo.org/show_bug.cgi?id=427996 was not
>  * fixed correctly in earlier versions of OpenRC.
>  * The correct fix is implemented in this version, but that
>  * means netmount needs to be added to the default runlevel if
>  * you are using nfs file systems.
>  *
>  * You should now update all files in /etc, using etc-update
>  * or equivalent before restarting any services or this host.
>
> This is pretty much unreadable to me.
>
> Better:
>
>  * The OpenRC dependency data has already been migrated.
>  * Caching service dependencies ... [ ok ]
>  *
>  * In this version of OpenRC, the loopback interface no longer
>  * satisfies the net virtual.
>  *
>  * If you have services now which do not start because of this,
>  * They can be fixed by adding rc_need="!net"
>  * to the /etc/conf.d/<servicename> file.
>  *
>  * You should also file a bug against the service asking that
>  * need net be dropped from the dependencies.
>  *
>  * The bug you file should block the following tracker:
>  * https://bugs.gentoo.org/show_bug.cgi?id=439092
>  *
>  * Bug https://bugs.gentoo.org/show_bug.cgi?id=427996 was not
>  * fixed correctly in earlier versions of OpenRC.
>  *
>  * The correct fix is implemented in this version, but that
>  * means netmount needs to be added to the default runlevel if
>  * you are using nfs file systems.
>  *
>  * You should now update all files in /etc, using etc-update
>  * or equivalent before restarting any services or this host.
>
> This is better but you still have to read the whole thing to
> make sure you didn't miss anything important.
>
> Even better:
>
>  * The OpenRC dependency data has already been migrated.
>  * Caching service dependencies ... [ ok ]
>
>  * In this version of OpenRC, the loopback interface no longer
>  * satisfies the net virtual.
>  *
>  * If you have services now which do not start because of this,
>  * They can be fixed by adding rc_need="!net"
>  * to the /etc/conf.d/<servicename> file.
>  *
>  * You should also file a bug against the service asking that
>  * need net be dropped from the dependencies.
>  * The bug you file should block the following tracker:
>  *
>  * https://bugs.gentoo.org/show_bug.cgi?id=439092
>
>  * Bug https://bugs.gentoo.org/show_bug.cgi?id=427996 was not
>  * fixed correctly in earlier versions of OpenRC.
>  *
>  * The correct fix is implemented in this version, but that
>  * means netmount needs to be added to the default runlevel if
>  * you are using nfs file systems.
>
>  * You should now update all files in /etc, using etc-update
>  * or equivalent before restarting any services or this host.
>
> Here I can read the first line of the second block and know I can
> skip the next 12 lines without missing anything.  The next block
> isn't worded the greatest, but that's beside the point.  And now
> I get an important message at the end that I previously never
> noticed because tl;dr.
>
> You're right that using echo means the whitespace doesn't get
> saved by the elog system.  A while back someone proposed we
> add espace for exactly this reason but IIRC they were laughed
> down, which is a shame.

So... to summarize your point. You shouldn't use the correct function
that is saved in elog which is primary way of getting info because you
find it more convenient to have empty non-'starred' lines that don't
actually get to elog and make elog a mess?

If you really don't like empty 'starred' lines (and I actually like
them since they make separation between packages cleaner), why not
submit a patch for Portage and make 'elog' with no arguments output log
line without a star? That's a trivial solution that doesn't require
extra functions for the sake of inventing elogspace, ewarnspace, ...

-- 
Best regards,
Michał Górny
<http://dev.gentoo.org/~mgorny/>