[XCM] Observability & Debuggability

[acatangiu]

Message Tracking

Make XCM messages easier to trace:

• XCM transport layers emit success and failure events containing local XCM message_id,
  • Add "Sent" event when a message is sent via execute #6851
    • Add EventEmitter to XCM Executor #7234
• Use SetTopic to set an unique global topic in all XCM programs built by FRAME or Polkadot pallets and/or System Chains runtimes,
• Make sure the "topic" is inherited by all onward XCM messages generated as a result of local execution of an XCM program,
  • Ensure Consistent Topic IDs for Traceable Cross-Chain XCM #7691
  • Enable Coretime Integration Tests & Update Changelog for SetTopic Changes polkadot-fellows/runtimes#759
• Associate XCM global topic with local message_id and emit event so that indexers can quickly triage messages and categorize them into cross-chain flows.
• All docs, examples and tests also use SetTopic in the same way,
  • Update RemoteExporter docs to reflect removal of forward_id_for #8795

Debuggability

• Emit error-specific events for XCM execution errors:
  • messageQueue not showing Error when success is no #478
  • [xcm] Investigate the possibility of ProcessXcmMessage / XcmExecutor emitting an event on failure. #2780
  • Nest errors in pallet-xcm #7730
  • [XCM] don't ignore errors #8419
    • Make WeightBounds return XcmError to surface failures #8535
• Runtime API guide/tool for replaying XCM messages with full logging on polkadot-docs, e.g. https://franciscoaguirre.github.io/polkadot-dry-runner/
  • Add Guide: Replay & Dry Run XCMs with Full Logging Using Chopsticks polkadot-developers/polkadot-docs#734
• Chopsticks guide on how to replay XCMs with full logging on polkadot-docs,
  • Add Guide: Replay XCMs with Full Logging Using Chopsticks polkadot-developers/polkadot-docs#488
    • Add Guide: Replay & Dry Run XCMs with Full Logging Using Chopsticks polkadot-developers/polkadot-docs#734
  • Related:
    • Ecosystem XCM regression tests #3097
    • Chopsticks tests for XCM #6712
    • XCM Documentation #6774
• Publish log-enabled runtime versions:
  • Publish log-enabled runtime versions #6123
  • Improve the runtime release process to include debug wasm in artifacts polkadot-fellows/runtimes#268
    • Publish debug-enabled runtimes for on-chain replaying and debugging and try-runtime testing polkadot-fellows/runtimes#767
• Log errors with target: xcm including error condition specifics and context,
  • Improve XCM debuggability  #644
  • [XCM] don't ignore errors #2408
    • xcm-builder: added logging for xcm filters/helpers/matchers/types (#2408) #7003
  • Implement detailed logging for XCM failures #8724
• Add tracing logs to all SDK-provided XCM filters, helpers, matchers and types. E.g. everything in:
  • Replace log with tracing on XCM-related modules #8732
  • https://github.com/paritytech/polkadot-sdk/blob/master/polkadot/xcm/xcm-builder/src/
  • https://github.com/paritytech/polkadot-sdk/tree/master/cumulus/parachains/runtimes/assets/common/src
  • runtime-defined XCM filters/converters (just one example)

Developer tracing

• Enable logger for all crates unit-tests:
  • Add a logger to unit tests #6125
  • Enhance XCM Debugging with Log Capture in Unit Tests #7594
  • Simplify event assertion with predicate-based check #7734

[bkontur]

* [ ]  Make sure the "topic" is inherited by all onward XCM messages generated as a result of local execution of an XCM program,

We should be able to add (or extend existing) xcm-emulated tests with SetTopic check, that initial tracking ID generated by the sender is the same on the receiver chain:

• PenpalA uses relaychain as reserve and sends to the PenpalB (or other chain)
• PenpalA uses AssetHub as reserve and sends to the PenpalB (or other chain)

[antonkhvorov]

This is super required for what we build in novasama.io