Boo

Automatic interface stubbing can create method conflicts

Details

  • Type: Bug Bug
  • Status: Open Open
  • Priority: Major Major
  • Resolution: Unresolved
  • Affects Version/s: 0.8.2
  • Fix Version/s: 0.9.5
  • Component/s: Compiler
  • Labels:
    None
  • Number of attachments :
    1

Description

When the compiler automatically adds stubs for unimplemented interface methods, they can conflict with other defined or stubbed methods which differ by return type only.

Failing testcase:

import System.Collections.Generic

public class StubMePlease(IEnumerable of int):
    pass

The compiler will create a stub for "GetEnumerator() as IEnumerator" as defined by IEnumerable, and for "GetEnumerator() as IEnumerator of int" as defined by IEnumerable of int. The two methods, differing only by return type, create a conflict.

Proposed solution: use explicit interface implementation for interface stubs. This will work well since the stubs are empty anyway, so there's no use in listing them as public members of the stubbed class.

Issue Links

relates to

Improvement - An improvement or enhancement to an existing feature or task. BOO-789 Compiler should warn but automatically create stubs for non implemented interfaces methods

  • Major - Major loss of function.
  • Resolved - A resolution has been taken, and it is awaiting verification by reporter. From here issues are either reopened, or are closed.

Activity

Ascending order - Click to sort in descending order
Hide
Permalink
Greg Nagel added a comment -

Created a patch for the issue, thought it breaks several test cases (which rely on the old behavior).

These are the tests that fail:

tests\testcases\warnings\BCW0011-6.boo
tests\testcases\semantics\interfaces-0.boo
tests\testcases\semantics\interfaces-2.boo
tests\testcases\integration/types\interfaces-15.boo
tests\testcases\integration/types\interfaces-16.boo
tests\testcases\integration/types\interfaces-18.boo

Any code affected by this was getting a warning anyway, so it's not really a breaking change.

Show
Greg Nagel added a comment - Created a patch for the issue, thought it breaks several test cases (which rely on the old behavior). These are the tests that fail: tests\testcases\warnings\BCW0011-6.boo tests\testcases\semantics\interfaces-0.boo tests\testcases\semantics\interfaces-2.boo tests\testcases\integration/types\interfaces-15.boo tests\testcases\integration/types\interfaces-16.boo tests\testcases\integration/types\interfaces-18.boo Any code affected by this was getting a warning anyway, so it's not really a breaking change.
Hide
Permalink
Cedric Vivier added a comment - - edited

Slightly different solution I plan to implement: use explicit interface implementation for interface stubs only when there is a conflict (and report these stubs as such).

Always using explicit interface implementation (as in the patch) would reduce the value of automatic stubbing for prototyping since we couldn't anymore implement (and compile) a class before another not fully implemented class without using casts etc to be able to call the explicit implementation.

Show
Cedric Vivier added a comment - - edited Slightly different solution I plan to implement: use explicit interface implementation for interface stubs only when there is a conflict (and report these stubs as such). Always using explicit interface implementation (as in the patch) would reduce the value of automatic stubbing for prototyping since we couldn't anymore implement (and compile) a class before another not fully implemented class without using casts etc to be able to call the explicit implementation.

People

  • Assignee:
    Cedric Vivier
    Reporter:
    Avishay Lavie
Vote (0)
Watch (0)

Dates

  • Created:
    Updated: