> On Oct 19, 2017, at 2:18 PM, Tal Liron <[email protected]> wrote:
>
> Some good questions here. Let me try to break it down,
>
> On Thu, Oct 19, 2017 at 12:39 PM, Steve Baillargeon <
> [email protected]> wrote:
>
>> Node template names must be unique within a given service template.
>>
>
> Yes. Actually, there is an "interesting" issue with this: in YAML, a dict
> could have multiple keys with the same name. What happens in that case is
> that subsequent keys (node template names in this case) override previous
> ones of the same name. So, you can syntactically have two node templates of
> the same name, but only one will count.
>
> We tried to find ways in ARIA to emit an error in this case, but actually
> it's very hard to do because it's a YAML spec issue that allows it.
It sounds like a warning in this case is the minimum “user friendly”
thing to do.
Lots of compilers warn for “multiply (re)defined variable” etc…. In a large
set of templates, its unlikely for a human to realize this is happening.
—Tom
>
>
>> What about the case when ST1 imports ST2 as follows.
>> ST1 has 2 node templates: template A derived from node type X and template
>> B derived from node type Y.
>> ST2 has 1 node template: template A derived from node type Z .
>>
>
> Actually, the "imports" keyword isn't 100% clear in the TOSCA spec. What we
> do in ARIA is merge the dicts, and again identical keys (node template
> names) will override without error. So, the final behavior will be
> undefined.
>
> However, I think that in this particular case ARIA can do something more,
> because we handle merging ourselves (it's not an issue of the YAML spec). I
> have opened a new JIRA about this:
> https://issues.apache.org/jira/browse/ARIA-390
