Investigate events emitted when selling canvas

[krisu-pl]

There seems to be something wrong with emitted events.
When accepting Sell offer, from and to addresses are the same.
When accepting Buy offer by the owner, the amount is 0 and to address is 0x0

[krisu-pl]

@k-misztal it may be caused because Solidity uses pointers instead of copying variables... check this out. If that's the case you might need to review the whole contract for this kind of bugs

[krisu-pl]

Same error as above, but in function acceptSellOffer.

First, you make the sender the owner of the canvas (correct).

canvas.owner = msg.sender;
cancelSellOffer(_canvasId);

emit CanvasSold(_canvasId, msg.value, sellOffer.seller, msg.sender);

But then you execute cancelSellOffer

 require(canvas.owner == msg.sender);
 canvasForSale[_canvasId] = SellOffer(false, msg.sender, 0, 0x0);

where you change the sell offer seller to msg.sender, which is actually the buyer in this case

[krisu-pl]

FYI moving emitting events above the critical lines solves the problem, but I'd still take a deeper look into the whole contract and other events

[krisu-pl]

One more thing, event CanvasNoLongerForSale is our only indicator of "Sell Offer Cancelled". It shouldn't be triggered when accepting sell offer as we would have 2 events in the history (Canvas Sold & Sell Offer Cancelled). I think cancelSellOffer function should be split into two, so you can reset the sell offer but not emit the event.

[k-misztal]

Fixed.