[LUCENE-2635] BQ provides an explanation on a non-match

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.1, 4.0-ALPHA
• Component/s: core/search
• Lucene Fields: New
• Assignee: Michael McCandless
• Reporter: Michael McCandless
• Created: 08/Sep/10 10:21
• Updated: 28/Aug/22 12:32
• Resolved: 08/Sep/10 10:35

Description

Plug in seed -6336594106867842617L into TestExplanations then run TestSimpleExplanationsOfNonMatches and you'll hit this:

    [junit] Testsuite: org.apache.lucene.search.TestSimpleExplanationsOfNonMatches
    [junit] Testcase: testBQ2(org.apache.lucene.search.TestSimpleExplanationsOfNonMatches):	FAILED
    [junit] Explanation of [[+yy +w3]] for #0 doesn't indicate non-match: 0.08778467 = (MATCH) product of:
    [junit]   0.17556934 = (MATCH) sum of:
    [junit]     0.17556934 = (MATCH) weight(field:w3 in 0), product of:
    [junit]       0.5165708 = queryWeight(field:w3), product of:
    [junit]         0.7768564 = idf(docFreq=4, maxDocs=4)
    [junit]         0.6649502 = queryNorm
    [junit]       0.33987468 = (MATCH) fieldWeight(field:w3 in 0), product of:
    [junit]         1.0 = tf(termFreq(field:w3)=1)
    [junit]         0.7768564 = idf(docFreq=4, maxDocs=4)
    [junit]         0.4375 = fieldNorm(field=field, doc=0)
    [junit]   0.5 = coord(1/2)
    [junit]  expected:<0.0> but was:<0.08778467>
    [junit] junit.framework.AssertionFailedError: Explanation of [[+yy +w3]] for #0 doesn't indicate non-match: 0.08778467 = (MATCH) product of:
    [junit]   0.17556934 = (MATCH) sum of:
    [junit]     0.17556934 = (MATCH) weight(field:w3 in 0), product of:
    [junit]       0.5165708 = queryWeight(field:w3), product of:
    [junit]         0.7768564 = idf(docFreq=4, maxDocs=4)
    [junit]         0.6649502 = queryNorm
    [junit]       0.33987468 = (MATCH) fieldWeight(field:w3 in 0), product of:
    [junit]         1.0 = tf(termFreq(field:w3)=1)
    [junit]         0.7768564 = idf(docFreq=4, maxDocs=4)
    [junit]         0.4375 = fieldNorm(field=field, doc=0)
    [junit]   0.5 = coord(1/2)
    [junit]  expected:<0.0> but was:<0.08778467>
    [junit] 	at org.apache.lucene.search.CheckHits.checkNoMatchExplanations(CheckHits.java:60)
    [junit] 	at org.apache.lucene.search.TestSimpleExplanationsOfNonMatches.qtest(TestSimpleExplanationsOfNonMatches.java:36)
    [junit] 	at org.apache.lucene.search.TestExplanations.qtest(TestExplanations.java:101)
    [junit] 	at org.apache.lucene.search.TestSimpleExplanations.testBQ2(TestSimpleExplanations.java:235)
    [junit] 	at org.apache.lucene.util.LuceneTestCase.runBare(LuceneTestCase.java:397)
    [junit] 	at org.apache.lucene.util.LuceneTestCase.run(LuceneTestCase.java:389)

The bug is real – BQ's explain method fails to properly enforce required clauses when the sub-scorer is null. Thank you random testing!