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  1. Core Server
  2. SERVER-18341

Matcher returns false positives in comparison predicates with MinKey/MaxKey

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    • Fully Compatible
    • ALL
    • v4.0, v3.6
    • Query 2018-07-02, Query 2018-07-16

    Description

      For any field "a", the matcher falsely considers all documents (with the exception of {a: MaxKey} and {a: MinKey}) as matching the following predicates:

      {a: {$gt: MaxKey}}
      {a: {$gte: MaxKey}}
      {a: {$lt: MinKey}}
      {a: {$lte: MinKey}}
      

      Reproduce with the following shell snippet. The assertion on the last line fails.

      db.foo.drop();
      db.foo.insert({a: 1});
      db.foo.ensureIndex({a: 1});
      assert.eq(0, db.foo.find({a: {$gt: MaxKey}}).itcount()); // Passes as expected.
      db.foo.dropIndexes();
      assert.eq(0, db.foo.find({a: {$gt: MaxKey}}).itcount()); // Fails: itcount() returns 1.
      

      This is a regression introduced in 2.3.0 by e1085e54 (SERVER-3104). Affects all versions released since.

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              minji.kim Minji Kim
              rassi J Rassi
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                Updated:
                Resolved: