Loops of Length 311 are Too Big for init Functions

[xcthulhu]

I am having problems with using while loops in def init(): functions in Contracts.

Specifically, I have installed the following versions of serpent and pyethereum:

pip install -q --upgrade \
  git+git://github.com/ethereum/serpent.git@86649c54c209a662c943d664819fe01b8ebc3e2b \
  git+git://github.com/ethereum/pyethereum.git@23c7d1e551c3c94d11fdea66cfdb7d29b17b8a50

Here's my contract:

# array_init.se
data arr[312]

def init():
    i = 0
    while i < 311:
        self.arr[i] = 1
        i = i + 1

def foo():
    return 1

312 happens to be the length of the buffer used by Mersenne Twister.

If I replace 311 with 310, there are no problems.

Here's how I am testing this code:

from pyethereum import tester as t
s = t.state()
c = s.contract('array_init.se')
for _ in range(5):
    gas_start = s.block.gas_used
    print s.send(t.k0, c, 0, funid=0, abi=[])[0]

Should print 1 five times. Instead here's my exception and stacktrace:

---------------------------------------------------------------------------
Exception                                 Traceback (most recent call last)
<ipython-input-37-fa2ff0671689> in <module>()
      1 from pyethereum import tester as t
      2 s = t.state()
----> 3 c = s.contract('array_init.se')
      4 for _ in range(5):
      5     gas_start = s.block.gas_used

/usr/local/lib/python2.7/site-packages/pyethereum/tester.pyc in contract(self, code, sender, endowment)
     60     def contract(self, code, sender=k0, endowment=0):
     61         evm = serpent.compile(code)
---> 62         o = self.evm(evm, sender, endowment)
     63         assert len(self.block.get_code(o)), "Contract code empty"
     64         return o

/usr/local/lib/python2.7/site-packages/pyethereum/tester.pyc in evm(self, evm, sender, endowment)
     70         (s, a) = pb.apply_transaction(self.block, tx)
     71         if not s:
---> 72             raise Exception("Contract creation failed")
     73         return a
     74 

Exception: Contract creation failed

[joeykrug]

You're using so much gas contract creation is failing. So this would never work on the current live chain. That said if you want to use it anyway for w/e reason do t.gas_limit = 200000000 and then it'll have a higher gas limit and work