Re: [linux-lvm] pvscan: bugs in manpage and implementation

[David Teigland <teigland@redhat.com>]

On Mon, Sep 18, 2017 at 02:52:04PM +0700, Tom Hale wrote:
> Hi,
> 
> MAN PAGE
> 
> In http://man7.org/linux/man-pages/man8/pvscan.8.html I see the
> following issues:
> 
> * The string "-a--activate" appears several times. Should be:
>   "-a|--activate"

Yes, that's odd, the | exists in the source, but isn't being printed.
I'll just change to --activate for now.

> * "-a|--activate y|n|ay" is mentioned, but later on:
> "Only ay is applicable." Please remove "y|n|".

Unfortunately --activate is one of those options that was given different
acceptable values depending on the command, and we haven't added a special
case to the code that generates man pages to display it differently.

> PROGRAM
> 
> # pvscan --activate ay
>   Command does not accept option: --activate ay.
> 
> The message is confusing. It would be better to say "--activate requires
> --cache"

Yes, this is a limitation in the new code that matches what you have typed
to a specific command.  All possible commands are now defined here:
https://sourceware.org/git/?p=lvm2.git;a=blob_plain;f=tools/command-lines.in;hb=HEAD

It matches 'pvscan --activate' to the 'pvscan' command (which doesn't
accept -a, thus the error), rather than to the 'pvscan --cache' command
(which does accept -a).