loki/docs/implementation/PHASE-1-STEP-8g-NOTES.md

Phase 1 Step 8g — Implementation Notes

Status

Done.

Plan reference

• Plan: docs/PHASE-1-IMPLEMENTATION-PLAN.md
• Section: "Step 8g: REPL rewrite — repl/mod.rs"

Summary

Rewrote src/repl/mod.rs to thread RequestContext through run_repl_command and ask alongside the existing GlobalConfig. The Repl struct now owns both a RequestContext (source of truth for runtime state) and a GlobalConfig (read-only view for reedline components: prompt, completer, highlighter). Bidirectional sync helpers keep them in lockstep after mutations.

Also updated src/main.rs to pass RequestContext into Repl::init and src/config/macros.rs to construct a temporary RequestContext for run_repl_command calls from macro execution.

What was changed

Files modified (5 files)

• src/repl/mod.rs — major rewrite:

  • Repl struct: added ctx: RequestContext field
  • Repl::init: takes RequestContext (by value), builds GlobalConfig from ctx.to_global_config() for reedline
  • Repl::run: passes both &self.config and &mut self.ctx to run_repl_command
  • run_repl_command: signature changed to (config, ctx, abort_signal, line) -> Result<bool>. Command handlers use ctx.* methods where available, fall through to config.* for unmigrated operations. Sync helpers called after mutations.
  • ask: signature changed to (config, ctx, abort_signal, input, with_embeddings) -> Result<()>. Uses ctx.before_chat_completion, ctx.after_chat_completion. Keeps Config::compress_session, Config::maybe_compress_session, Config::maybe_autoname_session on the GlobalConfig path (they spawn tasks).
  • Added sync_ctx_to_config and sync_config_to_ctx helpers for bidirectional state synchronization.

• src/main.rs — start_interactive takes RequestContext by value, passes it into Repl::init. The run() function's REPL branch moves ctx into start_interactive.

• src/config/macros.rs — macro_execute constructs a temporary AppState + RequestContext from the GlobalConfig to satisfy run_repl_command's new signature.

• src/config/mod.rs — #[allow(dead_code)] annotations on additional methods that became dead after the REPL migration.

• src/config/bridge.rs — minor adjustments for compatibility.

Files NOT changed

• src/repl/completer.rs — still holds GlobalConfig (owned by reedline's Box<dyn Completer>)
• src/repl/prompt.rs — still holds GlobalConfig (owned by reedline's prompt system)
• src/repl/highlighter.rs — still holds GlobalConfig

Key decisions

1. Dual-ownership pattern (GlobalConfig + RequestContext)

The reedline library takes ownership of Completer, Prompt, and Highlighter as trait objects. These implement reedline traits and need to read config state (current role, session, model) to render prompts and generate completions. They can't hold &RequestContext because their lifetime is tied to Reedline, not to the REPL turn.

Solution: Repl holds both types. RequestContext is the source of truth. After each mutation on ctx, sync_ctx_to_config copies runtime fields to the GlobalConfig so the reedline components see the updates. After operations that mutate the GlobalConfig (escape hatch paths like Config::use_agent), sync_config_to_ctx copies back.

2. .exit role/session/agent keep the MCP reinit on GlobalConfig path

The .exit role, .exit session, and .exit agent handlers do McpRegistry::reinit which takes the registry out of Config, reinits it, and puts it back. This pattern requires GlobalConfig and can't use RequestContext::rebuild_tool_scope without a larger refactor. These handlers stay on the GlobalConfig path with sync-back.

3. macro_execute builds a temporary RequestContext

macro_execute in config/macros.rs calls run_repl_command which now requires &mut RequestContext. Since macro_execute receives &GlobalConfig, it constructs a temporary AppState + RequestContext from it. This is a bridge-window artifact — macro execution within the REPL creates an isolated RequestContext that doesn't persist state back.

4. ask's auto-continuation and compression stay on GlobalConfig

The auto-continuation loop and session compression in ask use Config::maybe_compress_session, Config::compress_session, and Config::maybe_autoname_session which spawn tasks and need the GlobalConfig. These stay on the old path with sync-back after completion.

Deviations from plan

Deviation	Rationale
ReplCompleter/ReplPrompt not changed to RequestContext	reedline owns them as trait objects; need shared GlobalConfig
.exit * MCP reinit on GlobalConfig path	McpRegistry::reinit pattern requires GlobalConfig
Bidirectional sync helpers added	Bridge necessity for dual-ownership
macro_execute builds temporary RequestContext	run_repl_command signature requires it

Verification

Compilation

• cargo check — clean, zero warnings, zero errors
• cargo clippy — clean

Tests

• cargo test — 63 passed, 0 failed (unchanged)

Handoff to next steps

Phase 1 Step 8 is now complete

All sub-steps 8a through 8g (plus 8h first pass) are done:

• 8a: Model::retrieve_model → &AppConfig
• 8b: Mixed-method migrations (retrieve_role, set_model, etc.)
• 8c: McpFactory::acquire extracted from McpRegistry
• 8d: Scope transitions (use_role, use_session, exit_agent)
• 8e: Session lifecycle + apply_prelude
• 8f: main.rs rewrite
• 8g: REPL rewrite
• 8h: Bridge wrappers for leaf dependencies

What Steps 9-10 need to do

Step 9: Remove the bridge

• Delete Config::from_parts, Config::to_app_config, Config::to_request_context
• Rewrite Input to hold &AppConfig + &RequestContext instead of GlobalConfig
• Rewrite Rag to take &AppConfig instead of &GlobalConfig
• Rewrite Agent::init to take &AppState + &mut RequestContext
• Eliminate to_global_config() escape hatches
• Eliminate sync_ctx_to_config/sync_config_to_ctx helpers
• Rewrite ReplCompleter/ReplPrompt to use RequestContext (requires reedline component redesign)

Step 10: Delete Config

• Remove Config struct and GlobalConfig type alias
• Remove bridge.rs module
• Remove all #[allow(dead_code)] annotations on Config methods
• Delete the _safely wrappers

Files to re-read at the start of Step 9

• docs/PHASE-1-IMPLEMENTATION-PLAN.md — Steps 9-10
• This notes file
• src/config/mod.rs — remaining Config methods
• src/config/bridge.rs — bridge conversions to delete
• src/config/input.rs — Input struct (holds GlobalConfig)
• src/rag/mod.rs — Rag struct (holds GlobalConfig)

References

• Phase 1 plan: docs/PHASE-1-IMPLEMENTATION-PLAN.md
• Step 8f notes: docs/implementation/PHASE-1-STEP-8f-NOTES.md
• Step 8h notes: docs/implementation/PHASE-1-STEP-8h-NOTES.md
• Modified files:
  • src/repl/mod.rs (major rewrite — sync helpers, dual ownership)
  • src/main.rs (start_interactive signature change)
  • src/config/macros.rs (temporary RequestContext construction)
  • src/config/mod.rs (dead_code annotations)
  • src/config/bridge.rs (compatibility adjustments)