blockchain.get_all_accounts() fails for limit > steps on appbase

[crokkon]

Expected behavior

blockchain.get_all_accounts(limit=2000, steps=1000) returns 2000 account names while internally doing two batch calls of 1000 accounts each. This should work on both appbase and non-appbase nodes

Actual behavior

blockchain.get_all_accounts(limit=2000, steps=1000) fails on appbase nodes when limit > steps

How to reproduce

>>> from beem import Steem
>>> from beem.blockchain import Blockchain
>>> s = Steem(node='https://api.steemit.com')
>>> s.rpc.get_use_appbase()
True
>>> len(list(b.get_all_accounts(limit=1000, steps=1000)))
1000
>>> len(list(b.get_all_accounts(limit=2000, steps=1000)))
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/beemapi/steemnoderpc.py", line 65, in rpcexec
    reply = super(SteemNodeRPC, self).rpcexec(payload)
  File "/usr/local/lib/python3.6/site-packages/beemapi/graphenerpc.py", line 381, in rpcexec
    raise RPCError(ret['error']['message'])
beemapi.exceptions.RPCError: Bad Cast:Invalid cast from object_type to string

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.6/site-packages/beem/blockchain.py", line 562, in get_all_accounts
    ret = self.steem.rpc.list_accounts({'start': lastname, 'limit': steps, 'order': 'by_name'}, api="database")["accounts"]
  File "/usr/local/lib/python3.6/site-packages/beemapi/graphenerpc.py", line 430, in method
    r = self.rpcexec(query)
  File "/usr/local/lib/python3.6/site-packages/beemapi/steemnoderpc.py", line 87, in rpcexec
    doRetry = self._check_error_message(e, self.error_cnt_call)
  File "/usr/local/lib/python3.6/site-packages/beemapi/steemnoderpc.py", line 146, in _check_error_message
    raise exceptions.UnhandledRPCError(msg)
beemapi.exceptions.UnhandledRPCError: Bad Cast:Invalid cast from object_type to string

It works on non-appbase nodes:

>>> s = Steem("wss://steemd.pevo.science")
>>> s.rpc.get_use_appbase()
False
>>> b = Blockchain(steem_instance=s)
>>> len(list(b.get_all_accounts(limit=2000, steps=1000)))
2000

Environment

# beempy --version
beempy, version 0.19.37
# python --version
Python 3.6.5

[holgern]

Thanks for the report. Fixed in 8137a6a.