Use of "?" for help has been deprecated for 8 years, can we drop it?

Use of "?" for help has been deprecated for 8 years, can we drop it?

[Markus Armbruster]

We deprecated "?" more than eight years ago.  We didn't have a
deprecation process back then, but we did purge "?" from the
documentation and from help texts.  Can we finally drop it?

I'm asking because there is a patch on the list that bypasses
is_help_option() to not add deprecated "?" to a new place: "[PATCH v2
1/4] keyval: Parse help options".



commit c8057f951d64de93bfd01569c0a725baa9f94372
Author: Peter Maydell <peter.maydell@linaro.org>
Date:   Thu Aug 2 13:45:54 2012 +0100

    Support 'help' as a synonym for '?' in command line options
    
    For command line options which permit '?' meaning 'please list the
    permitted values', add support for 'help' as a synonym, by abstracting
    the check out into a helper function.
    
    This change means that in some cases where we were being lazy in
    our string parsing, "?junk" will now be rejected as an invalid option
    rather than being (undocumentedly) treated the same way as "?".
    
    Update the documentation to use 'help' rather than '?', since '?'
    is a shell metacharacter and thus prone to fail confusingly if there
    is a single character filename in the current working directory and
    the '?' has not been escaped. It's therefore better to steer users
    towards 'help', though '?' is retained for backwards compatibility.
    
    We do not, however, update the output of the system emulator's -help
    (or any documentation autogenerated from the qemu-options.hx which
    is the source of the -help text) because libvirt parses our -help
    output and will break. At a later date when QEMU provides a better
    interface so libvirt can avoid having to do this, we can update the
    -help text too.
    
    Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
    Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

commit 585f60368f23e6603cf86cfdaeceb89d1169f4b8
Author: Peter Maydell <peter.maydell@linaro.org>
Date:   Thu Oct 4 16:22:01 2012 +0100

    qemu-options.hx: Change from recommending '?' to 'help'
    
    Update the -help output and documentation so that it recommends
    'help' rather than '?' for the various "list valid values for this
    option" cases. '?' is deprecated (as it can fail confusingly if
    not quoted), so it's better to steer users towards 'help'. ('?'
    still works, for backwards compatibility.)
    
    This is the -help option part of the change otherwise done in
    commit c8057f9, since we are now past release 1.2 and free to
    change our help text without worrying about breaking libvirt.
    
    Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
    Reviewed-by: Eric Blake <eblake@redhat.com>
    Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

Re: Use of "?" for help has been deprecated for 8 years, can we drop it?

[Thomas Huth]

On 01/10/2020 12.35, Markus Armbruster wrote:
> We deprecated "?" more than eight years ago.  We didn't have a
> deprecation process back then, but we did purge "?" from the
> documentation and from help texts.  Can we finally drop it?

It's not mentioned in docs/system/deprecated.rst yet, so it is not
officially deprecated yet. Provide a patch to add it to the list there,
then you can remove it after two releases.

 Thomas

Re: Use of "?" for help has been deprecated for 8 years, can we drop it?

[Peter Maydell]

On Thu, 1 Oct 2020 at 11:35, Markus Armbruster <armbru@redhat.com> wrote:
>
> We deprecated "?" more than eight years ago.  We didn't have a
> deprecation process back then, but we did purge "?" from the
> documentation and from help texts.  Can we finally drop it?

Is it really that terrible a burden to support having an
alias for 'help' ?

thanks
-- PMM

Re: Use of "?" for help has been deprecated for 8 years, can we drop it?

[Eric Blake]

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On 10/1/20 5:35 AM, Markus Armbruster wrote:
> We deprecated "?" more than eight years ago.  We didn't have a
> deprecation process back then, but we did purge "?" from the
> documentation and from help texts.  Can we finally drop it?
> 
> I'm asking because there is a patch on the list that bypasses
> is_help_option() to not add deprecated "?" to a new place: "[PATCH v2
> 1/4] keyval: Parse help options".
> 

Did we ever issue a warning when it was used?  It's easier to argue that
it can be dropped if users had notice of some form or another.  That
said, I'm not heartbroken if we yank it immediately instead of letting
it live for 2 more releases.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


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Re: Use of "?" for help has been deprecated for 8 years, can we drop it?

[Kevin Wolf]

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Am 01.10.2020 um 15:06 hat Eric Blake geschrieben:
> On 10/1/20 5:35 AM, Markus Armbruster wrote:
> > We deprecated "?" more than eight years ago.  We didn't have a
> > deprecation process back then, but we did purge "?" from the
> > documentation and from help texts.  Can we finally drop it?
> > 
> > I'm asking because there is a patch on the list that bypasses
> > is_help_option() to not add deprecated "?" to a new place: "[PATCH v2
> > 1/4] keyval: Parse help options".
> > 
> 
> Did we ever issue a warning when it was used?  It's easier to argue that
> it can be dropped if users had notice of some form or another.  That
> said, I'm not heartbroken if we yank it immediately instead of letting
> it live for 2 more releases.

A deprecation warning for a help option would somehow feel strange.

I would consider this a human-only interface that can be changed at
will, like HMP syntax.

Kevin

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Re: Use of "?" for help has been deprecated for 8 years, can we drop it?

[BALATON Zoltan via]

On Thu, 1 Oct 2020, Eric Blake wrote:
> On 10/1/20 5:35 AM, Markus Armbruster wrote:
>> We deprecated "?" more than eight years ago.  We didn't have a
>> deprecation process back then, but we did purge "?" from the
>> documentation and from help texts.  Can we finally drop it?
>>
>> I'm asking because there is a patch on the list that bypasses
>> is_help_option() to not add deprecated "?" to a new place: "[PATCH v2
>> 1/4] keyval: Parse help options".
>>
>
> Did we ever issue a warning when it was used?  It's easier to argue that
> it can be dropped if users had notice of some form or another.  That
> said, I'm not heartbroken if we yank it immediately instead of letting
> it live for 2 more releases.

How about keeping it as a convenience? I find it easier to type ? than 
help and often use it instead. It's sufficiently hidden to not cause any 
confusion for those who don't know and convenient for those who know. I 
agree with Peter that it should not be something that causes that much 
trouble that it would need to be removed immediately (or even in the 
future).

Regrads,
BALATON Zoltan

Re: Use of "?" for help has been deprecated for 8 years, can we drop it?

[Thomas Huth]

On 01/10/2020 15.17, Kevin Wolf wrote:
> Am 01.10.2020 um 15:06 hat Eric Blake geschrieben:
>> On 10/1/20 5:35 AM, Markus Armbruster wrote:
>>> We deprecated "?" more than eight years ago.  We didn't have a
>>> deprecation process back then, but we did purge "?" from the
>>> documentation and from help texts.  Can we finally drop it?
>>>
>>> I'm asking because there is a patch on the list that bypasses
>>> is_help_option() to not add deprecated "?" to a new place: "[PATCH v2
>>> 1/4] keyval: Parse help options".
>>>
>>
>> Did we ever issue a warning when it was used?  It's easier to argue that
>> it can be dropped if users had notice of some form or another.  That
>> said, I'm not heartbroken if we yank it immediately instead of letting
>> it live for 2 more releases.
> 
> A deprecation warning for a help option would somehow feel strange.
> 
> I would consider this a human-only interface that can be changed at
> will, like HMP syntax.

I'm not so sure ... for example we use "-device help" in the qemu-iotest
scripts, so other people out there might use "-device ?" in their
scripts, too, to check for the availability of devices... so IMHO we
should follow the deprecation process properly here.

 Thomas

Re: Use of "?" for help has been deprecated for 8 years, can we drop it?

[Christian Borntraeger]

On 01.10.20 13:20, Peter Maydell wrote:
> On Thu, 1 Oct 2020 at 11:35, Markus Armbruster <armbru@redhat.com> wrote:
>>
>> We deprecated "?" more than eight years ago.  We didn't have a
>> deprecation process back then, but we did purge "?" from the
>> documentation and from help texts.  Can we finally drop it?
> 
> Is it really that terrible a burden to support having an
> alias for 'help' ?

I agree. Having the "?" is really convenient. 

Re: Use of "?" for help has been deprecated for 8 years, can we drop it?

[Kevin Wolf]

Am 01.10.2020 um 17:23 hat Christian Borntraeger geschrieben:
> 
> 
> On 01.10.20 13:20, Peter Maydell wrote:
> > On Thu, 1 Oct 2020 at 11:35, Markus Armbruster <armbru@redhat.com> wrote:
> >>
> >> We deprecated "?" more than eight years ago.  We didn't have a
> >> deprecation process back then, but we did purge "?" from the
> >> documentation and from help texts.  Can we finally drop it?
> > 
> > Is it really that terrible a burden to support having an
> > alias for 'help' ?
> 
> I agree. Having the "?" is really convenient. 

If people actually care about "?", can one of you send a patch to remove
the comment that declares it deprecated?

Kevin

Re: Use of "?" for help has been deprecated for 8 years, can we drop it?

[Gerd Hoffmann]

  Hi,

> > Did we ever issue a warning when it was used?  It's easier to argue that
> > it can be dropped if users had notice of some form or another.  That
> > said, I'm not heartbroken if we yank it immediately instead of letting
> > it live for 2 more releases.
> 
> How about keeping it as a convenience? I find it easier to type ? than help
> and often use it instead.

Well, ? has the problem that it is a shell glob char[1], which is for me
enough reason to avoid it at least standalone ("-device ?").  When
querying properties ("-device foo,?") it is much less likely to trip you
up.

On the other hand I don't see any harm in keeping it.  What would we
save when we drop it?  Given we already have a helper function to check
it is only 2-3 lines of extra code I guess?

take care,
  Gerd

[1] IIRC that was the reason to add "help" in the first place.