Re: [sca-bpel] NEW ISSUE: SBPEL2022 has an incorrect 'MAY' and isnot applied recursively

[Danny van der Rijn <dannyv@tibco.com>]

[changing subject to include issue #]

As we discussed on the call, we need to do 2 things:

1 - decide what it is we actually want the spec to require here
2 - come up with language that specifies that

IMO it will be much easier to do #1 if we don't do #2 at the same time.  I'll take a stab at what it is we want to do, using an illustrative (and pathological) example.

Imagine a process with the following (scopes and) partnerLinks:

Scope1
    shipping
    _shipping_2
    receiving
    _receiving_2
   
Scope2
    _shipping_1
    _receiving_1
   

As context, here's section 2.3:

"It is possible to declare partner links local to a <scope> in WS-BPEL, besides declaring partner links at the <process> level. The names of partner link declared in different <scope> could potentially share the identical name. [SBPEL2019] When multiple partner links share the same name, the scheme defined by [SBPEL2020]-[SBPEL2022] MUST be used to disambiguate different occurrences of partner link declaration.

·          Let "originalName" be the original NCName used in multiple partner link declarations.

·          [SBPEL2020] The introspected component type MUST include services or references corresponding to these partner links with names: "_orginalName_1" to "_orginalName_N". Whether the partner link corresponds to a service or reference does not affect the name used. [SBPEL2021] The number suffixes for the partner links MUST be based on the lexical order of the corresponding partner link occurrences in the process definition.

·          [SBPEL2022] If any "_orginalName_i" (where 1 <= i <= N) is already the name of a partner link declaration in the process definition, additional underscore characters MAY be added at the beginning of all aliases consistently to avoid collision."

I read the above rules as resulting in the following:

Scope1
    shipping         <-  _shipping_1
    _shipping_2   <- __shipping_2_1
    receiving         <- _receiving_1
    _receiving_2   <- __receiving_2_1
   
Scope2
    shipping         <- _shipping_2
    receiving         <- _receiving_2
    _shipping_1   <- __shipping_1_1
    _receiving_1   <- __receiving_1_2


Note:  This solution is not handled in a single-pass.  Would a single-pass solution be preferable?

I'm not sure that this is the prettiest solution, but then again, I'm not sure I care.  I'd welcome other solutions, as well as other interpretations of the text.  However, all that is truly important, IMO, is that we agree on what we want (#1) and then do our best to encode it (#2).  If #2 proves too difficult for our decision on #1, then I propose we change #1.

Danny



Danny van der Rijn wrote:

4A0206B6.5040208@tibco.com" type="cite"> If you're going down to this level of detail, I think you need to be more explicit about what "recursive"  and (where 1 <= i <= N) mean.  Something like

"If any "_originalName_i" (where N is the number of partnerLinks of name 'originalName', 1 <= i <= N) is already the name of a partner link declaration in the process definition, then the smallest number of additional underscore characters MAY  MUST be added at the beginning of all aliases originalNames, consistently to avoid collision, to avoid a collision."



Anish Karmarkar wrote:

4A020327.3070808@oracle.com" type="cite">Title: SBPEL2022 has an incorrect 'MAY' and is not applied recursively

Target: SCA BPEL C&I PR 01

Description:
SBPEL2022 states the following:
"If any "_orginalName_i" (where 1 <= i <= N) is already the name of a partner link declaration in the process definition, additional underscore characters MAY be added at the beginning of all aliases consistently to avoid collision."

'MAY' here means that some runtimes may not choose to do this. We want deterministic names that are independent of the runtime.

It is also possible that after an additional underscore is added at the beginning it still results in a conflict. SBPEL2022 needs to be applied recursive till there is no collision.

Proposal:

Replace SBPEL2022 with --
"If any "_orginalName_i" (where 1 <= i <= N) is already the name of a partner link declaration in the process definition, then an additional underscore characters MAY  MUST be added at the beginning of all aliases names, recursively, consistently to avoid collision, until a collision is avoided."

(alternately, we can say something along the lines of "... additional minimum number of underscore characters that results in no collision MUST be added at the beginning of all names consistently."

-Anish
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