From 961208382660991e7679eb03865a2785e2c8cabe Mon Sep 17 00:00:00 2001
From: Francisco <fg@frang.io>
Date: Mon, 4 Sep 2023 10:54:21 -0300
Subject: [PATCH] Refactor ERC721 `_requireMinted` and `ownerOf` (#4566)

---
 .changeset/proud-spiders-attend.md            |  5 ++++
 contracts/token/ERC721/ERC721.sol             | 23 ++++++++++---------
 .../ERC721/extensions/ERC721URIStorage.sol    |  2 +-
 3 files changed, 18 insertions(+), 12 deletions(-)
 create mode 100644 .changeset/proud-spiders-attend.md

diff --git a/.changeset/proud-spiders-attend.md b/.changeset/proud-spiders-attend.md
new file mode 100644
index 00000000000..a8f7694c709
--- /dev/null
+++ b/.changeset/proud-spiders-attend.md
@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': major
+---
+
+`ERC721`: Renamed `_requireMinted` to `_requireOwned` and added a return value with the current owner. Implemented `ownerOf` in terms of `_requireOwned`.
diff --git a/contracts/token/ERC721/ERC721.sol b/contracts/token/ERC721/ERC721.sol
index d56e3377577..efca4b4342a 100644
--- a/contracts/token/ERC721/ERC721.sol
+++ b/contracts/token/ERC721/ERC721.sol
@@ -65,11 +65,7 @@ abstract contract ERC721 is Context, ERC165, IERC721, IERC721Metadata, IERC721Er
      * @dev See {IERC721-ownerOf}.
      */
     function ownerOf(uint256 tokenId) public view virtual returns (address) {
-        address owner = _ownerOf(tokenId);
-        if (owner == address(0)) {
-            revert ERC721NonexistentToken(tokenId);
-        }
-        return owner;
+        return _requireOwned(tokenId);
     }
 
     /**
@@ -90,7 +86,7 @@ abstract contract ERC721 is Context, ERC165, IERC721, IERC721Metadata, IERC721Er
      * @dev See {IERC721Metadata-tokenURI}.
      */
     function tokenURI(uint256 tokenId) public view virtual returns (string memory) {
-        _requireMinted(tokenId);
+        _requireOwned(tokenId);
 
         string memory baseURI = _baseURI();
         return bytes(baseURI).length > 0 ? string.concat(baseURI, tokenId.toString()) : "";
@@ -116,7 +112,7 @@ abstract contract ERC721 is Context, ERC165, IERC721, IERC721Metadata, IERC721Er
      * @dev See {IERC721-getApproved}.
      */
     function getApproved(uint256 tokenId) public view virtual returns (address) {
-        _requireMinted(tokenId);
+        _requireOwned(tokenId);
 
         return _getApproved(tokenId);
     }
@@ -397,7 +393,7 @@ abstract contract ERC721 is Context, ERC165, IERC721, IERC721Metadata, IERC721Er
      * Emits an {Approval} event.
      */
     function _approve(address to, uint256 tokenId, address auth) internal virtual returns (address) {
-        address owner = ownerOf(tokenId);
+        address owner = _requireOwned(tokenId);
 
         // We do not use _isAuthorized because single-token approvals should not be able to call approve
         if (auth != address(0) && owner != auth && !isApprovedForAll(owner, auth)) {
@@ -427,12 +423,17 @@ abstract contract ERC721 is Context, ERC165, IERC721, IERC721Metadata, IERC721Er
     }
 
     /**
-     * @dev Reverts if the `tokenId` has not been minted yet.
+     * @dev Reverts if the `tokenId` doesn't have a current owner (it hasn't been minted, or it has been burned).
+     * Returns the owner.
+     *
+     * Overrides to ownership logic should be done to {_ownerOf}.
      */
-    function _requireMinted(uint256 tokenId) internal view virtual {
-        if (_ownerOf(tokenId) == address(0)) {
+    function _requireOwned(uint256 tokenId) internal view returns (address) {
+        address owner = _ownerOf(tokenId);
+        if (owner == address(0)) {
             revert ERC721NonexistentToken(tokenId);
         }
+        return owner;
     }
 
     /**
diff --git a/contracts/token/ERC721/extensions/ERC721URIStorage.sol b/contracts/token/ERC721/extensions/ERC721URIStorage.sol
index b2adbbea3c2..e515f236966 100644
--- a/contracts/token/ERC721/extensions/ERC721URIStorage.sol
+++ b/contracts/token/ERC721/extensions/ERC721URIStorage.sol
@@ -32,7 +32,7 @@ abstract contract ERC721URIStorage is IERC4906, ERC721 {
      * @dev See {IERC721Metadata-tokenURI}.
      */
     function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
-        _requireMinted(tokenId);
+        _requireOwned(tokenId);
 
         string memory _tokenURI = _tokenURIs[tokenId];
         string memory base = _baseURI();