refactor: Split protocol.rs into protocol/ submodule

[2witstudios]

Summary

• Split the 2,614-line crates/pu-core/src/protocol.rs into a protocol/ directory module with 6 focused files: encoding.rs, grid.rs, targets.rs, payloads.rs, tests.rs, and mod.rs
• Pure refactoring — no behavior changes, all public API paths preserved via re-exports
• All 527 tests pass across pu-core, pu-engine, and pu-cli

Test plan

• cargo test -p pu-core — 304 tests pass
• cargo test -p pu-engine — 130 tests pass
• cargo test -p pu-cli — 93 tests pass

🤖 Generated with Claude Code

Summary by CodeRabbit

• Refactor

  • Reorganized protocol layer into modular structure for improved code organization and maintainability
  • Restructured protocol message definitions and payload structures for better clarity

• Tests

  • Expanded protocol test coverage with comprehensive serialization and deserialization validation tests

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 72b077e4-e242-46b9-ad84-a8a8535f227b

📥 Commits

Reviewing files that changed from the base of the PR and between f8db725 and 4d25306.

📒 Files selected for processing (7)

• crates/pu-core/src/protocol.rs
• crates/pu-core/src/protocol/encoding.rs
• crates/pu-core/src/protocol/grid.rs
• crates/pu-core/src/protocol/mod.rs
• crates/pu-core/src/protocol/payloads.rs
• crates/pu-core/src/protocol/targets.rs
• crates/pu-core/src/protocol/tests.rs

📝 Walkthrough

Walkthrough

The protocol layer is being reorganized from a single monolithic file (protocol.rs) into a modular structure with separate files for encoding helpers, grid commands, target types, and payload definitions. The public API surface is maintained through module re-exports and a new mod.rs that acts as the entry point.

Changes

Cohort / File(s)	Summary
Protocol Removal crates/pu-core/src/protocol.rs	Deleted entire public protocol surface (2614 lines) including Request/Response enums, payload structs, conversions, constants, and test suite.
Modular Protocol Structure crates/pu-core/src/protocol/mod.rs, crates/pu-core/src/protocol/encoding.rs, crates/pu-core/src/protocol/grid.rs, crates/pu-core/src/protocol/targets.rs, crates/pu-core/src/protocol/payloads.rs	Reorganized protocol definitions across specialized modules: mod.rs (Request/Response enums and re-exports), encoding.rs (hex serialization helpers), grid.rs (GridCommand enum), targets.rs (KillTarget/SuspendTarget enums), payloads.rs (payload structs and From trait conversions).
Test Suite crates/pu-core/src/protocol/tests.rs	Added comprehensive test coverage (1831 lines) validating JSON round-trips for all protocol messages, default values, optional fields, and various enum variants.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• feat: Event-driven trigger system for agent workflows #121 — Modifies protocol surface for triggers/gates with TriggerActionPayload, GatePayload, and TriggerInfo conversions.
• feat: Configurable agent launch args #117 — Modifies protocol surface for configuration APIs including GetConfig, UpdateAgentConfig, and AgentConfigInfo.
• Add schedule backend with CRUD, recurrence engine, and Swift UI #47 — Modifies protocol surface with schedule, grid, and template-related type changes.

Poem

🐰 The warren rejoices, no more one big file!
Protocol split into modules with style—
Encoding and grids, each tucked in their place,
Payloads and targets now have breathing space. ✨

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: a refactoring that splits a monolithic protocol.rs file into a protocol/ submodule directory with six organized files (encoding, grid, targets, payloads, tests, mod).
Docstring Coverage	✅ Passed	Docstring coverage is 90.00% which is sufficient. The required threshold is 80.00%.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch pu/refactor-protocol

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[coderabbitai]

🧹 Nitpick comments (1)

crates/pu-core/src/protocol/tests.rs (1)

482-484: Consider extracting the protocol version constant assertion.

The hardcoded value 4 here will need updating when PROTOCOL_VERSION changes. This test ensures the version is intentional, which is good, but consider adding a comment explaining why this assertion exists (to catch accidental version bumps).

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@crates/pu-core/src/protocol/tests.rs` around lines 482 - 484, The test
given_protocol_version_should_be_current currently asserts PROTOCOL_VERSION
equals the hardcoded value 4; update the test to keep the explicit assertion but
add a clarifying comment above the assertion explaining that this check is
intentional to catch accidental protocol bumps and must be manually updated when
the protocol is intentionally versioned, and optionally extract the literal into
a named test-constant (e.g., EXPECTED_PROTOCOL_VERSION) referenced in the
assertion to make intent clearer; locate this in the
given_protocol_version_should_be_current function referencing PROTOCOL_VERSION
and modify accordingly.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@crates/pu-core/src/protocol/tests.rs`:
- Around line 482-484: The test given_protocol_version_should_be_current
currently asserts PROTOCOL_VERSION equals the hardcoded value 4; update the test
to keep the explicit assertion but add a clarifying comment above the assertion
explaining that this check is intentional to catch accidental protocol bumps and
must be manually updated when the protocol is intentionally versioned, and
optionally extract the literal into a named test-constant (e.g.,
EXPECTED_PROTOCOL_VERSION) referenced in the assertion to make intent clearer;
locate this in the given_protocol_version_should_be_current function referencing
PROTOCOL_VERSION and modify accordingly.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: e71dfce7-f776-4dc2-ac87-27ac4f197ae5

📥 Commits

Reviewing files that changed from the base of the PR and between 2a876e0 and f8db725.

📒 Files selected for processing (7)

• crates/pu-core/src/protocol.rs
• crates/pu-core/src/protocol/encoding.rs
• crates/pu-core/src/protocol/grid.rs
• crates/pu-core/src/protocol/mod.rs
• crates/pu-core/src/protocol/payloads.rs
• crates/pu-core/src/protocol/targets.rs
• crates/pu-core/src/protocol/tests.rs

💤 Files with no reviewable changes (1)

• crates/pu-core/src/protocol.rs

[2witstudios]

Addressed the CodeRabbit nitpick: added a clarifying comment to the protocol version assertion in tests.rs (6eb2db6). The hardcoded check is intentional to catch accidental protocol bumps.

[2witstudios]

Rebased onto main to incorporate PR #131 (trigger opt-in). Changes applied to the submodule structure:

• protocol/mod.rs: PROTOCOL_VERSION 4→5, added trigger: Option<String> to Spawn, added AssignTrigger request variant and AssignTriggerResult response variant
• protocol/tests.rs: Added trigger: None to all Spawn test constructions, added round-trip tests for AssignTrigger and AssignTriggerResult, updated version assertion to 5

All 306 pu-core + 93 pu-cli + 130 pu-engine tests pass.