Argument-0008: Retention at Rank 2

Report Date	Date of submission (2026/03/25)
Submitted by	Christian Langenbacher

Member details

• Matrix username: @clang:matrix.org
• Polkadot address: 16YCL3UVpVWQLGW3p3Zx4k5WAEp9W1DwdDnxAbyAaPxVxnp3
• Current rank: 2
• Date of initial induction: 2024/03/27
• Date of last report: 2026/01/10
• Area(s) of Expertise/Interest: Parachain Builder, Runtime, Clients

Reporting period

• Start date: 2026/01/10
• End date: 2026/03/25

Argument

My argument primarily revolves around PRs and issues that I filed in the Polkadot SDK and Runtimes repositories. Additionally, I was quite active in Element chats, helping community members with technical questions.

Finalize - Revamp of Penpal Asset Management and XCM Fee Payment

I have already mentioned the PR in the last report. As per the review, I have also added a GenesisConfig struct to the pallet-asset-conversion. This further simplifies the setup for the emulated integration tests, which will also be used in an upcoming PR, applying the same changes into the emulated tests in the runtimes repository.

Additionally, while working on this PR, which made the tests more production-realistic, I have identified and fixed a bug in the SwapFirstAssetTrader. When the fees were exact, Fungible(0) was put into the holding register. This resulted in an AssetTrapped(Fungible(0)) event that failed to decode. While harmless, this resulted in event decoding errors for frontends that use the Rust code, as Fungible(0) failed to decode.

NPoS: Expose election round (priority) in ElectionResult winners

I have patched offline-election-tool to also display the priority of the winners in the election results. However, this patch required a PSDK patch to expose the validator priorities that were already computed in seq_phragmen and phragmms, but then discarded. I have upstreamed the change so that other projects can directly use the Rust implementation to compute the priorities. I have prepared a follow-up PR so that the mining functions do the same, but it needs further refinement.

Additional smaller contributions

Identify and fix slot-based collator panic (Observed on AHP)

When a parachain collator started with --authoring=slot-based and warp-synced from scratch, it panicked and shut down the node as it did not properly wait for aura to be ready. I identified this at a sys-collator I support and fixed it with the same mechanism that we use for the lookahead collators.

Pallet Assets: Properly decrement supply during refund if asset is burned

When a user called refund with allow_burn = true, their token balance was destroyed, but the asset's total supply was never updated. This caused total issuance to be overcounted. In production, the burning path was rarely triggered. The fungibles trait interface always passed allow_burn = false, so only users manually submitting the refund extrinsic with the burn flag would hit it; however, it was observed on Westend. It will need a migration there to correct the total issuance, but I have at least fixed the root cause.

Voting record

Ranks	Activity thresholds	Agreement thresholds	Member's voting activities	Comments
I	90%	N/A
II	80%	N/A	No eligible referenda
III	70%	100%
IV	60%	90%
V	50%	80%
VI	40%	70%

Misc

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