Blocker Description
My Jenkins found two reproducing seeds on branch_6x - these look different, but the failures happened on consecutive nightly runs:
Checking out Revision 535bf59a3b239f5c7bcd8c00f3e452c9b5e9b539 (refs/remotes/origin/branch_6x)
[...]
[junit4] Suite: org.apache.lucene.index.TestIndexSorting
[junit4] 2> ??? 18, 2016 9:50:39 AM com.carrotsearch.randomizedtesting.RandomizedRunner$QueueUncaughtExceptionsHandler uncaughtException
[junit4] 2> WARNING: Uncaught exception in thread: Thread[Lucene Merge Thread #0,5,TGRP-TestIndexSorting]
[junit4] 2> org.apache.lucene.index.MergePolicy$MergeException: java.lang.AssertionError: nextValue=4594289799775307848 vs previous=4606302611760746829
[junit4] 2> at __randomizedtesting.SeedInfo.seed([5F8898DCABBFD056]:0)
[junit4] 2> at org.apache.lucene.index.ConcurrentMergeScheduler.handleMergeException(ConcurrentMergeScheduler.java:668)
[junit4] 2> at org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:648)
[junit4] 2> Caused by: java.lang.AssertionError: nextValue=4594289799775307848 vs previous=4606302611760746829
[junit4] 2> at org.apache.lucene.codecs.asserting.AssertingDocValuesFormat$AssertingDocValuesConsumer.addSortedNumericField(AssertingDocValuesFormat.java:152)
[junit4] 2> at org.apache.lucene.codecs.DocValuesConsumer.mergeSortedNumericField(DocValuesConsumer.java:470)
[junit4] 2> at org.apache.lucene.codecs.DocValuesConsumer.merge(DocValuesConsumer.java:243)
[junit4] 2> at org.apache.lucene.codecs.perfield.PerFieldDocValuesFormat$FieldsWriter.merge(PerFieldDocValuesFormat.java:153)
[junit4] 2> at org.apache.lucene.index.SegmentMerger.mergeDocValues(SegmentMerger.java:167)
[junit4] 2> at org.apache.lucene.index.SegmentMerger.merge(SegmentMerger.java:111)
[junit4] 2> at org.apache.lucene.index.IndexWriter.mergeMiddle(IndexWriter.java:4320)
[junit4] 2> at org.apache.lucene.index.IndexWriter.merge(IndexWriter.java:3897)
[junit4] 2> at org.apache.lucene.index.ConcurrentMergeScheduler.doMerge(ConcurrentMergeScheduler.java:588)
[junit4] 2> at org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:626)
[junit4] 2>
[junit4] 2> NOTE: download the large Jenkins line-docs file by running 'ant get-jenkins-line-docs' in the lucene directory.
[junit4] 2> NOTE: reproduce with: ant test -Dtestcase=TestIndexSorting -Dtests.method=testRandom3 -Dtests.seed=5F8898DCABBFD056 -Dtests.multiplier=2 -Dtests.nightly=true -Dtests.slow=true -Dtests.linedocsfile=/home/jenkins/lucene-data/enwiki.random.lines.txt -Dtests.locale=he -Dtests.timezone=Canada/Central -Dtests.asserts=true -Dtests.file.encoding=ISO-8859-1
[junit4] ERROR 14.9s J5 | TestIndexSorting.testRandom3 <<<
[junit4] > Throwable #1: org.apache.lucene.store.AlreadyClosedException: this IndexWriter is closed
[junit4] > at org.apache.lucene.index.IndexWriter.ensureOpen(IndexWriter.java:748)
[junit4] > at org.apache.lucene.index.IndexWriter.ensureOpen(IndexWriter.java:762)
[junit4] > at org.apache.lucene.index.IndexWriter.updateDocument(IndexWriter.java:1566)
[junit4] > at org.apache.lucene.index.IndexWriter.addDocument(IndexWriter.java:1315)
[junit4] > at org.apache.lucene.index.TestIndexSorting.testRandom3(TestIndexSorting.java:2019)
[junit4] > at java.lang.Thread.run(Thread.java:745)
[junit4] > Caused by: java.lang.AssertionError: nextValue=4594289799775307848 vs previous=4606302611760746829
[junit4] > at org.apache.lucene.codecs.asserting.AssertingDocValuesFormat$AssertingDocValuesConsumer.addSortedNumericField(AssertingDocValuesFormat.java:152)
[junit4] > at org.apache.lucene.codecs.DocValuesConsumer.mergeSortedNumericField(DocValuesConsumer.java:470)
[junit4] > at org.apache.lucene.codecs.DocValuesConsumer.merge(DocValuesConsumer.java:243)
[junit4] > at org.apache.lucene.codecs.perfield.PerFieldDocValuesFormat$FieldsWriter.merge(PerFieldDocValuesFormat.java:153)
[junit4] > at org.apache.lucene.index.SegmentMerger.mergeDocValues(SegmentMerger.java:167)
[junit4] > at org.apache.lucene.index.SegmentMerger.merge(SegmentMerger.java:111)
[junit4] > at org.apache.lucene.index.IndexWriter.mergeMiddle(IndexWriter.java:4320)
[junit4] > at org.apache.lucene.index.IndexWriter.merge(IndexWriter.java:3897)
[junit4] > at org.apache.lucene.index.ConcurrentMergeScheduler.doMerge(ConcurrentMergeScheduler.java:588)
[junit4] > at org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:626)Throwable #2: com.carrotsearch.randomizedtesting.UncaughtExceptionError: Captured an uncaught exception in thread: Thread[id=1115, name=Lucene Merge Thread #0, state=RUNNABLE, group=TGRP-TestIndexSorting]
[junit4] > Caused by: org.apache.lucene.index.MergePolicy$MergeException: java.lang.AssertionError: nextValue=4594289799775307848 vs previous=4606302611760746829
[junit4] > at __randomizedtesting.SeedInfo.seed([5F8898DCABBFD056]:0)
[junit4] > at org.apache.lucene.index.ConcurrentMergeScheduler.handleMergeException(ConcurrentMergeScheduler.java:668)
[junit4] > at org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:648)
[junit4] > Caused by: java.lang.AssertionError: nextValue=4594289799775307848 vs previous=4606302611760746829
[junit4] > at org.apache.lucene.codecs.asserting.AssertingDocValuesFormat$AssertingDocValuesConsumer.addSortedNumericField(AssertingDocValuesFormat.java:152)
[junit4] > at org.apache.lucene.codecs.DocValuesConsumer.mergeSortedNumericField(DocValuesConsumer.java:470)
[junit4] > at org.apache.lucene.codecs.DocValuesConsumer.merge(DocValuesConsumer.java:243)
[junit4] > at org.apache.lucene.codecs.perfield.PerFieldDocValuesFormat$FieldsWriter.merge(PerFieldDocValuesFormat.java:153)
[junit4] > at org.apache.lucene.index.SegmentMerger.mergeDocValues(SegmentMerger.java:167)
[junit4] > at org.apache.lucene.index.SegmentMerger.merge(SegmentMerger.java:111)
[junit4] > at org.apache.lucene.index.IndexWriter.mergeMiddle(IndexWriter.java:4320)
[junit4] > at org.apache.lucene.index.IndexWriter.merge(IndexWriter.java:3897)
[junit4] > at org.apache.lucene.index.ConcurrentMergeScheduler.doMerge(ConcurrentMergeScheduler.java:588)
[junit4] > at org.apache.lucene.index.ConcurrentMergeScheduler$MergeThread.run(ConcurrentMergeScheduler.java:626)
[junit4] 2> NOTE: leaving temporary files on disk at: /var/lib/jenkins/jobs/Lucene-Solr-Nightly-6.x/workspace/lucene/build/core/test/J5/temp/lucene.index.TestIndexSorting_5F8898DCABBFD056-001
[junit4] 2> NOTE: test params are: codec=Asserting(Lucene62): {docs=PostingsFormat(name=Direct), norms=PostingsFormat(name=Direct), positions=PostingsFormat(name=Memory doPackFST= false), id=PostingsFormat(name=Direct), term_vectors=PostingsFormat(name=LuceneFixedGap)}, docValues:{multi_valued_long=DocValuesFormat(name=Lucene54), double=DocValuesFormat(name=Direct), foo=DocValuesFormat(name=Lucene54), numeric=DocValuesFormat(name=Direct), positions=DocValuesFormat(name=Lucene54), multi_valued_numeric=DocValuesFormat(name=Asserting), float=DocValuesFormat(name=Memory), int=DocValuesFormat(name=Asserting), long=DocValuesFormat(name=Memory), points=DocValuesFormat(name=Asserting), sorted=DocValuesFormat(name=Direct), multi_valued_double=DocValuesFormat(name=Asserting), docs=DocValuesFormat(name=Asserting), multi_valued_string=DocValuesFormat(name=Asserting), norms=DocValuesFormat(name=Asserting), bytes=DocValuesFormat(name=Asserting), binary=DocValuesFormat(name=Direct), id=DocValuesFormat(name=Asserting), multi_valued_int=DocValuesFormat(name=Direct), multi_valued_bytes=DocValuesFormat(name=Direct), multi_valued_float=DocValuesFormat(name=Memory), term_vectors=DocValuesFormat(name=Direct)}, maxPointsInLeafNode=1312, maxMBSortInHeap=5.376962888308618, sim=RandomSimilarity(queryNorm=true,coord=yes): {positions=DFR I(ne)3(800.0), id=IB LL-L3(800.0), term_vectors=DFR I(ne)B3(800.0)}, locale=he, timezone=Canada/Central
[junit4] 2> NOTE: Linux 4.1.0-custom2-amd64 amd64/Oracle Corporation 1.8.0_77 (64-bit)/cpus=16,threads=1,free=132261744,total=508559360
[junit4] 2> NOTE: All tests run in this JVM: [TestFixedBitSet, TestSearchAfter, TestMinShouldMatch2, TestStopFilter, TestMmapDirectory, TestAutomaton, TestTransactions, TestMultiLevelSkipList, TestForUtil, TestFieldType, TestIntBlockPool, TestNumericRangeQuery64, TestBoolean2, Test2BPositions, TestDemo, TestSpanBoostQuery, TestSpanMultiTermQueryWrapper, TestCharsRefBuilder, TestIOUtils, TestAllFilesHaveChecksumFooter, TestMaxTermFrequency, TestConjunctionDISI, TestIndexWriterMerging, TestPackedInts, TestLucene50StoredFieldsFormat, TestGeoEncodingUtils, TestGeoUtils, Test2BPoints, Test2BSortedDocValuesFixedSorted, TestDocValues, TestExceedMaxTermLength, TestExitableDirectoryReader, TestFilterDirectoryReader, TestIndexSorting]
[junit4] Completed [345/441 (1!)] on J5 in 39.46s, 43 tests, 1 error <<< FAILURES!
Checking out Revision 500f6c7875be31c34ca68c58f850b7e64fd049a9 (refs/remotes/origin/branch_6x)
[...]
[junit4] Suite: org.apache.lucene.index.TestIndexSorting
[junit4] 2> NOTE: download the large Jenkins line-docs file by running 'ant get-jenkins-line-docs' in the lucene directory.
[junit4] 2> NOTE: reproduce with: ant test -Dtestcase=TestIndexSorting -Dtests.method=testRandom3 -Dtests.seed=5D1E2D97B0777D5C -Dtests.multiplier=2 -Dtests.nightly=true -Dtests.slow=true -Dtests.linedocsfile=/home/jenkins/lucene-data/enwiki.random.lines.txt -Dtests.locale=fi-FI -Dtests.timezone=America/Tegucigalpa -Dtests.asserts=true -Dtests.file.encoding=UTF-8
[junit4] ERROR 245s J3 | TestIndexSorting.testRandom3 <<<
[junit4] > Throwable #1: java.lang.RuntimeException: segment has indexSort=<float: "float">! missingValue=0.38226813,<sortedset: "multi_valued_bytes">! selector=MIN,<int: "id"> but docID=75 sorts after docID=76
[junit4] > at __randomizedtesting.SeedInfo.seed([5D1E2D97B0777D5C:FFC6634DD485545A]:0)
[junit4] > at org.apache.lucene.index.CheckIndex.testSort(CheckIndex.java:876)
[junit4] > at org.apache.lucene.index.CheckIndex.checkIndex(CheckIndex.java:756)
[junit4] > at org.apache.lucene.util.TestUtil.checkIndex(TestUtil.java:300)
[junit4] > at org.apache.lucene.store.MockDirectoryWrapper.close(MockDirectoryWrapper.java:865)
[junit4] > at org.apache.lucene.util.IOUtils.close(IOUtils.java:89)
[junit4] > at org.apache.lucene.util.IOUtils.close(IOUtils.java:76)
[junit4] > at org.apache.lucene.index.TestIndexSorting.testRandom3(TestIndexSorting.java:2087)
[junit4] > at java.lang.Thread.run(Thread.java:745)
[junit4] 2> NOTE: leaving temporary files on disk at: /var/lib/jenkins/jobs/Lucene-Solr-Nightly-6.x/workspace/lucene/build/core/test/J3/temp/lucene.index.TestIndexSorting_5D1E2D97B0777D5C-001
[junit4] 2> NOTE: test params are: codec=CheapBastard, sim=RandomSimilarity(queryNorm=true,coord=no): {positions=DFR I(F)BZ(0.3), id=IB SPL-DZ(0.3), term_vectors=DFR I(ne)3(800.0)}, locale=fi-FI, timezone=America/Tegucigalpa
[junit4] 2> NOTE: Linux 4.1.0-custom2-amd64 amd64/Oracle Corporation 1.8.0_77 (64-bit)/cpus=16,threads=1,free=252779544,total=525336576
[junit4] 2> NOTE: All tests run in this JVM: [TestBooleanRewrites, TestSearchForDuplicates, TestSwappedIndexFiles, TestClassicSimilarity, TestNeverDelete, TestAllFilesCheckIndexHeader, TestBooleanScorer, TestPayloads, TestDelegatingAnalyzerWrapper, TestWeakIdentityMap, TestRollingBuffer, TestParallelCompositeReader, TestExitableDirectoryReader, TestCollectionUtil, TestLegacyNumericUtils, TestBagOfPostings, TestNot, TestPhrasePrefixQuery, TestSimpleExplanationsWithFillerDocs, TestPriorityQueue, TestBlockPostingsFormat2, TestIntroSorter, FiniteStringsIteratorTest, TestIndexWriterReader, TestNumericRangeQuery64, TestDeletionPolicy, TestBooleanOr, TestSloppyPhraseQuery, TestNRTThreads, TestPolygon, TestPolygon2D, TestDocValues, TestFilterDirectoryReader, TestIndexSorting]
[junit4] Completed [431/441 (1!)] on J3 in 263.65s, 43 tests, 1 error <<< FAILURES!