Dear All,
thanks a lot for the replies, and for discussing the topic in the TC call. You also pointed out that the e-mail subject was wrong: it should have referred to âtype composition hierarchiesâ,
or something similar, but definitely not âinheritance hierarchiesâ (hence my reference to the inheritance-related section of TOSCA v2.0 was also inadequate).
Having read the minutes from the August 18 call as well, I believe that you concluded that (1) yes,
property_1 will have the value
value_1, and (2) this behavior will be explicitly described and demonstrated with an in the v2.0 specs.
Greetings,
GÃbor
From: Chris Lauwers <lauwers@ubicity.com>
Sent: Tuesday, August 18, 2020 5:55 PM
To: Calin Curescu <calin.curescu@ericsson.com>; Tal Liron <tliron@redhat.com>
Cc: Marton, Gabor (Nokia - HU/Budapest) <gabor.marton@nokia.com>; tosca@lists.oasis-open.org; Nemeth, Denes (Nokia - HU/Budapest) <denes.nemeth@nokia.com>; Nguyenphu, Thinh (Nokia - US/Dallas) <thinh.nguyenphu@nokia.com>
Subject: RE: [tosca] Propagation of default values in inheritance hierarchies: standpoint for TOSCA v1.2/v1.3?
Yes, but this is not a âderivationâ scenario. Itâs just a simple âassignmentâ scenario.
Chris
From: Calin Curescu <calin.curescu@ericsson.com>
Sent: Tuesday, August 18, 2020 8:48 AM
To: Tal Liron <tliron@redhat.com>; Chris Lauwers <lauwers@ubicity.com>
Cc: Marton, Gabor (Nokia - HU/Budapest) <gabor.marton@nokia.com>; tosca@lists.oasis-open.org; Nemeth, Denes (Nokia - HU/Budapest) <denes.nemeth@nokia.com>; Nguyenphu, Thinh (Nokia - US/Dallas) <thinh.nguyenphu@nokia.com>
Subject: Re: [tosca] Propagation of default values in inheritance hierarchies: standpoint for TOSCA v1.2/v1.3?
Hi,
In TOSCA 2.0 these rules are stated in the section: 4.2.5.1 General derivation and refinement rules:
https://docs.oasis-open.org/tosca/TOSCA/v2.0/csd02/TOSCA-v2.0-csd02.html#_Toc44418531
BR/C
Well, not quite an inheritance issue but a "propagation" issue. I guess the question is whether by encapsulating one data type inside another the default properties would also be included. I'm sure we all agree that the
answer is yes.
It's not immediately obvious, so I would recommend adding an explanation in the spec, possibly with an example.
Iâm not sure there is a âpropagationâ (or inheritance) issue here. This seems to be a very straightforward example where (as Gabor states) the resulting value
is indeed 1.
Chris
As you point out, the spec wasn't entirely clear up to 1.3. I think somewhere it does point out that all keywords are inherited, but I can't find it right now...
In any case, I think all popular current implementations inherit the "default" keyword, as it does seem to be natural and intended.
Dear TOSCA Experts,
in TOSCA v1.2 and v1.3, is the below
example node template valid i.e. does its (required) property
complex_1.example_1.property_1 have the value
value_1?
data_types:
provider.datatypes.Example:
derived_from: tosca.datatypes.Root
properties:
property_1:
type: string
default: value_1
provider.datatypes.Complex:
derived_from: tosca.datatypes.Root
properties:
example_1:
type: provider.datatypes.Example
node_types:
provider.nodes.Example:
derived_from: tosca.nodes.Root
properties:
complex_1:
type: provider.datatypes.Complex
topology_template:
node_templates:
example:
type: provider.nodes.Example
Propagation of default values is not explicitly covered by TOSCA v1.2/v1.3.
In the TOSCA
v2.0 draft, I can see one sentence that makes me answer the above question affirmatively: âdefault: a new definition is unrestricted and will overwrite the one
inherited from the property definition in the parent entity type definition" (4.4.5.5 Refinement rules).
Greetings,
GÃbor
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