fix(common): fix memory corruption for dynamic to static array conver…

…sion (#1598) Co-authored-by: alvarius <[email protected]>
latticexyz · Sep 25, 2023 · c4f4924 · c4f4924
1 parent 5741d53
commit c4f4924
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diff --git a/.changeset/violet-insects-press.md b/.changeset/violet-insects-press.md
@@ -0,0 +1,6 @@
+---
+"@latticexyz/cli": patch
+"@latticexyz/common": patch
+---
+
+Table libraries now correctly handle uninitialized fixed length arrays.
diff --git a/packages/cli/contracts/src/codegen/tables/Dynamics1.sol b/packages/cli/contracts/src/codegen/tables/Dynamics1.sol
diff --git a/packages/cli/contracts/src/codegen/tables/Singleton.sol b/packages/cli/contracts/src/codegen/tables/Singleton.sol
diff --git a/packages/common/src/codegen/render-solidity/renderTypeHelpers.ts b/packages/common/src/codegen/render-solidity/renderTypeHelpers.ts
@@ -63,9 +63,15 @@ function renderWrapperStaticArray(
     ) pure returns (
       ${elementType}[${staticLength}] memory _result
     ) {
-      // in memory static arrays are just dynamic arrays without the length byte
-      assembly {
-        _result := add(_value, 0x20)
+      if (_value.length < ${staticLength}) {
+        // return an uninitialized array if the length is smaller than the fixed length to avoid memory corruption
+        return _result;
+      } else {
+        // in memory static arrays are just dynamic arrays without the length byte
+        // (without the length check this could lead to memory corruption)
+        assembly {
+          _result := add(_value, 0x20)
+        }
       }
     }
   `;