Add ERC1155.totalSupply that returns overall supply count

.changeset/chilled-spiders-attack.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': major
+---
+
+`ERC1155Supply`: add a `totalSupply()` function that returns the total amount of token circulating, this change will restrict the total tokens minted across all ids to 2\*\*256-1 .

contracts/token/ERC1155/extensions/ERC1155Supply.sol

@@ -15,6 +15,7 @@ import "../ERC1155.sol";
  */
 abstract contract ERC1155Supply is ERC1155 {
  mapping(uint256 => uint256) private _totalSupply;
+ uint256 private _totalSupplyAll;
 
  /**
  * @dev Total amount of tokens in with a given id.
@@ -23,6 +24,13 @@ abstract contract ERC1155Supply is ERC1155 {
  return _totalSupply[id];
  }
 
+ /**
+ * @dev Total amount of tokens.
+ */
+ function totalSupply() public view virtual returns (uint256) {
+ return _totalSupplyAll;
+ }
+
  /**
  * @dev Indicates whether any token exist with a given id, or not.
  */
@@ -41,21 +49,33 @@ abstract contract ERC1155Supply is ERC1155 {
  bytes memory data
  ) internal virtual override {
  if (from == address(0)) {
+ uint256 totalMintAmount = 0;
  for (uint256 i = 0; i < ids.length; ++i) {
- _totalSupply[ids[i]] += amounts[i];
+ uint256 amount = amounts[i];
+ _totalSupply[ids[i]] += amount;
+ totalMintAmount += amount;
  }
+ _totalSupplyAll += totalMintAmount;
  }
 
  if (to == address(0)) {
+ uint256 totalBurnAmount = 0;
  for (uint256 i = 0; i < ids.length; ++i) {
  uint256 id = ids[i];
  uint256 amount = amounts[i];
  uint256 supply = _totalSupply[id];
  require(supply >= amount, "ERC1155: burn amount exceeds totalSupply");
  unchecked {
+ // Overflow not possible: amounts[i] <= totalSupply(i)
  _totalSupply[id] = supply - amount;
+ // Overflow not possible: sum(amounts[i]) <= sum(totalSupply(i)) <= totalSupplyAll
+ totalBurnAmount += amount;
  }
  }
+ unchecked {
+ // Overflow not possible: totalBurnAmount = sum(amounts[i]) <= sum(totalSupply(i)) <= totalSupplyAll
+ _totalSupplyAll -= totalBurnAmount;
+ }
  }
  super._update(from, to, ids, amounts, data);
  }

test/token/ERC1155/extensions/ERC1155Supply.test.js

@@ -1,7 +1,9 @@
-const { BN } = require('@openzeppelin/test-helpers');
+const { BN, constants } = require('@openzeppelin/test-helpers');
 
 const { expect } = require('chai');
 
+const { ZERO_ADDRESS } = constants;
+
 const ERC1155Supply = artifacts.require('$ERC1155Supply');
 
 contract('ERC1155Supply', function (accounts) {
@@ -25,7 +27,8 @@ contract('ERC1155Supply', function (accounts) {
  });
 
  it('totalSupply', async function () {
- expect(await this.token.totalSupply(firstTokenId)).to.be.bignumber.equal('0');
+ expect(await this.token.methods['totalSupply(uint256)'](firstTokenId)).to.be.bignumber.equal('0');
+ expect(await this.token.methods['totalSupply()']()).to.be.bignumber.equal('0');
  });
  });
 
@@ -40,7 +43,8 @@ contract('ERC1155Supply', function (accounts) {
  });
 
  it('totalSupply', async function () {
- expect(await this.token.totalSupply(firstTokenId)).to.be.bignumber.equal(firstTokenAmount);
+ expect(await this.token.methods['totalSupply(uint256)'](firstTokenId)).to.be.bignumber.equal(firstTokenAmount);
+ expect(await this.token.methods['totalSupply()']()).to.be.bignumber.equal(firstTokenAmount);
  });
  });
 
@@ -60,8 +64,13 @@ contract('ERC1155Supply', function (accounts) {
  });
 
  it('totalSupply', async function () {
- expect(await this.token.totalSupply(firstTokenId)).to.be.bignumber.equal(firstTokenAmount);
- expect(await this.token.totalSupply(secondTokenId)).to.be.bignumber.equal(secondTokenAmount);
+ expect(await this.token.methods['totalSupply(uint256)'](firstTokenId)).to.be.bignumber.equal(firstTokenAmount);
+ expect(await this.token.methods['totalSupply(uint256)'](secondTokenId)).to.be.bignumber.equal(
+ secondTokenAmount,
+ );
+ expect(await this.token.methods['totalSupply()']()).to.be.bignumber.equal(
+ firstTokenAmount.add(secondTokenAmount),
+ );
  });
  });
  });
@@ -78,7 +87,8 @@ contract('ERC1155Supply', function (accounts) {
  });
 
  it('totalSupply', async function () {
- expect(await this.token.totalSupply(firstTokenId)).to.be.bignumber.equal('0');
+ expect(await this.token.methods['totalSupply(uint256)'](firstTokenId)).to.be.bignumber.equal('0');
+ expect(await this.token.methods['totalSupply()']()).to.be.bignumber.equal('0');
  });
  });
 
@@ -99,9 +109,20 @@ contract('ERC1155Supply', function (accounts) {
  });
 
  it('totalSupply', async function () {
- expect(await this.token.totalSupply(firstTokenId)).to.be.bignumber.equal('0');
- expect(await this.token.totalSupply(secondTokenId)).to.be.bignumber.equal('0');
+ expect(await this.token.methods['totalSupply(uint256)'](firstTokenId)).to.be.bignumber.equal('0');
+ expect(await this.token.methods['totalSupply(uint256)'](secondTokenId)).to.be.bignumber.equal('0');
+ expect(await this.token.methods['totalSupply()']()).to.be.bignumber.equal('0');
+ });
+ });
+ });
+
+ context('other', function () {
+ it('supply unaffected by no-op', async function () {
+ this.token.safeTransferFrom(ZERO_ADDRESS, ZERO_ADDRESS, firstTokenId, firstTokenAmount, '0x', {
+ from: ZERO_ADDRESS,
  });
+ expect(await this.token.methods['totalSupply(uint256)'](firstTokenId)).to.be.bignumber.equal('0');
+ expect(await this.token.methods['totalSupply()']()).to.be.bignumber.equal('0');
  });
  });
 });