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Re: [PATCH] pager support for command line client

From: Stefan Sperling <stsp_at_elego.de>
Date: Wed, 5 Feb 2014 22:55:37 +0100

On Tue, Feb 04, 2014 at 12:37:45PM +0000, Julian Foad wrote:
> I do like the idea of making the output more user-friendly by using a pager.  But keep it simple.  A pager by default just for help -- fine.  A pager for all commands when producing more than a screenful of output -- fine.  A static list of what commands we 'believe' will produce a lot of output -- no.

I've been using an automatic pager for every svn command for a day now.
I'm starting to believe that we'll have to go with a static list.

Turning on the pager for everything is painful, even if we tell it
to quit itself automatically if the output doesn't fill the screen.

Some problems I've been observing are:

 - Error messages are hidden by the pager even if the svn command
   produces no other output. This can be fixed for many cases by
   starting the pager as late as possible (e.g. before the subcommand
   really starts doing work). But not for all cases. I'm not sure what
   to do here. Perhaps we should pipe stderr to the pager as well?

 - Scripted svn commands (e.g. svn update) that produce more than a
   screenfull of output wait for the user to close the pager (arguably, the
   --non-interactive option should be passed by scripts, but the automatic
   pager can break existing scripts that don't pass this options).
   Of course, I made sure the pager isn't started if stdout is not a
   terminal, but many automated scripts are run in a terminal (e.g. builds).

 - If no output is produced the entire screen is cleared anyway (I
   believe this happens with git, too). This behaviour is probably

Ultimately, I'd be much happier with a default behaviour where commands
that *I* usually pipe into a pager would use an automatic pager during
interactive use. I would guess that this applies to almost everyone.
The question then becomes which commands people usually pipe to a
pager as a matter of habit. Should we try to make such a list or not?

Perhaps the best compromise is to make just 'svn help' use a pager by
default (so users realise that the auto-paging feature exists), and
allow users to enable the automatic pager on a per-subcommand basis
in the configuration file?
Received on 2014-02-05 22:56:21 CET

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