fix: Re-add node version to Handshake completed

[dknopik]

Issue Addressed

In rc.1, we (accidentally?) removed logging the node version after a completed handshake.

Proposed Changes

This info is very useful for debugging, e.g. if we see repeated invalid messages from a certain peer and we want to know what software sent those messages. This PR readds the field.

[claude-code-actions-sigp]

Claude finished @dknopik's task —— View job

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Code Review Complete

Todo List

• Read the modified file to understand the context
• Review the changes against base branch
• Analyze code quality, security, performance, testing, and documentation
• Provide comprehensive feedback

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Summary

This PR re-adds the node_version field to the debug log statement after a successful handshake. The change is simple, focused, and addresses the stated issue effectively.

Review Findings

Code Quality ✅

• Clean and minimal: The change adds exactly one field to an existing structured logging statement
• Consistent with existing code: Follows the same pattern as other fields (our_subnets, their_subnets, matching_subnets)
• Proper formatting: Uses the % format specifier for structured logging, consistent with tracing/slog patterns

Security ✅

• No security concerns: Logging node version information is safe and commonly used for debugging
• No sensitive data exposure: Node version is public metadata already exchanged during handshake

Performance ✅

• Negligible impact: Adding one field to an existing debug log has no measurable performance impact
• Debug-level logging: This only executes when debug logging is enabled and after successful handshake (not in hot path)

Context and Design

The change is in the record_handshake_subnet_match_metrics() method at anchor/network/src/network.rs:583. This method is called after a successful handshake to:

1. Count matching subnets between local and remote peers
2. Log handshake completion details for debugging
3. Record metrics about subnet matches

The node_version field is already available in their_metadata.node_version (from NodeMetadata struct) and was previously logged before rc.1. This PR correctly restores that field.

Testing Considerations ⚠️

While the change itself is correct, there are no tests for this logging behavior. Consider:

• The logging occurs in production code path (record_handshake_subnet_match_metrics)
• There are no unit tests verifying the log output format
• This is typical for logging code, but structured log assertions could be valuable

Recommendation: Not blocking for this PR, but consider adding integration tests that verify handshake logging behavior in the future, especially for critical debugging information.

Documentation ✅

• Clear PR description: The rationale (useful for debugging invalid messages) is well explained
• Self-documenting code: The field name node_version is clear and matches the struct field name

Recommendation

Approve - This is a straightforward fix that restores useful debugging information. The change is:

• Minimal and focused
• Low risk
• Valuable for operational debugging
• Consistent with existing patterns

No changes needed before merge.

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[jking-aus]

yep