decentraland / land

⛰ Contract for LAND

LAND

Contracts for Decentraland's World.

Overview

The LAND contract keeps a record of all the land parcels, who their owner is, and what data is associated with them. The data associated can be an IPFS identifier, an IPNS url, or a simple HTTPS endpoint with a land description file.

Check this doc for further understanding.

License

Code released under the Apache v2.0 license.

land's Issues

Rename ammendReceived to ammendReceivedLand

Check array sizes at assignMultipleParcels

here

After claimForgottenParcel tokenOwner is not updated

New token owner is not updated in the local array.

[EstateRegistry] Change `msg.sender` to new parameter `address _owner` at initialize

Script to deploy multiple LAND parcels

Check Circle deployment

Use OZ base classes as a parent for the Registry

Handle transfer of parcels when not using safeTransferFrom()

• Make transfer() function to throw if using it to transfer to the EstateRegistry.
• Remove ammend function from the EstateRegistry as it will not be needed.

Add composable behavior into the Estate contract

The Estate contract should have the ability to receive the NFT representing a parcel and also to transfer it out from the Estate whenever the owner decides to do so.

• Update the ERC721Received to handle the addition of the received ERC721 into the internal array. (userData parameter)
• Add a transferOut() function to handle the unbundling of a parcel.
• Handle the case when safeTransferFrom() was not used in the source contract.
• Address mangling to create a unique id representing the assetId.

Note: The Composable attribute of this contract can be narrowed down to only supporting a LANDRegistry ERC721.

Reference: ethereum/EIPs#998

Add transferLandToEstate()

Should holders have to authorize themselves to updateLandData?

Currently a holder must do that in order to modify land data, here's an example test on how that works:

it('returns land data for a given set of parcel coordinates', async () => {
  await land.authorizeOperator(user, true, sentByUser)
  await land.updateLandData(0, 1, 'test_data', sentByUser)
  const data = await land.landData(0, 1, sentByUser)
  data.should.be.equal('test_data')
})

Is this necessary? If so, why?

Add a check to _pushToken to avoid adding an already existing token to a Estate

require(tokenIdEstate[tokenId] == 0);

Interacting with the LANDRegistry (?)

Hello,

I am very new to smart contracts, but managed my way to build this repository, and connect it with the mainnet via Infura. I want to retrieve the owner of a parcel, but I am not figuring out what am I doing wrong. Here's what I try:

truffle(livenet)> LANDRegistry.at("0x7e06a9512086bc44c51C07c2bF0Af338420c2A13").encodeTokenId.call(13,-7)
BigNumber {
s: 1,
e: 39,
c: [ 476395313689, 31384884872445, 4044754960377 ] }
truffle(livenet)>

truffle(livenet)> LANDRegistry.at("0x7e06a9512086bc44c51C07c2bF0Af338420c2A13").ownerOfLand.call(13,-7)
'0x0000000000000000000000000000000000000000'
truffle(livenet)>

So this cannot be true, since 13, -7 was sold in the auction and the team mentioned that the LAND is distributed among the auction winners. It would be great if somebody could give me the right nudge :)

Check UI to see if plazas/roads/district ownership breaks color code

• Check plaza
• Check estates
• Check road

Bump ERC721 version in order to support ERC721 standard interface

Related to decentraland/erc721#39

Add createEstateWithMetadata to allow creation and setMetadata in a single transaction

Documentation

Is there any documentation planned soon?

Trying to deploy Land contracts

Hello, I am trying to deploy the Land contracts and having some trouble. Could someone tell me the order they are deployed and what goes in function initialize(bytes) in the LANDRegistry contract? Any help would be greatly appreciated.

Add transferManyLandToEstate() to allow multiple transfers

About Estate

From the docs of FAQ about What is an Estate?

An estate is an association of two or more directly adjacent parcels of LAND. These parcels must be directly adjacent and cannot be separated by a road, plaza or any other parcel.

But, from the code

land/contracts/land/LANDRegistry.sol

Line 400 in 7cd5834

function _createEstate(

two non-adjacent parcels can also be combined into one estate.

Is there something wrong with me?

canDeploy modifier

Right now the following line is used in two deployment related functions:
require(authorizedDeploy[msg.sender]);

It may be relevant to move that logic into a modifier, specially if we implement require(condition, message) in the future.

Emit AddToken and RemoveToken when a token is added/removed from an Estate array

Identify accounts who are current deployers of the LANDRegistry

Update tests to use the new interfaces

Review recommendations as indicated by the audit

Evaluate if we need to remote district_id attribute

Make the Estate contract upgradeable

Add require() onERC721Received to check if estateId exists

Pass through metadata query from Parcel to Estate when required

This should work like:

1. Get metadata from Estate should query its own metadata and the same for Parcel.
2. Updating Metadata for each ERC721 (Estate, Parcel) should update its own metadata.

Script to convert a number of LAND parcels to Estate

Map functions that use state variables to the ones we are already using

The idea is to maintain the storage alignment as the contract is upgradeable and used with a Proxy, this means we might need to map state variables with different names (or structure) from the OZ implementation to our own while maintaining the same interface.

Check Estate owner is the same as the Estate you want to transfer the LAND

Nevermind!

Change expandNegative128BitCast from public to internal

Return is stopping land transfer

We should replace:

function transferLand(int x, int y, address to) public {
    return transfer(to, encodeTokenId(x, y));
  }

  function transferManyLand(int[] x, int[] y, address to) public {
    require(x.length == y.length);
    for (uint i = 0; i < x.length; i++) {
      return transfer(to, encodeTokenId(x[i], y[i]));
    }
  }

To

function transferLand(int x, int y, address to) public {
    transfer(to, encodeTokenId(x, y));
  }

  function transferManyLand(int[] x, int[] y, address to) public {
    require(x.length == y.length);
    for (uint i = 0; i < x.length; i++) {
      transfer(to, encodeTokenId(x[i], y[i]));
    }
  }

transferLand it is working anyways, but transferManyLand is only transferred one land and then break the process due return keyword

Update the EstateOwner contract into an ERC721

Convert the current EstateOwner implementation into an ERC721 compatible registry as it will make easier using the asset within the Marketplace and listing into other platforms.

• Refactor constructor
• Update single state variables to mappings accordingly in order to support multiple tokenIds
• Change current operator name into updateOperator or something meaningful
• Change EstateOwner to EstateRegistry (proposal)
• Update tests

Note: Use as a base for the ERC721 standard the OpenZeppelin implementation.

Reference: https://github.com/OpenZeppelin/openzeppelin-solidity/tree/master/contracts/token/ERC721

Remove destroy function

Decentraland contact owner should not be able to destroy LAND at will...

The destroy function is counter productive to the Decentraland project. No government or single entity should have control over your LAND.

land/contracts/land/LANDRegistry.sol

Line 44 in 07c0ec1

function destroy(uint256 assetId) onlyOwner public {

claimForgottenParcel could be executed endlessly

In LAND.sol -> claimForgottenParcel the latestPing is not updated and forgotten land could be reclaimed before the owner calls ping()

Smart Contract Address

What is your ERC-721/ERC-821 Smart Contract address for the land?

Remove the require which checks for at least one coordinate is included in the params `require(x.length > 0, "You should supply at least one coordinate")

Add tests for Events emit

Emit CreateEstate in the mint()

Make the LAND Transfer event ERC721 compatible (drop the extra data value)

Most platforms want to see the Transfer event similar to all other NFT contracts -- we can add another event to display the extra data we append.

claimForgottenParcel allows anyone to steal "forgotten" parcels

I am still new to Solidity so forgive me if I missed something obvious but....

In LAND.sol -> claimForgottenParcel there is no verification other than that the token is already owned and it hasn't been pinged in over a year.

Anyone can claim forgotten tokens for free? Or is it supposed to "require(msg.sender == claimContract);"?

docs needed

Run lint on Circle

Let the build break if the npm run lint command doesn't exit correctly

LANDRegistry make LANDAuction contract deployer