[Epic] Protocol 28 - Data Team #470

Background

Protocol 28 has three CAPs under consideration (final inclusion decision expected 7/28 per the P28 timeline). This epic tracks the work needed to ensure Hubble decodes the new XDR correctly and existing models/processors don't silently break or drop data.

CAP-0083 — Vote to drop the transaction set (Accepted)
CAP-0085 — Externally managed contract executables (Final Comment Period)
CAP-0086 — Sparse map host functions (Final Comment Period; At Risk for not Making Scope)
Slack: #protocol-28

Update 7/28: CAP-0084 (muxed contract addresses) will not be ready for Protocol 28 and has been removed from this epic. It does not block crossmint/mgi (Slack announcement).

Impact summary: CAP-0083 and CAP-0086 should be no-ops (though please confirm that we don't parse the transaction set); CAP-0085 incurs minor changes with a new ContractExecutable and SCVal type.

XDR Impact

New types/arms across the three CAPs:

• StellarValueType gains STELLAR_VALUE_EMPTY_TX_SET = 2, a new ext arm on StellarValue (proposedValue struct) in LedgerHeader.scpValue (CAP-0083)
• ContractExecutableType gains CONTRACT_EXECUTABLE_EXTERNAL_REF = 2 with new ContractExecutableExternalRef struct; SCValType gains SCV_EXECUTABLE_TAG = 22 with SCString payload (CAP-0085)
• CAP-0086 has no XDR changes (new host functions only)

Primary risk: any code path that XDR-decodes LedgerCloseMeta, an SCVal, or a contract instance entry will error on the new union arms unless the SDK is bumped. Everything else is verification.

Upgrade checklist

• Confirm final CAP list after the 7/28 inclusion decision and trim this epic accordingly
• Bump and deploy go-stellar-xdr-json
• Upgrade the go-stellar-sdk version and go-stellar-xdr-json libraries in stellar-etl
• Adapt XDR transforms to support new XDR fields
• Add schema changes to stellar-dbt raw models for new fields
• Bump Galexie to use latest core stable build
• Bump dependencies in ledger data indexer
• Deploy Protocol 28 on Testnet and run stellar-etl + stellar-dbt against it — validate no processor crashes or silent data drops (testnet vote: 8/19); Deploying services includes: stellar-etl, stellar-dbt, stellar-dbt-public, Galexie, ledger-data-indexer
• Data stable release (8/11 - 8/13 per timeline, depends on Galexie + go SDK)
• Deploy to Mainnet and validate (mainnet vote: 9/9)