test: Catch decimal.InvalidOperation from TestNodeCLI#send_cli #19632

decimal.InvalidOperation is a special case of a float parsing error, which presumably should be handled in the same way as a general parsing error, rather than blow up.

Alternatives include: logging the error, or re-raising with more information.

Example log output:

    File "/home/travis/build/bitcoin/bitcoin/ci/scratch/build/bitcoin-i686-pc-linux-gnu/test/functional/test_framework/test_framework.py", line 603, in sync_all
      self.sync_blocks(nodes)
    File "/home/travis/build/bitcoin/bitcoin/ci/scratch/build/bitcoin-i686-pc-linux-gnu/test/functional/test_framework/test_framework.py", line 568, in sync_blocks
      best_hash = [x.getbestblockhash() for x in rpc_connections]
    File "/home/travis/build/bitcoin/bitcoin/ci/scratch/build/bitcoin-i686-pc-linux-gnu/test/functional/test_framework/test_framework.py", line 568, in <listcomp>
      best_hash = [x.getbestblockhash() for x in rpc_connections]
    File "/home/travis/build/bitcoin/bitcoin/ci/scratch/build/bitcoin-i686-pc-linux-gnu/test/functional/test_framework/test_node.py", line 571, in __call__
      return self.cli.send_cli(self.command, *args, **kwargs)
    File "/home/travis/build/bitcoin/bitcoin/ci/scratch/build/bitcoin-i686-pc-linux-gnu/test/functional/test_framework/test_node.py", line 639, in send_cli
      return json.loads(cli_stdout, parse_float=decimal.Decimal)
    File "/usr/lib64/python3.6/json/__init__.py", line 367, in loads
      return cls(**kw).decode(s)
    File "/usr/lib64/python3.6/json/decoder.py", line 339, in decode
      obj, end = self.raw_decode(s, idx=_w(s, 0).end())
    File "/usr/lib64/python3.6/json/decoder.py", line 355, in raw_decode
      obj, end = self.scan_once(s, idx)
  decimal.InvalidOperation: [<class 'decimal.InvalidOperation'>]

See: https://travis-ci.org/github/bitcoin/bitcoin/jobs/713502326

Too bad the stdout isn't available. I presume it is something like "connection reset"?

ACK

ACK 82fc4017b774aaff8799c2b6e8ba5370d94dbf4d

I don't understand what happened though. If you psas invalid input to a Decimal, you'll normally get this message:

>>> decimal.Decimal("sdfsdf3f")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
decimal.InvalidOperation: [<class 'decimal.ConversionSyntax'>]

The exception message has a condition "decimal.ConversionSyntax". However in your case, the condition isdecimal.InvalidOperation itself. Too bad we can't see the input.

Looks like this might happen when the quantization is too precise:

>>> decimal.Decimal(3).quantize(decimal.Decimal('0.000000000000000000000000000000000000000000001'), rounding=decimal.ROUND_DOWN)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
decimal.InvalidOperation: [<class 'decimal.InvalidOperation'>]

or

>>> decimal.Decimal('inf')*0
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
decimal.InvalidOperation: [<class 'decimal.InvalidOperation'>]

See https://docs.python.org/3.8/library/decimal.html#decimal.InvalidOperation

Though, still no idea how that could happen in our test framework.

It looks like it also happens if some limit is exceeded e.g. decimal.Decimal("1e9999999999999999999") (wasn't able to trigger this with just a long number without exponent). This would be possible to trigger though unlikely.