Thanks for reporting this! Yeah, Git is there for convenience, JIRAs are how we
track code changes, the "usual" method of drawing attention to a code problem
is to attach a patch to a JIRA.

I noticed that the "How To Contribute" page really doesn't mention this, I'll see
if I can update it.

Thanks for both noticing the original problem and your persistence bringing it
to our attention!

Is there a small test case that exposes this bug? I'd like to fix this, and it certainly looks like a silly bug, but I don't fully understand GermStemmer so it would be nice to shine a light on the bug first with a test case.

Hi Michael,

I tried to write a small test case and realized that there is no input that leads to a wrong token.
substCount is only used to decide how large the original input was, because some suffixes are only stripped if the token has a minimum length.

if ( ( buffer.length() + substCount > 5 ) &&
      buffer.substring( buffer.length() - 2, buffer.length() ).equals( "nd" ) )
    {
      buffer.delete( buffer.length() - 2, buffer.length() );
    }

However, every substitution leaves at least one character. For the bug to take effect, there has to be a substitution before the one that sets substCount to 2 (instead of incrementing it by 2).
So we have

• 2 characters that where left by the (at least 2) substitutions
• the suffix "nd"
• substCount, which was set to 2
  That sums up to 6 , which is greater than 5

The other conditions that check on substCount work the same, except they check for greater than 4.

Therefore, there is no token that triggers any wrong behaviour.

Still, I think the typo should be fixed, because it might be copied to a place where it has an effect.

OK, thanks for exploring for a possible test case Christoph Kaser, I'll commit your fix as is!

Commit 1687950 from Michael McCandless in branch 'dev/trunk'
[ https://svn.apache.org/r1687950 ]

LUCENE-6586: fix typo causing possible wrong value for substCount

Commit 1687951 from Michael McCandless in branch 'dev/branches/branch_5x'
[ https://svn.apache.org/r1687951 ]

LUCENE-6586: fix typo causing possible wrong value for substCount

Thanks Christoph Kaser!

Bulk close for 5.3.0 release