Add replacements for TokenApprovalRef

Author: Vectorized

contracts/ERC721AStorage.sol

@@ -2,9 +2,12 @@
 
 pragma solidity ^0.8.0;
 
-import {ERC721AUpgradeable} from './ERC721AUpgradeable.sol';
-
 library ERC721AStorage {
+    // Reference type for token approval.
+    struct TokenApprovalRef {
+        address value;
+    }
+
     struct Layout {
         // =============================================================
         //                            STORAGE
@@ -38,7 +41,7 @@ library ERC721AStorage {
         // - [192..255] `aux`
         mapping(address => uint256) _packedAddressData;
         // Mapping from token ID to approved address.
-        mapping(uint256 => ERC721AUpgradeable.TokenApprovalRef) _tokenApprovals;
+        mapping(uint256 => ERC721AStorage.TokenApprovalRef) _tokenApprovals;
         // Mapping from owner to operator approvals
         mapping(address => mapping(address => bool)) _operatorApprovals;
     }

contracts/ERC721AUpgradeable.sol

@@ -37,10 +37,6 @@ interface ERC721A__IERC721ReceiverUpgradeable {
  */
 contract ERC721AUpgradeable is ERC721A__Initializable, IERC721AUpgradeable {
     using ERC721AStorage for ERC721AStorage.Layout;
-    // Reference type for token approval.
-    struct TokenApprovalRef {
-        address value;
-    }
 
     // =============================================================
     //                           CONSTANTS
@@ -480,7 +476,7 @@ contract ERC721AUpgradeable is ERC721A__Initializable, IERC721AUpgradeable {
         view
         returns (uint256 approvedAddressSlot, address approvedAddress)
     {
-        TokenApprovalRef storage tokenApproval = ERC721AStorage.layout()._tokenApprovals[tokenId];
+        ERC721AStorage.TokenApprovalRef storage tokenApproval = ERC721AStorage.layout()._tokenApprovals[tokenId];
         // The following is equivalent to `approvedAddress = _tokenApprovals[tokenId]`.
         assembly {
             approvedAddressSlot := tokenApproval.slot

scripts/replace-imports.js

@@ -2,14 +2,14 @@
 const fs = require('fs');
 const glob = require('glob');
 
-// rename files
+// Rename files.
 fs.renameSync('contracts/Initializable.sol', 'contracts/ERC721A__Initializable.sol');
 fs.renameSync('contracts/InitializableStorage.sol', 'contracts/ERC721A__InitializableStorage.sol');
 
-// loop through all files with contracts/**/*.sol pattern
+// Loop through all files with contracts/**/*.sol pattern.
 glob('contracts/**/*.sol', null, function (err, files) {
   files.forEach((file) => {
-    // read file content
+    // Read file content.
     const content = fs.readFileSync(file, 'utf8');
 
     const updatedContent = content
@@ -20,7 +20,28 @@ glob('contracts/**/*.sol', null, function (err, files) {
       .replace(/onlyInitializing\s*?\{/g, 'onlyInitializingERC721A {')
       .replace(/Initializable/g, 'ERC721A__Initializable');
 
-    // write updated file
+    // Write updated file.
     fs.writeFileSync(file, updatedContent);
   });
-});
+});
+
+// Replace the TokenApprovalRef to break cyclic importing.
+let erc721aFilepath = 'contracts/ERC721AUpgradeable.sol';
+let erc721aContents = fs.readFileSync(erc721aFilepath, 'utf8');
+let tokenApprovalRefRe = /\/\/.*?\n\r?\s*struct TokenApprovalRef\s*\{[^\}]+\}/;
+let tokenApprovalRefMatch = erc721aContents.match(tokenApprovalRefRe);
+if (tokenApprovalRefMatch) {
+  erc721aContents = erc721aContents
+    .replace(tokenApprovalRefMatch[0], '')
+    .replace(/TokenApprovalRef/g, 'ERC721AStorage.TokenApprovalRef');
+  fs.writeFileSync(erc721aFilepath, erc721aContents);
+
+  let erc721aStorageFilepath = 'contracts/ERC721AStorage.sol';
+  let erc721aStorageContents = fs.readFileSync(erc721aStorageFilepath, 'utf8');
+  erc721aStorageContents = erc721aStorageContents
+    .replace(/struct Layout\s*\{/, tokenApprovalRefMatch[0] + '\n\n    struct Layout {')
+    .replace(/ERC721AUpgradeable.TokenApprovalRef/g, 'ERC721AStorage.TokenApprovalRef')
+    .replace(/import.*?\.\/ERC721AUpgradeable.sol[^;]+;/, '');
+  
+  fs.writeFileSync(erc721aStorageFilepath, erc721aStorageContents);    
+}