On 7 juin 2013, at 11:19, Pharo Issue Tracker wrote:

A FogBugz case was edited by Stephane Ducasse.

Case ID:      10840
Title:        WeakSet>>#size utterly broken
Status:       Resolved (Fix Review Needed)
Category:     Bug
Project:      Collection
Area:         Misc
Priority:     3 - Must Fix
Milestone:    Pharo3.0: 30/03/2014
Assigned To: Camille Teruel

URL:          https://pharo.fogbugz.com/f/cases/10840

Last message:
Please can you send a mail to the mailing-list so that we all discuss this problems.

Hello everyone,

WeakSet>>#size is broken as demonstrated by the following snippet:

set := WeakSet new.

set add: Object new.

Smalltalk garbageCollect.

set size. "answers 1 instead of 0"

That is because a WeakSet has no mean to know when its items get garbage collected, and thus the tally cannot be updated.

So we need to override #size in Weak, I propose:

size

| counter |

counter := 0.

self do: [ :e | counter := counter + 1 ].

^ counter

But that it rather inefficient for such a simple query.

Any proposition?

The bug entry is: https://pharo.fogbugz.com/f/cases/10840

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