Clojure

PersistentList$EmptyList and empty LazySeq still returns old value for hasheq

Details

  • Type: Defect Defect
  • Status: Closed Closed
  • Priority: Blocker Blocker
  • Resolution: Completed
  • Affects Version/s: Release 1.6
  • Fix Version/s: Release 1.6
  • Component/s: None
  • Labels:
    None
  • Patch:
    Code and Test
  • Approval:
    Ok

Description

After late Jan 2014 changes to hash functions, PersistentList$EmptyList and (lazy-seq) were left behind:

user=> (= '() (lazy-seq) [])
true
user=> (map hash ['() (lazy-seq) []])
(1 1 -2017569654)
user=> (map class ['() (lazy-seq) []])
(clojure.lang.PersistentList$EmptyList clojure.lang.LazySeq clojure.lang.PersistentVector)

PersistentQueue/EMPTY was updated, so should not need any change.

Solution: Update LazySeq.hasheq() and make EmptyList implement IHashEq. EmptyList now creates a static constant for the hash value of an empty ordered collection and returns the constant for hasheq. An alternative would be to have Murmur3 have this constant instead.

Patch: clj-1335-v2.patch
Depends on: CLJ-1338, CLJ-1339, CLJ-1331 (must be applied first)

Patch:

  1. clj-1335-v1.diff
    30/Jan/14 6:33 PM
    6 kB
    Andy Fingerhut
  2. clj-1335-v2.patch
    04/Feb/14 5:13 PM
    5 kB
    Alex Miller

Activity

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Andy Fingerhut added a comment -

Patch clj-1335-v1.diff adds tests that assume the patch clj-1331-v1.diff on ticket CLJ-1331 have already been committed. If it is desired to combine these into one patch, or commit this one without that one, I can eliminate that dependency.

Makes PersistentList$EmptyList implement IHashEq interface with a straightforward implementation of hasheq(), comments out empty LazySeq special case check that caused it to return old hash value, and fixes a NullPointerException for primitive vectors discovered by the new tests added.

Show
Andy Fingerhut added a comment - Patch clj-1335-v1.diff adds tests that assume the patch clj-1331-v1.diff on ticket CLJ-1331 have already been committed. If it is desired to combine these into one patch, or commit this one without that one, I can eliminate that dependency. Makes PersistentList$EmptyList implement IHashEq interface with a straightforward implementation of hasheq(), comments out empty LazySeq special case check that caused it to return old hash value, and fixes a NullPointerException for primitive vectors discovered by the new tests added.

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Dates

  • Created:
    Updated:
    Resolved: