[openstack-dev] [Oslo] Change ListOpt and DictOpt default values
Greetings,
I'd like to propose to change both ListOpt and DictOpt default values
to [] and {} respectively. These values are, IMHO, saner defaults than
None for this 2 options and behavior won't be altered - unles `is not
None` is being used.
Since I may be missing some history, I'd like to ask if there's a
reason why None was kept as the default `default` value for this 2 options?
As mentioned above, this change may be backward incompatible in cases
like:
if conf.my_list_opt is None:
Does anyone if there are cases like this?
Also, I know it is possible to do:
cfg.ListOpt('option', default=[])
This is not terrible, TBH, but it doesn't feel right. I've made the
mistake to ignore the `default` keyword myself, although I know `[]`
is not the default option for `ListOpt`. As already said, I'd expect
`[]` to be the default, non-set value for `ListOpt`.
Thoughts?
Cheers,
FF
P.S: I'm not sure I'll make it to tomorrows meeting so, I starting the
discussion here made more sense.
--
@flaper87
Flavio Percoco
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Re: [openstack-dev] [Oslo] Change ListOpt and DictOpt default values
On Thu, Oct 10 2013, Flavio Percoco wrote: This is not terrible, TBH, but it doesn't feel right. I've made the mistake to ignore the `default` keyword myself, although I know `[]` is not the default option for `ListOpt`. As already said, I'd expect `[]` to be the default, non-set value for `ListOpt`. Thoughts? Sounds like a good idea; I can't think of any con. -- Julien Danjou /* Free Software hacker * independent consultant http://julien.danjou.info */ signature.asc Description: PGP signature ___ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
Re: [openstack-dev] [Oslo] Change ListOpt and DictOpt default values
Flavio, sounds good to me. -- dims On Thu, Oct 10, 2013 at 8:46 AM, Julien Danjou jul...@danjou.info wrote: On Thu, Oct 10 2013, Flavio Percoco wrote: This is not terrible, TBH, but it doesn't feel right. I've made the mistake to ignore the `default` keyword myself, although I know `[]` is not the default option for `ListOpt`. As already said, I'd expect `[]` to be the default, non-set value for `ListOpt`. Thoughts? Sounds like a good idea; I can't think of any con. -- Julien Danjou /* Free Software hacker * independent consultant http://julien.danjou.info */ ___ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev -- Davanum Srinivas :: http://davanum.wordpress.com ___ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
Re: [openstack-dev] [Oslo] Change ListOpt and DictOpt default values
On 2013-10-10 07:40, Flavio Percoco wrote:
Greetings,
I'd like to propose to change both ListOpt and DictOpt default values
to [] and {} respectively. These values are, IMHO, saner defaults than
None for this 2 options and behavior won't be altered - unles `is not
None` is being used.
Since I may be missing some history, I'd like to ask if there's a
reason why None was kept as the default `default` value for this 2
options?
As mentioned above, this change may be backward incompatible in cases
like:
if conf.my_list_opt is None:
Does anyone if there are cases like this?
Also, I know it is possible to do:
cfg.ListOpt('option', default=[])
This is not terrible, TBH, but it doesn't feel right. I've made the
mistake to ignore the `default` keyword myself, although I know `[]`
is not the default option for `ListOpt`. As already said, I'd expect
`[]` to be the default, non-set value for `ListOpt`.
Thoughts?
Cheers,
FF
P.S: I'm not sure I'll make it to tomorrows meeting so, I starting the
discussion here made more sense.
Since this is technically an incompatible API change, would a major
version bump be needed for oslo.config if we did this? Maybe nobody's
relying on the existing behavior, but since oslo.config is a released
library its API is supposed to be stable.
-Ben
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Re: [openstack-dev] [Oslo] Change ListOpt and DictOpt default values
On 10/10/2013 09:45 AM, Ben Nemec wrote:
On 2013-10-10 07:40, Flavio Percoco wrote:
Greetings,
I'd like to propose to change both ListOpt and DictOpt default values
to [] and {} respectively. These values are, IMHO, saner defaults than
None for this 2 options and behavior won't be altered - unles `is not
None` is being used.
Since I may be missing some history, I'd like to ask if there's a
reason why None was kept as the default `default` value for this 2
options?
As mentioned above, this change may be backward incompatible in cases
like:
if conf.my_list_opt is None:
Does anyone if there are cases like this?
Also, I know it is possible to do:
cfg.ListOpt('option', default=[])
This is not terrible, TBH, but it doesn't feel right. I've made the
mistake to ignore the `default` keyword myself, although I know `[]`
is not the default option for `ListOpt`. As already said, I'd expect
`[]` to be the default, non-set value for `ListOpt`.
Thoughts?
Cheers,
FF
P.S: I'm not sure I'll make it to tomorrows meeting so, I starting the
discussion here made more sense.
Since this is technically an incompatible API change, would a major
version bump be needed for oslo.config if we did this? Maybe nobody's
relying on the existing behavior, but since oslo.config is a released
library its API is supposed to be stable.
+1. boto just broke our builds by making an incompatible API change in
version 2.14. We can't make every project in the world not do that, but
we sure should avoid doing it ourselves.
--
David Ripton Red Hat drip...@redhat.com
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Re: [openstack-dev] [Oslo] Change ListOpt and DictOpt default values
Hi Flavio,
On Thu, 2013-10-10 at 14:40 +0200, Flavio Percoco wrote:
Greetings,
I'd like to propose to change both ListOpt and DictOpt default values
to [] and {} respectively. These values are, IMHO, saner defaults than
None for this 2 options and behavior won't be altered - unles `is not
None` is being used.
Since I may be missing some history, I'd like to ask if there's a
reason why None was kept as the default `default` value for this 2 options?
As mentioned above, this change may be backward incompatible in cases
like:
if conf.my_list_opt is None:
Does anyone if there are cases like this?
I'd need a lot of persuasion that this won't break some use of
oslo.config somewhere. Not why would anyone do that? hand-waving.
People do all sorts of weird stuff with APIs.
If people really think this is a big issue, I'd make it opt-in. Another
boolean flag like the recently added validate_default_values.
As regards bumping the major number and making incompatible changes - I
think we should only consider that when there's a tonne of legacy
compatibility stuff that we want to get rid of. For example, if we had a
bunch of opt-in flags like these, then there'd come a point where we'd
say let's do 2.0 and clean those up. However, doing such a thing is
disruptive and I'd only be in favour of it if the backwards compat
support was really getting in our way.
Thanks,
Mark.
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Re: [openstack-dev] [Oslo] Change ListOpt and DictOpt default values
On 10/10/13 15:29 +0100, Mark McLoughlin wrote:
Hi Flavio,
On Thu, 2013-10-10 at 14:40 +0200, Flavio Percoco wrote:
Greetings,
I'd like to propose to change both ListOpt and DictOpt default values
to [] and {} respectively. These values are, IMHO, saner defaults than
None for this 2 options and behavior won't be altered - unles `is not
None` is being used.
Since I may be missing some history, I'd like to ask if there's a
reason why None was kept as the default `default` value for this 2 options?
As mentioned above, this change may be backward incompatible in cases
like:
if conf.my_list_opt is None:
Does anyone if there are cases like this?
I'd need a lot of persuasion that this won't break some use of
oslo.config somewhere. Not why would anyone do that? hand-waving.
People do all sorts of weird stuff with APIs.
Agreed, that's what I'd like to find out, I'm sure there are cases
like:
for item in conf.my_list_opt:
Which means that they're already using `default=[]` but I'm not 100%
sure about the backward incompatible change I mentioned.
If people really think this is a big issue, I'd make it opt-in. Another
boolean flag like the recently added validate_default_values.
TBH, I don't think this will be a really big issue but I'll do more
research on this if we agree the change makes sense. AFAICT, usages
like the one mentioned may result in something like:
if conf.my_list_opt is None:
val = [] # Or something else
# OR
val = conf.my_list_opt or []
In which cases, using `default=[]` would had made more sense. I
haven't done a lot of research on this yet.
As regards bumping the major number and making incompatible changes - I
think we should only consider that when there's a tonne of legacy
compatibility stuff that we want to get rid of. For example, if we had a
bunch of opt-in flags like these, then there'd come a point where we'd
say let's do 2.0 and clean those up. However, doing such a thing is
disruptive and I'd only be in favour of it if the backwards compat
support was really getting in our way.
Agreed here as well!
Cheers,
FF
--
@flaper87
Flavio Percoco
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