Multi branch indexing

[sashalevin]

Enables indexing and querying across multiple git branches.

The indexer accepts --branches to index several branches at once.

The query tool and MCP server accept a branch parameter to scope queries to a specific branch.

New REPL commands (branches, branch, compare) and MCP tools (list_branches, compare_branches) provide branch management.

The LSP server supports a target_branch configuration option.

[masoncl]

Seems pretty reasonable, I'll look harder this week. Can I ask for some documentation updates with how you're using it? Especially for the table that tracks what has already been indexed, I'm curious how you're using that part.

Also, you can use https://github.com/masoncl/semcode-devel if you'd prefer to use DCO instead of the CLA.

[sashalevin]

Added some docs. In general, I use it for both autosel and the cve_classifier: in the case of autosel it helps identify how far a backport should go, and the range of affected kernels for cve assignments.

The --update-branches makes it easy to keep multiple stable branches up to date as new stable kernels are released.

[masoncl]

The docs are great thank you, I can see how this would be really useful.

The changes looked good to me, claude found a few potential issues. Also, reading the docs I think you want an option to just reindex all the branches that have changed?

The only problem I really care about below is the db manager per branch, but I'll let you decide for the others.

Also, I think the semcode br
Issue 5: Initial Branch Indexing Range Bug
// index.rs:529-530
info!("Initial indexing for branch {}", branch_name);
format!("{}^..{}", tip_commit, tip_commit) // ⚠️ Only indexes 1 commit!
For initial branch indexing, this only indexes the tip commit itself, not the full branch
history. The comment says "Full indexing: index entire branch history" but the code only does
TIP^..TIP which is just the single commit.

Recommendation: For initial indexing, consider using --git flag behavior or a configurable
depth.

Issue 6: Remote Detection Logic
// index.rs:582-586
let remote = if branch_name.contains('/') {
branch_name.split('/').next()
} else {
None
};
This incorrectly marks feature/my-feature as a remote branch with remote name "feature". Should
check if it starts with a known remote name or use the is_remote flag from list_branches.

Issue 7: Creates New DatabaseManager Per Branch
// index.rs:557-561
let db_manager_arc = Arc::new(
DatabaseManager::new(&database_path, args.source.to_string_lossy().to_string())
.await?,
);
Inside the branch loop, a new DatabaseManager is created for each branch. This is inefficient
and could cause connection pool issues. Should reuse the outer db_manager.