web3.py: InsufficientDataBytes: Tried to read 32 bytes. Only got 0 bytes (This One Appears To Be Different)

Web3 Version: 4.8.2 Solidity: 0.4.18, 0.5.3 (Both Installed Via Py-Solc) Geth Version: 1.7 (Built From Source), 1.8.23 (Binary), Master (as of 2/23/19) (Built From Source)

• Python: 3.6
• OS: Ubuntu 18.04
• pip freeze output

aenum==2.1.2
asn1crypto==0.24.0
astor==0.7.1
attrdict==2.0.0
attrs==18.2.0
Automat==0.7.0
autopep8==1.4.3
base58==1.0.3
bitcoin==1.1.42
blessings==1.7
bpython==0.17.1
bumpversion==0.5.3
certifi==2018.11.29
cffi==1.11.5
chardet==3.0.4
Click==7.0
colorlog==4.0.2
constantly==15.1.0
coverage==4.5.2
coveralls==1.5.1
coz-bytecode==0.5.1
cryptography==2.4.2
curtsies==0.3.0
cycler==0.10.0
cytoolz==0.9.0.1
docopt==0.6.2
ecdsa==0.13
eth-abi==1.3.0 (I just updated this from 1.2.2 in hopes of the issue being solved)
eth-account==0.3.0
eth-hash==0.2.0
eth-keyfile==0.5.1
eth-keys==0.2.0b3
eth-rlp==0.1.2
eth-typing==2.0.0
eth-utils==1.3.0
Events==0.3
Flask==1.0.2
Flask-Cors==3.0.7
Flask-Limiter==1.0.1
Flask-REST==1.3
furl==2.0.0
gevent==1.4.0
greenlet==0.4.15
hexbytes==0.1.0
hyperlink==18.0.0
idna==2.8
incremental==17.5.0
inflection==0.2.0
itsdangerous==1.1.0
Jinja2==2.10
klein==17.10.0
limits==1.3
logzero==1.5.0
lru-dict==1.1.6
MarkupSafe==1.1.0
memory-profiler==0.55.0
mmh3==2.5.1
mock==2.0.0
Mongothon==0.8.0
mpmath==1.1.0
neo-boa==0.5.6
-e git+https://github.com/CityOfZion/neo-python.git@fe90f62e123d720d4281c79af0598d9df9e776fb#egg=neo_python
neo-python-rpc==0.2.1
neocore==0.5.6
orderedmultidict==1.0
parse==1.9.0
parsimonious==0.8.1
pbr==5.1.1
peewee==3.8.1
pexpect==4.6.0
pluggy==0.8.1
plyvel==1.0.5
prompt-toolkit==2.0.7
psutil==5.4.8
ptyprocess==0.6.0
py==1.7.0
py-solc==2.1.0
pycodestyle==2.4.0
pycparser==2.19
pycryptodome==3.7.2
Pygments==2.3.1
PyHamcrest==1.9.0
pymitter==0.2.3
pymongo==3.7.2
Pympler==0.6
pyparsing==2.3.1
python-dateutil==2.7.5
pytz==2018.9
requests==2.21.0
rlp==1.0.3
Schemer==0.2.11
scrypt==0.8.6
semantic-version==2.6.0
six==1.12.0
toolz==0.9.0
tqdm==4.29.1
Twisted==18.9.0
typing==3.6.6
urllib3==1.24.1
uuid==1.30
virtualenv==16.2.0
wcwidth==0.1.7
web3==4.8.2
websockets==6.0
Werkzeug==0.14.1
zope.interface==4.6.0

What was wrong?

I have had this specific contract deployed on Ropsten for just over a month but the exact same code has been deployed and used many times (at least 4 different successful deployments). About 4 days ago seemingly out of nowhere the error “InsufficientDataBytes: Tried to read 32 bytes. Only got 0 bytes” arose. The contract had been used for about 26 days consecutively. There was literally no change in the code base between the contract communication working and it no longer working. I have not found ANY reason as to why this happened.

I wanted to make sure this was not somehow a delayed result of a faulty smart contract so I have confirmed that the exact same issue happens with the example code below. Because I received the exact same issue with the example code I chose to show the example code for simplicity:

import json
import web3

from web3 import Web3
from solc import compile_source
from web3.contract import ConciseContract

contract_source_code = '''
pragma solidity ^0.4.18;

contract Greeter {
    string public greeting;

    function Greeter() public {
        greeting = 'Hello';
    }

    function setGreeting(string _greeting) public {
        greeting = _greeting;
    }

    function greet() view public returns (string) {
        return greeting;
    }
}
'''

compiled_sol = compile_source(contract_source_code)
contract_interface = compiled_sol['<stdin>:Greeter']

w3 = Web3(Web3.HTTPProvider('http://localhost:8545'))

w3.eth.defaultAccount = w3.eth.accounts[0]

w3.personal.unlockAccount(w3.personal.listAccounts[0], "password")

print(w3.eth.defaultAccount)

Greeter = w3.eth.contract(abi=contract_interface['abi'], bytecode=contract_interface['bin'])

tx_hash = Greeter.constructor().transact()

tx_receipt = w3.eth.waitForTransactionReceipt(tx_hash)

greeter = w3.eth.contract(
    address=tx_receipt.contractAddress,
    abi=contract_interface['abi'],
)

print('Default contract greeting: {}'.format(
    greeter.functions.greet().call()
))

print('Setting the greeting to Nihao...')
tx_hash = greeter.functions.setGreeting('Nihao').transact()

w3.eth.waitForTransactionReceipt(tx_hash)

print('Updated contract greeting: {}'.format(
    greeter.functions.greet().call()
))

reader = ConciseContract(greeter)
assert reader.greet() == "Nihao"

Here is the traceback:

Traceback (most recent call last):
Traceback (most recent call last):
  File "ENVPATH/lib/python3.6/site-packages/web3/contract.py", line 1374, in call_contract_function
    output_data = decode_abi(output_types, return_data)
  File "ENVPATH/lib/python3.6/site-packages/eth_abi/abi.py", line 96, in decode_abi
    return decoder(stream)
  File "ENVPATH/lib/python3.6/site-packages/eth_abi/decoding.py", line 118, in __call__
    return self.decode(stream)
  File "ENVPATH/lib/python3.6/site-packages/eth_utils/functional.py", line 46, in inner
    return callback(fn(*args, **kwargs))
  File "ENVPATH/lib/python3.6/site-packages/eth_abi/decoding.py", line 164, in decode
    yield decoder(stream)
  File "ENVPATH/lib/python3.6/site-packages/eth_abi/decoding.py", line 118, in __call__
    return self.decode(stream)
  File "ENVPATH/lib/python3.6/site-packages/eth_abi/decoding.py", line 133, in decode
    start_pos = decode_uint_256(stream)
  File "ENVPATH/lib/python3.6/site-packages/eth_abi/decoding.py", line 118, in __call__
    return self.decode(stream)
  File "ENVPATH/lib/python3.6/site-packages/eth_abi/decoding.py", line 186, in decode
    raw_data = self.read_data_from_stream(stream)
  File "ENVPATH/lib/python3.6/site-packages/eth_abi/decoding.py", line 296, in read_data_from_stream
    len(data),
eth_abi.exceptions.InsufficientDataBytes: Tried to read 32 bytes.  Only got 0 bytes

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "PROJECTPATH/testContract.py", line 67, in <module>
    greeter.functions.greet().call()
  File "ENVPATH/lib/python3.6/site-packages/web3/contract.py", line 1115, in call
    **self.kwargs
  File "ENVPATH/lib/python3.6/site-packages/web3/contract.py", line 1396, in call_contract_function
    raise BadFunctionCallOutput(msg) from e
web3.exceptions.BadFunctionCallOutput: Could not decode contract function call greet return data b'' for output_types ['string']

How can it be fixed?

I have no idea at the moment.