virsh: Require --xpath for dumpxml

[PATCH] virsh: Require --xpath for dumpxml

Posted by Michal Privoznik 3 years, 7 months ago

Historically, the dumpxml command reject any unknown arguments,
for instance:

    virsh dumpxml fedora xxx

However, after v8.5.0-rc1~31 the second argument ('xxx') is
treated as an XPath, but it's not that clearly visible.
Therefore, require the --xpath switch, like this:

    virsh dumpxml fedora --xpath xxx

Yes, this breaks already released virsh, but I think we can argue
that the pool of users of this particular function is very small.
The sooner we do this change, the better.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2103524
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---
 tools/virsh-domain.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
index 43034f2f81..a181ae005f 100644
--- a/tools/virsh-domain.c
+++ b/tools/virsh-domain.c
@@ -10461,6 +10461,7 @@ static const vshCmdOptDef opts_dumpxml[] = {
     },
     {.name = "xpath",
      .type = VSH_OT_STRING,
+     .flags = VSH_OFLAG_REQ_OPT,
      .completer = virshCompleteEmpty,
      .help = N_("xpath expression to filter the XML document")
     },
-- 
2.35.1

Re: [PATCH] virsh: Require --xpath for dumpxml

Posted by Daniel P. Berrangé 3 years, 7 months ago

On Fri, Jul 08, 2022 at 12:49:13PM +0200, Michal Privoznik wrote:
> Historically, the dumpxml command reject any unknown arguments,
> for instance:
> 
>     virsh dumpxml fedora xxx
> 
> However, after v8.5.0-rc1~31 the second argument ('xxx') is
> treated as an XPath, but it's not that clearly visible.
> Therefore, require the --xpath switch, like this:
> 
>     virsh dumpxml fedora --xpath xxx
> 
> Yes, this breaks already released virsh, but I think we can argue
> that the pool of users of this particular function is very small.
> The sooner we do this change, the better.
> 
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2103524
> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
> ---
>  tools/virsh-domain.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
> index 43034f2f81..a181ae005f 100644
> --- a/tools/virsh-domain.c
> +++ b/tools/virsh-domain.c
> @@ -10461,6 +10461,7 @@ static const vshCmdOptDef opts_dumpxml[] = {
>      },
>      {.name = "xpath",
>       .type = VSH_OT_STRING,
> +     .flags = VSH_OFLAG_REQ_OPT,
>       .completer = virshCompleteEmpty,
>       .help = N_("xpath expression to filter the XML document")
>      },

Opps, shouldn't we do the same change for all the other 'xpath'
parameters.


With regards,
Daniel
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Re: [PATCH] virsh: Require --xpath for dumpxml

Posted by Michal Prívozník 3 years, 7 months ago

On 7/8/22 13:23, Daniel P. Berrangé wrote:
> On Fri, Jul 08, 2022 at 12:49:13PM +0200, Michal Privoznik wrote:
>> Historically, the dumpxml command reject any unknown arguments,
>> for instance:
>>
>>     virsh dumpxml fedora xxx
>>
>> However, after v8.5.0-rc1~31 the second argument ('xxx') is
>> treated as an XPath, but it's not that clearly visible.
>> Therefore, require the --xpath switch, like this:
>>
>>     virsh dumpxml fedora --xpath xxx
>>
>> Yes, this breaks already released virsh, but I think we can argue
>> that the pool of users of this particular function is very small.
>> The sooner we do this change, the better.
>>
>> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2103524
>> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
>> ---
>>  tools/virsh-domain.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
>> index 43034f2f81..a181ae005f 100644
>> --- a/tools/virsh-domain.c
>> +++ b/tools/virsh-domain.c
>> @@ -10461,6 +10461,7 @@ static const vshCmdOptDef opts_dumpxml[] = {
>>      },
>>      {.name = "xpath",
>>       .type = VSH_OT_STRING,
>> +     .flags = VSH_OFLAG_REQ_OPT,
>>       .completer = virshCompleteEmpty,
>>       .help = N_("xpath expression to filter the XML document")
>>      },
> 
> Opps, shouldn't we do the same change for all the other 'xpath'
> parameters.
> 

I guess we should. But I worry that we might break some users scripts.
But I guess if you're okay with it then so am I.

Michal

Re: [PATCH] virsh: Require --xpath for dumpxml

Posted by Daniel P. Berrangé 3 years, 7 months ago

On Fri, Jul 08, 2022 at 01:58:08PM +0200, Michal Prívozník wrote:
> On 7/8/22 13:23, Daniel P. Berrangé wrote:
> > On Fri, Jul 08, 2022 at 12:49:13PM +0200, Michal Privoznik wrote:
> >> Historically, the dumpxml command reject any unknown arguments,
> >> for instance:
> >>
> >>     virsh dumpxml fedora xxx
> >>
> >> However, after v8.5.0-rc1~31 the second argument ('xxx') is
> >> treated as an XPath, but it's not that clearly visible.
> >> Therefore, require the --xpath switch, like this:
> >>
> >>     virsh dumpxml fedora --xpath xxx
> >>
> >> Yes, this breaks already released virsh, but I think we can argue
> >> that the pool of users of this particular function is very small.
> >> The sooner we do this change, the better.
> >>
> >> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2103524
> >> Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
> >> ---
> >>  tools/virsh-domain.c | 1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> diff --git a/tools/virsh-domain.c b/tools/virsh-domain.c
> >> index 43034f2f81..a181ae005f 100644
> >> --- a/tools/virsh-domain.c
> >> +++ b/tools/virsh-domain.c
> >> @@ -10461,6 +10461,7 @@ static const vshCmdOptDef opts_dumpxml[] = {
> >>      },
> >>      {.name = "xpath",
> >>       .type = VSH_OT_STRING,
> >> +     .flags = VSH_OFLAG_REQ_OPT,
> >>       .completer = virshCompleteEmpty,
> >>       .help = N_("xpath expression to filter the XML document")
> >>      },
> > 
> > Opps, shouldn't we do the same change for all the other 'xpath'
> > parameters.
> > 
> 
> I guess we should. But I worry that we might break some users scripts.
> But I guess if you're okay with it then so am I.

It was documented as --xpath in the man page.  That you could give it
positionally was an oversight of mine, thanks to our crazy homegrown
CLI parser behaviour. Did I mention I wished we just used getopt...

With regards,
Daniel
-- 
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