WIP: Fix transfer dividendability

contracts/token/ERC20DividendableEth.sol

@@ -17,6 +17,7 @@ contract ERC20DividendableEth is ERC20MintableDetailed {
 
     uint256 public dividendsPerToken; // This is a decimal number
     mapping(address => uint256) public lastDPT; // These are decimal numbers
+    mapping(address => uint256) public adjustmentDPT;
 
     constructor(
         string memory name,
@@ -31,6 +32,52 @@ contract ERC20DividendableEth is ERC20MintableDetailed {
         releaseDividends(msg.value);
     }
 
+    /**
+     * @dev See {IERC20-transfer}.
+     *
+     * Requirements:
+     *
+     * - `recipient` cannot be the zero address.
+     * - the caller must have a balance of at least `amount`.
+     */
+    function transfer(
+        address recipient,
+        uint256 amount
+    ) public returns (bool) {
+        uint256 weight = amount.divd(this.balanceOf(recipient));
+        uint256 differentialDPT = lastDPT[msg.sender].subd(lastDPT[recipient]);
+        uint256 weightedDifferential = differentialDPT.muld(weight);
+        adjustmentDPT[recipient] = adjustmentDPT[recipient]
+            .addd(weightedDifferential);
+        return super.transfer(recipient, amount);
+    }
+
+    /**
+     * @dev See {IERC20-transferFrom}.
+     *
+     * Emits an {Approval} event indicating the updated allowance. This is not
+     * required by the EIP. See the note at the beginning of {ERC20};
+     *
+     * Requirements:
+     * - `sender` and `recipient` cannot be the zero address.
+     * - `sender` must have a balance of at least `amount`.
+     * - the caller must have allowance for `sender`'s tokens of at least
+     * `amount`.
+     */
+    function transferFrom(
+        address sender,
+        address recipient,
+        uint256 amount
+    ) public returns (bool) {
+        uint256 weight = amount.divd(this.balanceOf(recipient));
+        uint256 differentialDPT = lastDPT[sender]
+            .subd(lastDPT[recipient]);
+        uint256 weightedDifferential = differentialDPT.muld(weight);
+        adjustmentDPT[recipient] = adjustmentDPT[recipient]
+            .addd(weightedDifferential);
+        return super.transferFrom(sender, recipient, amount);
+    }
+
     /**
      * @dev Function to update the account of the sender
      * @notice Will revert if account need not be updated
@@ -58,8 +105,9 @@ contract ERC20DividendableEth is ERC20MintableDetailed {
     {
         uint256 owing = dividendsOwing(account);
         require(owing > 0, "Account need not be updated now.");
-        account.transfer(owing);
+        adjustmentDPT[account] = 0;
         lastDPT[account] = dividendsPerToken;
+        account.transfer(owing);
         return owing;
     }
 
@@ -68,7 +116,8 @@ contract ERC20DividendableEth is ERC20MintableDetailed {
      * @param account The account for which to compute the dividends
      */
     function dividendsOwing(address account) internal view returns(uint256) {
-        uint256 owedDPT = dividendsPerToken.subd(lastDPT[account]);
+        uint256 owedDPT = dividendsPerToken
+            .subd(lastDPT[account]).addd(adjustmentDPT[account]);
         return this.balanceOf(account).muld(owedDPT);
     }
 

package.json

@@ -41,7 +41,7 @@
         "@hq20/fixidity": "^0.1.0-alpha.1"
     },
     "devDependencies": {
-        "@hq20/fixidity": "0.1.0-alpha.1",
+        "@hq20/fixidity": "0.1.0-alpha.2",
         "@openzeppelin/contracts": "2.5.0",
         "@openzeppelin/test-helpers": "0.5.4",
         "@truffle/hdwallet-provider": "1.0.31",

test/token/ERC20DividendableEth.test.ts

@@ -1,7 +1,7 @@
 import { should } from 'chai';
 
 // tslint:disable-next-line:no-var-requires
-const { balance, BN, constants, ether, expectEvent, expectRevert, send } = require('@openzeppelin/test-helpers');
+const { BN, ether, expectRevert } = require('@openzeppelin/test-helpers');
 
 import { TestERC20DividendableEthInstance } from '../../types/truffle-contracts';
 
@@ -22,6 +22,7 @@ contract('ERC20DividendableEth', (accounts) => {
     const dividendsPerToken = ether('0.1');
     const claimedDividends1 = ether('4');
     const claimedDividends2 = ether('6');
+    const transferTokens = ether('6');
 
     let erc20dividendableEth: TestERC20DividendableEthInstance;
 
@@ -91,4 +92,26 @@ contract('ERC20DividendableEth', (accounts) => {
         BN(await erc20dividendableEth.claimDividends.call({ from: account1 }))
             .should.be.bignumber.equal(claimedDividends2);
     });
+
+    /**
+     * @test {ERC20DividendableEth#updateAccount} and {ERC20DividendableEth#claimDividends}
+     */
+    it('dividends can be claimed after transfer of dividends-bearing tokens', async () => {
+        await erc20dividendableEth.releaseDividends({ from: user1, value: releasedDividends.toString()});
+        await erc20dividendableEth.claimDividends({ from: account2 });
+        await erc20dividendableEth.transfer(account2, transferTokens, { from: account1 });
+        BN(await erc20dividendableEth.claimDividends.call({ from: account2 }))
+            .should.be.bignumber.gt(ether('6.59')).and.lt(ether('6.61'));
+    });
+
+    /**
+     * @test {ERC20DividendableEth#updateAccount} and {ERC20DividendableEth#claimDividends}
+     */
+    it('dividends can be claimed after transfer of non-dividends-bearing tokens', async () => {
+        await erc20dividendableEth.releaseDividends({ from: user1, value: releasedDividends.toString()});
+        await erc20dividendableEth.claimDividends({ from: account1 });
+        await erc20dividendableEth.transfer(account2, transferTokens, { from: account1 });
+        BN(await erc20dividendableEth.claimDividends.call({ from: account2 }))
+            .should.be.bignumber.equal(claimedDividends2);
+    });
 });

yarn.lock

@@ -115,12 +115,12 @@
     "@ethersproject/constants" ">=5.0.0-beta.128"
     "@ethersproject/logger" ">=5.0.0-beta.129"
 
-"@hq20/[email protected].1":
-  version "0.1.0-alpha.1"
-  resolved "https://registry.yarnpkg.com/@hq20/fixidity/-/fixidity-0.1.0-alpha.1.tgz#c33878c390815e48d80cc2bee6e9bd90943a912f"
-  integrity sha512-MPrDHLWny6qO5hbfjT0un7gNCt9HnJRnII4/NFKKIiFVaao2OImtfvLuJhtpv1vX7oDH73Z4eSXW43dmWuIXsQ==
+"@hq20/[email protected].2":
+  version "0.1.0-alpha.2"
+  resolved "https://registry.yarnpkg.com/@hq20/fixidity/-/fixidity-0.1.0-alpha.2.tgz#a3e0ddcc71aac68578757d89a167470766b621e0"
+  integrity sha512-slSKTCgtymLY2mo7aB4P7qq65SR46lI4zcyeg30f2TLuz01oa4Aa+EX/PRewHV5ZFKnhDCnMfy0s6SeIgQMGbA==
   dependencies:
-    "@truffle/hdwallet-provider" "1.0.29"
+    "@truffle/hdwallet-provider" "1.0.31"
     bignumber.js "9.0.0"
 
 "@hq20/[email protected]":
@@ -232,21 +232,6 @@
   resolved "https://registry.yarnpkg.com/@truffle/error/-/error-0.0.8.tgz#dc94ca36393403449d4b7461bf9452c241e53ec1"
   integrity sha512-x55rtRuNfRO1azmZ30iR0pf0OJ6flQqbax1hJz+Avk1K5fdmOv5cr22s9qFnwTWnS6Bw0jvJEoR0ITsM7cPKtQ==
 
-"@truffle/[email protected]":
-  version "1.0.29"
-  resolved "https://registry.yarnpkg.com/@truffle/hdwallet-provider/-/hdwallet-provider-1.0.29.tgz#711bf29049750fe629edb8c304ee5c6b04919a92"
-  integrity sha512-GN/eUINLXHnsUPx3PJvGd6WKnAOXP0MYK/aVhlE7PekYapHjimg0EVo8HrnDSQw6LxYRFiXP3lhyEK6J9witbg==
-  dependencies:
-    any-promise "^1.3.0"
-    bindings "^1.5.0"
-    bip39 "^2.4.2"
-    ethereum-protocol "^1.0.1"
-    ethereumjs-tx "^1.0.0"
-    ethereumjs-util "^6.1.0"
-    ethereumjs-wallet "^0.6.3"
-    web3 "1.2.1"
-    web3-provider-engine "https://github.com/trufflesuite/provider-engine#web3-one"
-
 "@truffle/[email protected]":
   version "1.0.31"
   resolved "https://registry.yarnpkg.com/@truffle/hdwallet-provider/-/hdwallet-provider-1.0.31.tgz#fafb4caa7a1bc234dd2af3543fa98eb491f257e1"
@@ -260,7 +245,7 @@
     ethereumjs-util "^6.1.0"
     ethereumjs-wallet "^0.6.3"
     web3 "1.2.1"
-    web3-provider-engine "git+https://github.com/trufflesuite/provider-engine.git#web3-one"
+    web3-provider-engine "https://github.com/trufflesuite/provider-engine#web3-one"
 
 "@truffle/interface-adapter@^0.3.0":
   version "0.3.3"
@@ -7885,7 +7870,6 @@ [email protected]:
 
 "web3-provider-engine@git+https://github.com/trufflesuite/provider-engine.git#web3-one":
   version "14.0.6"
-  uid "3538c60bc4836b73ccae1ac3f64c8fed8ef19c1a"
   resolved "git+https://github.com/trufflesuite/provider-engine.git#3538c60bc4836b73ccae1ac3f64c8fed8ef19c1a"
   dependencies:
     async "^2.5.0"
@@ -7909,31 +7893,6 @@ [email protected]:
     xhr "^2.2.0"
     xtend "^4.0.1"
 
-"web3-provider-engine@https://github.com/trufflesuite/provider-engine#web3-one":
-  version "14.0.6"
-  resolved "https://github.com/trufflesuite/provider-engine#3538c60bc4836b73ccae1ac3f64c8fed8ef19c1a"
-  dependencies:
-    async "^2.5.0"
-    backoff "^2.5.0"
-    clone "^2.0.0"
-    cross-fetch "^2.1.0"
-    eth-block-tracker "^3.0.0"
-    eth-json-rpc-infura "^3.1.0"
-    eth-sig-util "^1.4.2"
-    ethereumjs-block "^1.2.2"
-    ethereumjs-tx "^1.2.0"
-    ethereumjs-util "^5.1.5"
-    ethereumjs-vm "^2.3.4"
-    json-rpc-error "^2.0.0"
-    json-stable-stringify "^1.0.1"
-    promise-to-callback "^1.0.0"
-    readable-stream "^2.2.9"
-    request "^2.85.0"
-    semaphore "^1.0.3"
-    ws "^5.1.1"
-    xhr "^2.2.0"
-    xtend "^4.0.1"
-
 [email protected]:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/web3-providers-http/-/web3-providers-http-1.2.1.tgz#c93ea003a42e7b894556f7e19dd3540f947f5013"