Extensions re-org

[jamesadevine]

/plan Extensions is a single file with many hundreds of lines. We should separate impls into their own files and export extensions as a module.

[github-actions]

✅ Issue Plan Maker completed successfully!

[github-actions]

Implementation Plan: Extensions Module Re-org

Objective

Split src/compile/extensions.rs (~1,200 lines) into a proper Rust module directory (src/compile/extensions/) with one file per logical concern, keeping all public APIs stable.

---

Scope

In scope:

• Convert extensions.rs → extensions/mod.rs + per-concern subfiles
• Preserve all existing public paths (super::extensions::* used by common.rs, standalone.rs, onees.rs)
• Move tests to appropriate subfiles or keep consolidated in mod.rs

Out of scope:

• Renaming any public types or functions
• Changing extension behaviour or logic
• Moving runtimes/lean.rs (it stays; LeanExtension wraps it)
• Changing callers (common.rs, standalone.rs, onees.rs)

---

Proposed File Layout

src/compile/extensions/
├── mod.rs          # trait, enum macro, Extension enum, collect_*, wrap_prompt_append, tests, re-exports
├── mcpg.rs         # McpgServerConfig, McpgGatewayConfig, McpgConfig
├── context.rs      # CompileContext + CompileContext::new()
├── lean.rs         # LeanExtension + impl CompilerExtension (lines 382–448)
├── azure_devops.rs # AzureDevOpsExtension, AdoAuthMode + impl (lines 459–643, largest ~185 lines)
├── cache_memory.rs # CacheMemoryExtension + generate_memory_download (lines 644–727)
└── internal.rs     # GitHubExtension + SafeOutputsExtension (always-on, lines 735–808)

mod.rs keeps: ExtensionPhase, PipelineEnvMapping, CompilerExtension trait, extension_enum! macro, Extension enum, collect_extensions[_with_auth], wrap_prompt_append, and the existing test block. It re-exports everything so callers are unaffected.

---

Work Breakdown

• 1. Create extensions/ directory — mkdir src/compile/extensions
• 2. Extract MCPG types → mcpg.rs — move McpgServerConfig, McpgGatewayConfig, McpgConfig; add pub use in mod.rs
• 3. Extract compile context → context.rs — move CompileContext struct + impl; add pub use in mod.rs
• 4. Extract LeanExtension → lean.rs — move struct, impl LeanExtension, impl CompilerExtension for LeanExtension; adjust local use statements
• 5. Extract AzureDevOpsExtension → azure_devops.rs — move struct, AdoAuthMode, impl AzureDevOpsExtension, impl CompilerExtension; adjust imports (allowed_hosts, common consts, types)
• 6. Extract CacheMemoryExtension → cache_memory.rs — move struct, impls, generate_memory_download()
• 7. Extract always-on internals → internal.rs — move GitHubExtension + SafeOutputsExtension and their impls
• 8. Update mod.rs — declare pub(super) mod mcpg; pub(super) mod context; ... (or pub mod if needed externally); consolidate pub use re-exports; keep ExtensionPhase, PipelineEnvMapping, CompilerExtension, extension_enum!, Extension enum, collect_*, wrap_prompt_append, and tests in place
• 9. Verify build — cargo build must pass with zero warnings
• 10. Verify tests — cargo test must pass (especially extensions::tests::*)

---

Validation Strategy

cargo build            # No errors or new warnings
cargo test             # All existing tests pass
cargo clippy           # No new lints (unused imports, dead code)

Callers in common.rs, standalone.rs, and onees.rs use super::extensions::* — no changes needed there as long as all types are re-exported from mod.rs.

---

Risks and Mitigations

Risk	Mitigation
Import cycles between subfiles	mcpg.rs and context.rs have no cross-deps; lean/ado/cache only import from mcpg and context via super::
use statements scattered throughout the single file are per-section	When splitting, move each use to the file that needs it; duplicate where necessary
extension_enum! macro must see all variant types	Keep macro + Extension enum declaration in mod.rs where all submodules are in scope
Tests use use super::* and exercise multiple impls	Keep test block in mod.rs to avoid splitting test helpers; individual impls can add their own #[cfg(test)] blocks later

---

Dependencies and Assumptions

• No open PRs currently touching extensions.rs (check before starting to avoid conflicts)
• cargo fmt should be run after each extraction step to keep style consistent with the project
• Submodule visibility: use pub(super) for types only needed within compile/; use pub only for types referenced from outside compile/ (currently McpgServerConfig, McpgConfig, CompileContext, Extension, collect_extensions*, wrap_prompt_append, AdoAuthMode)

Generated by Issue Plan Maker for issue #281 · ● 438.8K · ◷