Remove underscores from event parameters. (#1258)

* Remove underscores from event parameters.

Fixes #1175

* Add comment about ERC

CODE_STYLE.md

@@ -24,6 +24,12 @@ Any exception or additions specific to our project are documented below.
     }
     ```
 
+  The exception are the parameters of events. There is no chance of ambiguity
+  with these, so they should not have underscores. Not even if they are
+  specified on an ERC with underscores; removing them doesn't change the ABI,
+  so we should be consistent with the rest of the events in this repository
+  and remove them.
+
 * Internal and private state variables should have an underscore suffix.
 
     ```

contracts/mocks/ERC721ReceiverMock.sol

@@ -8,11 +8,11 @@ contract ERC721ReceiverMock is IERC721Receiver {
   bool internal reverts_;
 
   event Received(
-    address _operator,
-    address _from,
-    uint256 _tokenId,
-    bytes _data,
-    uint256 _gas
+    address operator,
+    address from,
+    uint256 tokenId,
+    bytes data,
+    uint256 gas
   );
 
   constructor(bytes4 _retval, bool _reverts) public {

contracts/token/ERC721/IERC721Basic.sol

@@ -40,19 +40,19 @@ contract IERC721Basic is IERC165 {
    */
 
   event Transfer(
-    address indexed _from,
-    address indexed _to,
-    uint256 indexed _tokenId
+    address indexed from,
+    address indexed to,
+    uint256 indexed tokenId
   );
   event Approval(
-    address indexed _owner,
-    address indexed _approved,
-    uint256 indexed _tokenId
+    address indexed owner,
+    address indexed approved,
+    uint256 indexed tokenId
   );
   event ApprovalForAll(
-    address indexed _owner,
-    address indexed _operator,
-    bool _approved
+    address indexed owner,
+    address indexed operator,
+    bool approved
   );
 
   function balanceOf(address _owner) public view returns (uint256 _balance);

test/token/ERC721/ERC721Basic.behavior.js

@@ -92,17 +92,17 @@ function shouldBehaveLikeERC721Basic (accounts) {
           it('emit only a transfer event', async function () {
             logs.length.should.be.equal(1);
             logs[0].event.should.be.equal('Transfer');
-            logs[0].args._from.should.be.equal(owner);
-            logs[0].args._to.should.be.equal(this.to);
-            logs[0].args._tokenId.should.be.bignumber.equal(tokenId);
+            logs[0].args.from.should.be.equal(owner);
+            logs[0].args.to.should.be.equal(this.to);
+            logs[0].args.tokenId.should.be.bignumber.equal(tokenId);
           });
         } else {
           it('emits only a transfer event', async function () {
             logs.length.should.be.equal(1);
             logs[0].event.should.be.equal('Transfer');
-            logs[0].args._from.should.be.equal(owner);
-            logs[0].args._to.should.be.equal(this.to);
-            logs[0].args._tokenId.should.be.bignumber.equal(tokenId);
+            logs[0].args.from.should.be.equal(owner);
+            logs[0].args.to.should.be.equal(this.to);
+            logs[0].args.tokenId.should.be.bignumber.equal(tokenId);
           });
         }
 
@@ -167,9 +167,9 @@ function shouldBehaveLikeERC721Basic (accounts) {
           it('emits only a transfer event', async function () {
             logs.length.should.be.equal(1);
             logs[0].event.should.be.equal('Transfer');
-            logs[0].args._from.should.be.equal(owner);
-            logs[0].args._to.should.be.equal(owner);
-            logs[0].args._tokenId.should.be.bignumber.equal(tokenId);
+            logs[0].args.from.should.be.equal(owner);
+            logs[0].args.to.should.be.equal(owner);
+            logs[0].args.tokenId.should.be.bignumber.equal(tokenId);
           });
 
           it('keeps the owner balance', async function () {
@@ -247,10 +247,10 @@ function shouldBehaveLikeERC721Basic (accounts) {
               result.receipt.logs.length.should.be.equal(2);
               const [log] = decodeLogs([result.receipt.logs[1]], ERC721Receiver, this.receiver.address);
               log.event.should.be.equal('Received');
-              log.args._operator.should.be.equal(owner);
-              log.args._from.should.be.equal(owner);
-              log.args._tokenId.toNumber().should.be.equal(tokenId);
-              log.args._data.should.be.equal(data);
+              log.args.operator.should.be.equal(owner);
+              log.args.from.should.be.equal(owner);
+              log.args.tokenId.toNumber().should.be.equal(tokenId);
+              log.args.data.should.be.equal(data);
             });
 
             it('should call onERC721Received from approved', async function () {
@@ -258,10 +258,10 @@ function shouldBehaveLikeERC721Basic (accounts) {
               result.receipt.logs.length.should.be.equal(2);
               const [log] = decodeLogs([result.receipt.logs[1]], ERC721Receiver, this.receiver.address);
               log.event.should.be.equal('Received');
-              log.args._operator.should.be.equal(approved);
-              log.args._from.should.be.equal(owner);
-              log.args._tokenId.toNumber().should.be.equal(tokenId);
-              log.args._data.should.be.equal(data);
+              log.args.operator.should.be.equal(approved);
+              log.args.from.should.be.equal(owner);
+              log.args.tokenId.toNumber().should.be.equal(tokenId);
+              log.args.data.should.be.equal(data);
             });
 
             describe('with an invalid token id', function () {
@@ -334,9 +334,9 @@ function shouldBehaveLikeERC721Basic (accounts) {
         it('emits an approval event', async function () {
           logs.length.should.be.equal(1);
           logs[0].event.should.be.equal('Approval');
-          logs[0].args._owner.should.be.equal(sender);
-          logs[0].args._approved.should.be.equal(address);
-          logs[0].args._tokenId.should.be.bignumber.equal(tokenId);
+          logs[0].args.owner.should.be.equal(sender);
+          logs[0].args.approved.should.be.equal(address);
+          logs[0].args.tokenId.should.be.bignumber.equal(tokenId);
         });
       };
 
@@ -447,9 +447,9 @@ function shouldBehaveLikeERC721Basic (accounts) {
 
             logs.length.should.be.equal(1);
             logs[0].event.should.be.equal('ApprovalForAll');
-            logs[0].args._owner.should.be.equal(sender);
-            logs[0].args._operator.should.be.equal(operator);
-            logs[0].args._approved.should.equal(true);
+            logs[0].args.owner.should.be.equal(sender);
+            logs[0].args.operator.should.be.equal(operator);
+            logs[0].args.approved.should.equal(true);
           });
         });
 
@@ -469,9 +469,9 @@ function shouldBehaveLikeERC721Basic (accounts) {
 
             logs.length.should.be.equal(1);
             logs[0].event.should.be.equal('ApprovalForAll');
-            logs[0].args._owner.should.be.equal(sender);
-            logs[0].args._operator.should.be.equal(operator);
-            logs[0].args._approved.should.equal(true);
+            logs[0].args.owner.should.be.equal(sender);
+            logs[0].args.operator.should.be.equal(operator);
+            logs[0].args.approved.should.equal(true);
           });
 
           it('can unset the operator approval', async function () {
@@ -497,9 +497,9 @@ function shouldBehaveLikeERC721Basic (accounts) {
 
             logs.length.should.be.equal(1);
             logs[0].event.should.be.equal('ApprovalForAll');
-            logs[0].args._owner.should.be.equal(sender);
-            logs[0].args._operator.should.be.equal(operator);
-            logs[0].args._approved.should.equal(true);
+            logs[0].args.owner.should.be.equal(sender);
+            logs[0].args.operator.should.be.equal(operator);
+            logs[0].args.approved.should.equal(true);
           });
         });
       });

test/token/ERC721/ERC721MintBurn.behavior.js

@@ -40,9 +40,9 @@ function shouldBehaveLikeMintAndBurnERC721 (accounts) {
         it('emits a transfer event', async function () {
           logs.length.should.be.equal(1);
           logs[0].event.should.be.equal('Transfer');
-          logs[0].args._from.should.be.equal(ZERO_ADDRESS);
-          logs[0].args._to.should.be.equal(to);
-          logs[0].args._tokenId.should.be.bignumber.equal(tokenId);
+          logs[0].args.from.should.be.equal(ZERO_ADDRESS);
+          logs[0].args.to.should.be.equal(to);
+          logs[0].args.tokenId.should.be.bignumber.equal(tokenId);
         });
       });
 
@@ -78,9 +78,9 @@ function shouldBehaveLikeMintAndBurnERC721 (accounts) {
         it('emits a burn event', async function () {
           logs.length.should.be.equal(1);
           logs[0].event.should.be.equal('Transfer');
-          logs[0].args._from.should.be.equal(sender);
-          logs[0].args._to.should.be.equal(ZERO_ADDRESS);
-          logs[0].args._tokenId.should.be.bignumber.equal(tokenId);
+          logs[0].args.from.should.be.equal(sender);
+          logs[0].args.to.should.be.equal(ZERO_ADDRESS);
+          logs[0].args.tokenId.should.be.bignumber.equal(tokenId);
         });
       });