[Libguestfs] [libnbd PATCH v2 4/5] api: Add STRICT_FLAGS to set_strict_mode

[Eric Blake]

On 9/17/20 8:32 AM, Richard W.M. Jones wrote:
> On Fri, Sep 11, 2020 at 04:49:55PM -0500, Eric Blake wrote:
>> The next strict knob: allow the user to pass unknown flags across the
>> wire (this is different than passing a known flag at the wrong time).
>>
>> It is interesting to note that NBD only permits 16 bits of flags, but
>> we have a signature that takes uint32_t; if we wanted, we could pack
>> libnbd-specific flags in the upper bits that the NBD protocol would
>> never see.
> 
> This is fine ACK.
> 
> About the "guard" change: I probably would have put that change in a
> separate commit.  Also you could consider having a default_flags
> parameter to avoid having to set guard = None everywhere, although you
> would still have to make a one-off change to every *_flags.  It would
> look like this:
> 
>    let default_flags = { flag_prefix = ""; guard = None; flags = [] }
>    ...
>    let handshake_flags = {
>      default_flags with
>        flag_prefix = "HANDSHAKE_FLAG";
>        flags = [ ... ]
>    }
> 
> (We already do this with "default_call").  Neither of these is a big deal
> though.

Splitting the patch makes sense.  Also, I _did_ consider the 
'default_flags with' solution before your reply, but only after I had 
written the email.  In the short term, it is no difference in the amount 
of churn (adding one line to every flags definition); but in the long 
term, it is nicer if we ever add more items.  So from that perspective, 
I'll go with that change.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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