fix: decode parent block validation data after runtime upgrade

[manuelmauro]

Problem

When a block performs a runtime upgrade, getValidationData fails to decode the parent's setValidationData extrinsic. This breaks block building after any upgrade that changes the extrinsic format (e.g. the 1-arg → 2-arg change in polkadot-stable2512).

Root cause

1. buildBlock creates the upgrade block with its storageDiff containing :code:

   new Block(chain, number, hash, head, { ..., storageDiff })
   

2. In the Block constructor, #meta is first set to parentBlock.meta (the old/correct metadata), but then immediately reset because :code changed:

   this.#meta = parentBlock?.meta    // ← old metadata, correct for extrinsics
   // ...
   if (storageDiff[':code']) {
       this.#meta = undefined         // ← gone!
   }

3. Later, when building the next block, getValidationData(parent) calls parent.meta. Since #meta is undefined, the getter lazily recomputes it by calling Metadata_metadata against the block's new wasm — returning post-upgrade metadata that doesn't match the extrinsics.

Fix

Add Block.extrinsicMeta — set from parentBlock.meta in the constructor and intentionally not reset when :code changes. For remote blocks without a known parent, it falls back to fetching the parent block's metadata.

In getValidationData, replace parent.meta → parent.extrinsicMeta for extrinsic decoding.

Fixes #1003

[github-actions]

Found 1 logic issue in the extrinsic decoding process.

[ermalkaleci]

This doesn't seem like a solid solution. The issue must be elsewhere since validation data is decoded with parents metadata

[manuelmauro]

This doesn't seem like a solid solution. The issue must be elsewhere since validation data is decoded with parents metadata

Hi @ermalkaleci , thank you for your feedback! I tried a different approach.

[ermalkaleci]

It's working for your case because you're using grandparent block and it produces correct slot for your specific case. Implementation is incorrect.

[ermalkaleci]

can you provide runtime wasm so I can debug & fix it?

[manuelmauro]

Thank you! We are experiencing the problem on this PR: moonbeam-foundation/moonbeam#3633 as you can see I patched the pnpm dependency with the changes here. To reproduce it is sufficient to remove the patch then run cd tests && moonwall test upgrade_moonbase. moonbeam_runtime.wasm.zip

[ermalkaleci]

Can't perform upgrade with uncompressed wasm (15Mb)

[manuelmauro]

Can't perform upgrade with uncompressed wasm (15Mb)

Please, find the compressed one here
moonbeam_runtime.compact.compressed.wasm.zip

[ermalkaleci]

#1005 this should fix it

[manuelmauro]

Thank you! This #1005 fixed the issue. Closing this PR.