Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-38851

Replace assert.close() with separate functions for integer and floating point closeness

    XMLWordPrintable

    Details

    • Operating System:
      ALL

      Description

      assert.close() is used in our code both to compare for equality floating point numbers to a degree of precision and to integer values, evaluating only the X most significant digits. We should instead have separate functions for the 2. The current implementation can lead to surprising results when looking at it from only one use case:

      > 
      > assert.close(1, 2, '', 4)
      2019-01-04T16:26:47.030-0500 E QUERY    [js] Error: 1 is not equal to 2 within 4 places, absolute error: 1, relative error: 0.5 :
      doassert@src/mongo/shell/assert.js:20:14
      assert.close@src/mongo/shell/assert.js:903:9
      @(shell):1:1
      > 
      > // Result may be surprising to someone looking for a floating point precision check.
      > assert.close(100001, 100002, '', 4)
      > 
      > assert.close(0.01, 0.02, '', 4)
      2019-01-04T16:27:11.086-0500 E QUERY    [js] Error: 0.01 is not equal to 0.02 within 4 places, absolute error: 0.01, relative error: 0.5 :
      doassert@src/mongo/shell/assert.js:20:14
      assert.close@src/mongo/shell/assert.js:903:9
      @(shell):1:1
      > 
      > assert.close(0.000001, 0.000002, '', 4)
      > 
      > // This fails a floating point precision check, but does not assert.
      > assert.close(2000000.1, 2000000.2, '', 4)
      > 
      

        Attachments

          Issue Links

            Activity

              People

              • Votes:
                0 Vote for this issue
                Watchers:
                3 Start watching this issue

                Dates

                • Created:
                  Updated: