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Bug 316200

Summary:

[otjld] Method bindings in role with binding ambiguity?

Product:

[Tools] Objectteams

Reporter:

Stephan Herrmann <stephan.herrmann>

Component:

OTJ

Assignee:

Stephan Herrmann <stephan.herrmann>

Status:

VERIFIED FIXED

QA Contact:

Severity:

enhancement

Priority:

Version:

1.4

Target Milestone:

0.7 M4

Hardware:

OS:

Linux

Whiteboard:

trac

Attachments:

Description	Flags
OTJLD additions	none
implementation	none

Description Stephan Herrmann

2010-06-08 15:56:19 EDT

(originally from http://trac.objectteams.org/ot/ticket/113)

In test 9.2.1-otjld-has-role-method-5c2, when defining the method binding in super-role R, the compiler reports:

  Callin mapping not allowed here, because lifting to role Team921hrm5c2.R is
  not possible due to a reported binding ambiguity (OTJLD 4.1(b)).

It should be checked whether this restriction can be removed. The method binding would have to be propagated down to all non-ambiguous sub-roles, so that the effect would be the same as what is currently written in the mentioned test.

-----

today's analysis: just omitting the error would indeed lead to code that
throws a LiftingFailedException, because the callin wrapper tries to lift
to the super role, even if a sub-role exists.

Possible actions:

 - the lift method could be made smarter to include a cache lookup
   even if a binding ambiguity has been detected.

 - errors regarding OTJLD 2.3.4(b) could be made configurable to admit
   the case where lifting is indeed decided by an existing role instance.
   This issue should be documented in 2.3.4(a,b) and 4.1(b)

Comment 1 Stephan Herrmann

2010-06-08 17:40:23 EDT

Created attachment 171473 [details]
OTJLD additions

These additions to the OTJLD define how the error message in question
can be configured/suppressed (using token "def-bind-ambiguity").

2.3.4(b) talks about the root error, 4.1(b) about how this can be
leveraged to define callin bindings even in an "unliftable" role.

Comment 2 Stephan Herrmann

2010-06-08 17:47:09 EDT

Created attachment 171474 [details]
implementation

This patch implements:
 - best effort lifting: even for ambiguous roles still check the cache
 - always generate callin wrappers, even if role has binding ambiguity
 - new configurable irritant DefiniteBindingAmbiguity
   (deliberately no UI-configurability - should always be individually checked)

Corresponding tests can be found in test73M_ambiguousBinding1() and
test73M_ambiguousBinding2(), which indeed test for both corner cases
mentioned in OTJLD 2.3.4(b).

Comment 3 Stephan Herrmann

2010-06-08 17:49:39 EDT

Implementation has been committed as r440.

Comment 4 Stephan Herrmann

2010-06-08 17:59:01 EDT

Two small fups have been committed in r442,r443.

Comment 5 Stephan Herrmann

2010-06-11 20:02:08 EDT

Verified for M4 using build 201006111053.