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6470 :: More fuzz testing

• neo (orginal) [2020-06-22T21:37:42+02:00] view original

  Follows an edge case, an unexpected behaviour or a programmer's bug?

  let sp = ' '
  let seq1 = @[1, 3, 5, 7]
  
  proc printSeq(s: seq, nprinted: int = -1) :string =
    var nprinted = if nprinted == -1: s.len else: min(nprinted, s.len)
    for i in 0 ..< nprinted:
      write(stdout, s[i], sp)
  
  write(stdout, "print first", printSeq(seq1), "\L")
  
  echo "printSeq(seq1, 2)", printSeq(seq1, 2)
  Run

  ouputs

  
  1 3 5 7 print first
  1 3 printSeq(seq1 ,2)
  Run

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• SolitudeSF (orginal) [2020-06-22T23:07:27+02:00] view original

  what's the bug?

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• neo (orginal) [2020-06-22T23:18:37+02:00] view original

  I would expect

  
  print first 1 3 5 7
  printSeq(seq1 ,2) 1 3
  Run

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• quetzalb (orginal) [2020-06-22T23:30:45+02:00] view original

  printSeq is writing to stdout itself before returning a default value empty string.

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• neo (orginal) [2020-06-23T15:12:32+02:00] view original

  I am still trying to figure out the logic

  let sp = ' '
  let seq1 = @[1, 3, 5, 7]
  
  proc printSeq(s: seq, nprinted: int = -1) :string =
    var nprinted = if nprinted == -1: s.len else: min(nprinted, s.len)
    for i in 0 ..< nprinted:
      write(stdout, s[i], sp)
  
  write(stdout, "print first", printSeq(seq1), "\L")
  write(stdout, printSeq(seq1), "print first", "\L")
  
  write(stdout, "print first ")
  write(stdout, printSeq(seq1), "\L")
  Run

  
  1 3 5 7 print first
  1 3 5 7 print first
  print first 1 3 5 7
  Run

  Why would "print first" not be streamed to stdout first?

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• Araq (orginal) [2020-06-23T15:28:08+02:00] view original

  Because write collects all the arguments in an array? See https://nim-lang.org/docs/io.html#write%2CFile%2Cvarargs%5Bstring%2C%5D

  Reading the docs can beat "fuzzing".

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