[Xapian-tickets] [Xapian] #724: Handle overflow of collection frequency

[Xapian]

#724: Handle overflow of collection frequency
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        Reporter:  olly           |      Owner:  olly
            Type:  defect         |     Status:  new
        Priority:  normal         |  Milestone:  1.4.x
       Component:  Backend-Glass  |    Version:  git master
        Severity:  normal         |   Keywords:
      Blocked By:                 |   Blocking:
Operating System:  All            |
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 Test case totaldoclen1 under chert was triggering undefined behaviour via
 signed integer overflow of the collection frequency deltas, and that was
 causing errors under ubsan.

 I've patched the testcase to avoid this, so it tests what it aims to, and
 the testsuite doesn't fail under ubsan.

 We ought to handle overflow of collection frequency better (hence this
 ticket) but in practice this isn't likely to happen until database get
 very large unless people deliberately set artificially high wdf (which is
 what the testcase was doing).

 Although glass wasn't triggering ubsan errors the same issue does apply to
 glass, so marking as Backend-Glass since glass is the default backend for
 1.4.x.

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Ticket URL: <https://trac.xapian.org/ticket/724>
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