Immutable set size incorrect after filter

[scabug]

Calling filter on an immutable set with 5 elements causes it to report the wrong size initially. Iteration over the set seems to fix the problem. Here's a simple JUnit4 test case:

package test;

import org.junit.Test
import org.junit.Assert._

class SetTest {

@Test
def testSetSize = {
  val set = Set("0", "1", "2", "3", "4")
  assertEquals(5, set.size)
  
  val filteredSet = set filter (_ equals "0")
  assertEquals(5, set.size)
  assertEquals(1, filteredSet.size)
}

}

The error is the following:

testSetSize(test.SetTest) Time elapsed: 0.066 sec <<< FAILURE!
java.lang.AssertionError: expected:<5> but was:<9>
at org.junit.Assert.fail(Assert.java:74)
at org.junit.Assert.failNotEquals(Assert.java:448)
at org.junit.Assert.assertEquals(Assert.java:102)
at org.junit.Assert.assertEquals(Assert.java:117)
at test.SetTest.testSetSize(SetTest.scala:14)

Reproduced with Scala 2.6.1 and JDK 6 update 4.

This is a very hard to debug issue, so I think it should be given high priority. Thanks.

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-454?orig=1
Reporter: @ijuma
Attachments:

• SetTest.scala (created on Feb 7, 2008 6:17:25 PM UTC, 329 bytes)

[scabug]

@ijuma said:
JUnit 4 test that shows the problem

[scabug]

@ijuma said:
I've attached a file with the test because the lines got a bit messed up in the in-line version.

[scabug]

@ijuma said:
This is the same issue as ticket #768. See comment #5 for more details.

[scabug]

@ijuma said:
Fixed in r14711 and r14727.

[scabug]

@odersky said:
Milestone 2.7.1 deleted