Shrinking is Insanely Slow for write_read #596

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1. Bodigrim commented on May 23, 2024

   

   Bodigrim

   on May 23, 2024

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   I imagine at the very least we don't want to shrink first three arguments of

     propTest :: TextEncoding -> Gen IO.BufferMode -> IO.NewlineMode -> c -> Property
2. BebeSparkelSparkel commented on May 25, 2024

   

   BebeSparkelSparkel

   on May 25, 2024

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   The encoding is not shrunk. I have wrapped the other two with NoShrink but without much improvement. See #597
3. Bodigrim commented on May 25, 2024

   

   Bodigrim

   on May 25, 2024

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         input-output
           t_write_read
             UTF-8
               NoBuffering:                                      OK (0.80s)
                 +++ OK, passed 100 tests; 39 discarded.
               LineBuffering:                                    OK (0.10s)
                 +++ OK, passed 100 tests; 27 discarded.
               BlockBuffering:                                   FAIL (1448.46s)
                 *** Failed! (after 72 tests and 2007 shrinks):
                 Exception:
                   Assertion failed
                   CallStack (from HasCallStack):
                     assert, called at src/Data/Text/IO.hs:249:35 in text-2.1.1-inplace:Data.Text.IO
                 NewlineMode {inputNL = LF, outputNL = LF}
                 ["aaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaa","aaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","a","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaa","aa","aaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaa","aa","","aaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"]
                 BlockBuffering (Just 4)
                 Use --quickcheck-replay=934323 to reproduce.
                 Use -p '/t_write_read.UTF-8.BlockBuffering/' to rerun this test only.
   

   2007 shrinks is a high number, but on the other hand why did they take 1448 seconds? That's 0.7 seconds per test, which sounds a lot, given that the test data does not seem to be that huge.
4. BebeSparkelSparkel commented on May 25, 2024

   

   BebeSparkelSparkel

   on May 25, 2024

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   I think many more tests are run than 2007. If you look at numShrinkTries, so I think 2007 represents numShrinks but the number of tries is not shown.
5. BebeSparkelSparkel commented on May 25, 2024

   

   BebeSparkelSparkel

   on May 25, 2024

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   I imagine there are so many shrinks tried because there are many variables to shrink

   • length of list
   • length of each text
   • every character

   I think if the character variable is removed this would perform much better. Either, do not modify the characters or set them all to 'a'.
6. Bodigrim commented on May 25, 2024

   

   Bodigrim

   on May 25, 2024

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   Dunno, maybe lumping NoShrink is the simplest solution. I'm not too keen to have a custom wrapper with instance Arbitrary here...
7. BebeSparkelSparkel commented on May 26, 2024

   

   BebeSparkelSparkel

   on May 26, 2024

   Last edited by BebeSparkelSparkel

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   I just added NoShrink to quickcheck and it has been pulled nick8325/quickcheck#408. We could up the version of quickcheck and use it.