CharArraySet.contains(char[] text, int off, int len) does not work

• Key: LUCENE-1163
• Type: Bug
• Status: Closed
• Resolution: Fixed
• Priority: Major
• Assignee: Michael McCandless
• Reporter: Thomas Peuss
• Affects Version/s: 2.3
• Fix Version/s: 2.4

Description

I try to use the CharArraySet for a filter I am writing. I heavily use char-arrays in my code to speed up things. I stumbled upon a bug in CharArraySet while doing that.

The method public boolean contains(char[] text, int off, int len) seems not to work.

When I do

if (set.contains(buffer,offset,length) {
  ...
}

my code fails.

But when I do

if (set.contains(new String(buffer,offset,length)) {
   ...
}

everything works as expected.

Both variants should behave the same. I attach a small piece of code to show the problem.

Comments

A simple piece of code that shows the problem.

[Michael McCandless]

Indeed it's really a bug – thank you for finding this & reporting it Thomas!

We were ignoring the offset when computing the hash code internally.

Lucene always passes '0' for this offset (only used in StopFilter currently) so it wasn't hitting any existing Lucene test cases.

I turned your example into a test case in the attached patch. I will commit shortly.

[Thomas Peuss]

Thanks for the quick response. I can confirm that the patch fixes the problem.

[Michael McCandless]

Super, thanks Thomas! I just committed this.

[Michael McCandless]

I'll port this one to 2.3.1 as well.

[Michael McCandless]

Backported to 2.3