Fix: Allow appending to struct at the end of storage layout #1136 #1147

ginzahatemi · 2025-04-04T18:59:20Z

Issue

When appending fields to a struct that is at the end of a contract's storage layout, the upgrades validation incorrectly reports an incompatible layout error. This happens despite the fact that this operation is safe, as it only extends into previously unused storage space.

Fix

This PR modifies the storage layout validation logic to properly handle struct field appending when:

The struct is at the end of the storage layout
Only new fields are added (no modification to existing fields)
The fields are appended at the end of the struct

The changes include:

Added detection for when fields are only being appended to a struct
Enhanced the operation filter in layoutLevenshtein to handle struct member changes
Added appropriate documentation explaining the safety of this operation

Works With

Regular storage variables
Namespaced storage (ERC-7201)

Fixes #1136

…tructs in storage layout. Added checks for struct member changes

ericglau

Thanks for the PR.
Can you please add some tests? These should include when validations should pass, and when validations should report errors (for example, when appending at the end of a struct, but the struct is not at the end of storage).

packages/core/src/storage/compare.ts

…ludes cases for valid and invalid struct modifications, ensuring proper error handling and namespace support.

…ayoutComparator to improve code clarity and maintainability.

…ncy. Cleaned up whitespace in struct append tests for improved readability.

packages/core/src/storage/struct-append.test.ts

…mplement tests for valid and invalid struct appending scenarios in storage layout validation.

ginzahatemi · 2025-04-10T04:20:30Z

Hi @ericglau ,

I have implemented the changes based on your suggestions. Could you please review them at your convenience? If everything looks good, would you mind proceeding with the merge?

Thank you!

ericglau

I've adjusted the test cases for the second scenario to properly demonstrate insertion before the end of storage layout.

However, the first test case is still failing with the following operations even though it should have been filtered out by the new code in compare.ts:

 [
    {
      "kind": "typechange",
      "change": {
        "kind": "struct members",
        "ops": [
          {
            "kind": "append",
            "totalCost": 0,
            "predecessor": {
              "kind": "nop",
              "totalCost": 0,
              "predecessor": {
                "kind": "nop",
                "totalCost": 0,
                "predecessor": {
                  "kind": "nop",
                  "totalCost": 0
                }
              }
            },
            "updated": {
              "label": "z",
              "type": {
                "id": "t_uint256",
                "head": "t_uint256",
                "item": {
                  "label": "uint256",
                  "numberOfBytes": "32"
                }
              },
              "offset": 0,
              "slot": "2"
            }
          }
        ],
...

The logic for the comparison may need to be investigated or this may need further debugging.

ericglau · 2025-04-11T21:49:43Z

packages/core/contracts/test/StructAppend.sol

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;


This is missing test cases for namespaced structs as described in #1136

I've added test cases for namespaced structs as requested in the latest commit. Let me know if there are any more suggestions

…tructs in storage layout. Added checks for struct member changes

…ludes cases for valid and invalid struct modifications, ensuring proper error handling and namespace support.

…ayoutComparator to improve code clarity and maintainability.

…ncy. Cleaned up whitespace in struct append tests for improved readability.

…mplement tests for valid and invalid struct appending scenarios in storage layout validation.

…penzeppelin-upgrades into struct-append-1136

ginzahatemi · 2025-04-22T10:45:46Z

Hey @ericglau I have made the suggested changes and pushed some commit, could you review them, if they are Ok or not?

…logic.

ginzahatemi · 2025-05-02T10:48:52Z

hey @ericglau its been a week almost. Would you review if the commits are ok ? and If it is can you merge the PR ?

ericglau

Sorry for the late response, but the new commits don't address my previous comments. The testcase failure still occurs, and namespaced test cases have not been added.

This section of code is in a critical part of the validation logic, and needs to be carefully considered for quality and fully tested with both positive and negative tests.

The changes proposed here aren't succinct and it does not fix the originally described issue, as demonstrated by the failing test case.

Thanks for your efforts, but due to the above, I would suggest to either close this PR or it can be revisited at a later time.

ericglau · 2025-05-02T15:23:30Z

packages/core/src/storage/compare.ts

+        const structEnd = storageFieldEnd(o.original);
+        if (structEnd === undefined) {
+          return true;
+        }
+
+        const hasFieldsAfter = original
+          .filter(field => !isGap(field))
+          .some(field => {
+            const fieldStart = storageFieldBegin(field);
+            if (field === o.original || fieldStart === undefined) {
+              return false;
+            }
+            return fieldStart > structEnd;
+          });
+
+        return hasFieldsAfter;


It's not clear what this section of code achieves. There should be testcases and changing/removing any of this code should cause those testcases to fail.

Enhance StorageLayoutComparator to safely allow appending fields to s…

28e7838

…tructs in storage layout. Added checks for struct member changes

ginzahatemi mentioned this pull request Apr 4, 2025

Cannot append to struct at the end of storage layout #1136

Open

ericglau reviewed Apr 4, 2025

View reviewed changes

packages/core/src/storage/compare.ts Outdated Show resolved Hide resolved

ginzahatemi added 3 commits April 5, 2025 13:32

Add unit tests for struct appending in storage layout validation. Inc…

f1ac5fd

…ludes cases for valid and invalid struct modifications, ensuring proper error handling and namespace support.

Remove outdated comments regarding struct field appending in StorageL…

27c92d8

…ayoutComparator to improve code clarity and maintainability.

Refactor comments in StorageLayoutComparator for clarity and consiste…

118adb3

…ncy. Cleaned up whitespace in struct append tests for improved readability.

ericglau reviewed Apr 7, 2025

View reviewed changes

packages/core/src/storage/struct-append.test.ts Outdated Show resolved Hide resolved

Add StructAppend contract with versioning for struct modifications. I…

f0bf093

…mplement tests for valid and invalid struct appending scenarios in storage layout validation.

Fix testcases

a59deba

ericglau reviewed Apr 11, 2025

View reviewed changes

ginzahatemi added 7 commits April 15, 2025 05:43

Enhance StorageLayoutComparator to safely allow appending fields to s…

30874ce

…tructs in storage layout. Added checks for struct member changes

Add unit tests for struct appending in storage layout validation. Inc…

59fcbf7

…ludes cases for valid and invalid struct modifications, ensuring proper error handling and namespace support.

Remove outdated comments regarding struct field appending in StorageL…

00b0d43

…ayoutComparator to improve code clarity and maintainability.

Refactor comments in StorageLayoutComparator for clarity and consiste…

cf214a8

…ncy. Cleaned up whitespace in struct append tests for improved readability.

Add StructAppend contract with versioning for struct modifications. I…

7fb9ba9

…mplement tests for valid and invalid struct appending scenarios in storage layout validation.

Merge branch 'OpenZeppelin:master' into struct-append-1136

59f7477

Merge branch 'struct-append-1136' of https://github.com/ginzahatemi/o…

a53fcf5

…penzeppelin-upgrades into struct-append-1136

ginzahatemi force-pushed the struct-append-1136 branch 2 times, most recently from 1c682de to a53fcf5 Compare April 29, 2025 08:51

Refactor StorageLayoutComparator to improve struct append validation …

d7a3aa9

…logic.

ericglau reviewed May 2, 2025

View reviewed changes

ginzahatemi closed this May 28, 2025

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Fix: Allow appending to struct at the end of storage layout #1136 #1147

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		@@ -0,0 +1,42 @@
		// SPDX-License-Identifier: MIT
		pragma solidity ^0.8.0;

Fix: Allow appending to struct at the end of storage layout #1136 #1147

Fix: Allow appending to struct at the end of storage layout #1136 #1147

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ginzahatemi commented Apr 4, 2025

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