Add HasNoEther

contracts/ownership/HasNoEther.sol

@@ -0,0 +1,42 @@
+pragma solidity ^0.4.8;
+
+import "./Ownable.sol";
+
+/// @title Contracts that should not own Ether
+/// @author Remco Bloemen <remco@2π.com>
+///
+/// This tries to block incoming ether to prevent accidental
+/// loss of Ether. Should Ether end up in the contrat, it will
+/// allow the owner to reclaim this ether.
+///
+/// @notice Ether can still be send to this contract by:
+///  * calling functions labeled `payable`
+///  * `selfdestruct(contract_address)`
+///  * mining directly to the contract address
+contract HasNoEther is Ownable {
+
+  /// Constructor that rejects incoming Ether
+  /// @dev The flag `payabe` is added so we can access `msg.value`
+  ///      without compiler warning. If we leave out payable, then
+  ///      Solidity will allow inheriting contracts to implement a
+  ///      payable constructor. By doing it this way we prevent a
+  ///      payable constructor from working.
+  ///      Alternatively we could use assembly to access msg.value.
+  function HasNoEther() payable {
+    if(msg.value > 0) {
+      throw;
+    }
+  }
+
+  /// Disallow direct send by settings a default function without `payable`
+  function() external {
+  }
+
+  /// Transfer all Ether owned by the contract to the owner
+  /// @dev What if owner is itself a contract marked HasNoEther?
+  function reclaimEther() external onlyOwner {
+    if(!owner.send(this.balance)) {
+      throw;
+    }
+  }
+}

test/HasNoEther.js

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+'use strict';
+import expectThrow from './helpers/expectThrow';
+import toPromise from './helpers/toPromise';
+const HasNoEther = artifacts.require('../contracts/lifecycle/HasNoEther.sol');
+const HasNoEtherTest = artifacts.require('../helpers/HasNoEtherTest.sol');
+const ForceEther = artifacts.require('../helpers/ForceEther.sol');
+
+contract('HasNoEther', function(accounts) {
+  const amount = web3.toWei('1', 'ether');
+
+  it('should be constructorable', async function() {
+    let hasNoEther = await HasNoEtherTest.new();
+  });
+
+  it('should not accept ether in constructor', async function() {
+    await expectThrow(HasNoEtherTest.new({value: amount}));
+  });
+
+  it('should not accept ether', async function() {
+    let hasNoEther = await HasNoEtherTest.new();
+
+    await expectThrow(
+      toPromise(web3.eth.sendTransaction)({
+        from: accounts[1],
+        to: hasNoEther.address,
+        value: amount,
+      }),
+    );
+  });
+
+  it('should allow owner to reclaim ether', async function() {
+    // Create contract
+    let hasNoEther = await HasNoEtherTest.new();
+    const startBalance = await web3.eth.getBalance(hasNoEther.address);
+    assert.equal(startBalance, 0);
+
+    // Force ether into it
+    await ForceEther.new(hasNoEther.address, {value: amount});
+    const forcedBalance = await web3.eth.getBalance(hasNoEther.address);
+    assert.equal(forcedBalance, amount);
+
+    // Reclaim
+    const ownerStartBalance = await web3.eth.getBalance(accounts[0]);
+    await hasNoEther.reclaimEther();
+    const ownerFinalBalance = await web3.eth.getBalance(accounts[0]);
+    const finalBalance = await web3.eth.getBalance(hasNoEther.address);
+    assert.equal(finalBalance, 0);
+    assert.isAbove(ownerFinalBalance, ownerStartBalance);
+  });
+
+  it('should allow only owner to reclaim ether', async function() {
+    // Create contract
+    let hasNoEther = await HasNoEtherTest.new({from: accounts[0]});
+
+    // Force ether into it
+    await ForceEther.new(hasNoEther.address, {value: amount});
+    const forcedBalance = await web3.eth.getBalance(hasNoEther.address);
+    assert.equal(forcedBalance, amount);
+
+    // Reclaim
+    await expectThrow(hasNoEther.reclaimEther({from: accounts[1]}));
+  });
+});

test/helpers/ForceEther.sol

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+pragma solidity ^0.4.8;
+
+// @title Force Ether into a contract.
+// @notice  even
+// if the contract is not payable.
+// @notice To use, construct the contract with the target as argument.
+// @author Remco Bloemen <remco@neufund.org>
+contract ForceEther  {
+  function ForceEther(address target) payable {
+    // Selfdestruct transfers all Ether to the arget address
+    selfdestruct(target);
+  }
+}

test/helpers/HasNoEtherTest.sol

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+pragma solidity ^0.4.8;
+
+import "../../contracts/ownership/HasNoEther.sol";
+
+contract HasNoEtherTest is HasNoEther {
+
+  // Constructor with explicit payable — should still fail
+  function HasNoEtherTest() payable {
+
+  }
+
+  // Default function with explicit payable — should still fail
+  function() external payable {
+    throw;
+  }
+
+}

test/helpers/expectThrow.js

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+export default async promise => {
+  try {
+    await promise;
+  } catch (error) {
+    // TODO: Check jump destination to destinguish between a throw
+    //       and an actual invalid jump.
+    const invalidJump = error.message.search('invalid JUMP') >= 0;
+    assert(invalidJump, "Expected throw, got '" + error + "' instead");
+    return;
+  }
+  assert.fail('Expected throw not received');
+};

test/helpers/toPromise.js

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+export default func =>
+  (...args) =>
+    new Promise((accept, reject) =>
+      func(...args, (error, data) => error ? reject(error) : accept(data)));