The bare cache used a mirror-style fetch refspec
(+refs/heads/*:refs/heads/*) which collided with worktree-locked
refs/heads/agent/<task> branches once those branches were pushed
back to origin as PRs. git fetch aborted with "refusing to fetch
into branch ... checked out at ...", the error was swallowed as a
warning, and every subsequent checkout reused the snapshot from
the original clone.
Fix:
- Clone / migrate bare caches to a remote-tracking layout
(+refs/heads/*:refs/remotes/origin/*) so fetched heads never
land in refs/heads/*.
- Resolve the base ref from refs/remotes/origin/HEAD with a
5-level fallback (verified origin/HEAD symref to origin/main
or origin/master to the bare HEAD bridged into origin/<same>
to single-entry origin/* scan to bare HEAD for legacy caches).
- Refuse to guess when refs/remotes/origin/* has multiple
candidates and none match a known fallback, so CreateWorktree
fails loudly instead of basing work on an arbitrary branch.
- Refresh refs/remotes/origin/HEAD after every successful fetch,
not just on the legacy migration path, so a cache that was
already modern picks up an upstream default-branch change.
- Verify the primary symref target actually exists so a phantom
refs/remotes/origin/HEAD from a broken set-head does not
surface a deleted branch.
- Detect legacy caches on the fly and rewrite refspec +
refs/remotes/origin/* + refs/remotes/origin/HEAD in place so
existing clones self-heal on next use.
- Serialize per-bare-repo mutation (both Sync and CreateWorktree)
with sync.Map-backed mutexes so concurrent fetch and worktree
add on the same repo cannot race on git's own lockfiles.
- Narrow the already-exists retry to actual branch-collision
errors so a path-collision no longer silently leaks a branch
into the bare repo.
Agents now decide which repo to use based on issue context and check out
repos on demand via `multica repo checkout <url>`. Workspace repos are
cached locally as bare clones for fast worktree creation.
Key changes:
- Add repocache package for bare clone management (clone, fetch, worktree)
- Add `multica repo checkout` CLI command that talks to local daemon
- Add POST /repo/checkout endpoint on daemon health server
- Pass workspace repos metadata through register + task claim responses
- Remove pre-created worktrees from execenv (workdir starts empty)
- Update CLAUDE.md template to instruct agents to use `multica repo checkout`
- Pass MULTICA_DAEMON_PORT, WORKSPACE_ID, AGENT_NAME, TASK_ID env vars to agent
