kandev/docs/specs/platform/workspace-git-status.md

status, created, owner

status	created	owner
shipped	2026-07-19	kandev

Workspace Git Status

Why

Users opening or focusing Changes and Review need a current workspace snapshot without a large generated or untracked tree monopolizing agentctl. Repeated requests for the same repository must not amplify expensive Git and filesystem work, and the initial session-hydration path must remain within its two-second live-status budget by falling back when necessary.

What

• Cached reads return the latest workspace-tracker snapshot. When no cached snapshot exists, the tracker performs a live observation.
• Fresh reads observe the live worktree and do not themselves replace the polling cache.
• Overlapping live observations for the same repository share one underlying observation. Different repositories in a multi-repository task may still be observed in parallel.
• Every non-cancelled caller receives the same completed snapshot or error from a shared observation. A caller whose own context is cancelled returns promptly without cancelling or otherwise poisoning the result for other callers.
• Tracker shutdown or the bounded shared-observation deadline cancels the underlying work. Cancelled work does not publish or cache a partial snapshot.
• After Git output is parsed, changed-file and synthetic untracked-diff enrichment performs work proportional to the number of changed entries plus the bounded content processed.
• Existing diff limits remain in force: 10 MiB maximum source file size, 256 KiB maximum emitted diff per file, and a 2 MiB enrichment threshold per status snapshot. Because the threshold is checked before enriching each file, the final accepted file may preserve the existing overshoot of up to the 256 KiB per-file cap. Existing skip reasons remain unchanged.
• Large changed sets retain every path and its status metadata. Once the total diff budget is exhausted, files that are not enriched retain budget_exceeded as their diff skip reason.
• Multi-repository responses retain repository identity and partial-success behavior.
• Verification tooling preserves shared managed Go and lint caches for reuse while keeping invocation scratch and command output outside repository worktrees. The root-level .verify-cache and .tmp paths are ignored as safeguards against legacy or misconfigured verification runs.

Base-commit staleness and refresh

The commits panel (git log <base>..HEAD) and cumulative diff anchor to a base commit derived from the session's stored base_commit_sha and base_branch. That anchor becomes stale when the branch history moves relative to the true integration branch after the base was recorded — most commonly a stacked-PR parent that merges and disappears, a rebase onto the integration branch, or a base branch that was deleted upstream. When the anchor is stale, the panel enumerates commits that are not part of the branch's own contribution, inflating the count.

• A stored base commit SHALL be treated as stale when it is a strict ancestor of the true merge-base between HEAD and the resolved integration candidate — the first branch that resolves through the priority list origin/main → origin/master → main → master. When merge-base(HEAD, <resolved integration candidate>) advances past the stored base_commit_sha, the stored base is stale. A stored base that equals or is a descendant of that merge-base is NOT stale.
• Staleness correction SHALL be limited to comparison targets that are not a live non-default upstream branch. The resolved default integration target (main/master, or its origin/* form) remains subject to the normal stale-base check. When the target IS a live non-default upstream branch (for example a feature comparing against origin/develop that has merged newer origin/main commits), its own merge-base is authoritative and SHALL NOT be overridden merely because it is an ancestor of the integration merge-base — doing so would hide commits that are genuinely part of that comparison.
• When the stored base is stale, commit enumeration and cumulative diff SHALL use the freshly computed merge-base against the resolved integration candidate instead of the stored SHA. The panel therefore reflects only the commits the branch actually introduces over the integration branch.
• Base resolution SHALL prefer the upstream integration ref (origin/<name>) over a bare local ref of the same name. A local ref that no longer tracks any live upstream (for example a merged/deleted stacked-parent branch that lingers only as a local ref) SHALL NOT anchor the commit range when an upstream integration ref is available.
• Staleness detection is a read-time correction: it changes which base the commits/diff are computed against. It does not by itself rewrite the persisted base_commit_sha; the persisted value continues to follow the existing capture and the "Compare against" base-branch reset paths.
• When neither an upstream integration ref nor a usable merge-base can be resolved (unrelated histories, offline mirror with no origin/*), behavior falls back to the existing stored-base / branch-tip anchor and the panel is unchanged from today.

API surface

No route or payload shape changes.

• GET /api/v1/git/status?repo=<subpath>&fresh=<bool> returns the existing GitStatusResult shape.
• GET /api/v1/git/status/multi?fresh=<bool> returns the existing MultiRepoGitStatusResult shape containing PerRepoGitStatus entries.
• The fresh query parameter continues to select a live observation rather than a cached tracker snapshot.

Failure modes

Scenario	Observable behavior
Primary branch or porcelain observation fails	The live observation fails and the prior cached snapshot remains available.
Secondary diff enrichment fails	The established same-HEAD carry-forward behavior is preserved.
One caller cancels while a shared observation is running	That caller returns its context cancellation promptly; other callers remain eligible to receive the shared result.
The tracker stops or the shared deadline expires	Underlying work is cancelled and no partial result is published or cached.
One repository fails during a multi-repository request	Successful repository entries remain available and the failure is reported on its repository entry.
Stored base commit is a strict ancestor of merge-base(HEAD, <resolved integration candidate>) and the target is not a live non-default upstream branch	Commit enumeration and cumulative diff use the freshly computed merge-base, not the stale stored SHA; the count reflects only the branch's own commits.
Comparison target is a live non-default upstream branch (e.g. origin/develop) whose merge-base is an ancestor of the integration merge-base	The target's own merge-base is preserved; the range is NOT re-anchored to the integration line.
Resolved base branch exists only as a stale local ref (upstream merged/deleted) but an integration origin/* ref is present	The origin/* integration ref anchors the range; the stale local ref does not.
No origin/* integration ref and no usable merge-base (unrelated histories)	Falls back to the existing stored-base / branch-tip anchor; behavior is unchanged from today.

Scenarios

• GIVEN a stale cached snapshot after a commit, WHEN a caller requests fresh=true, THEN the response reflects the live clean tree and a later cached read still returns the prior cached snapshot.
• GIVEN six simultaneous fresh requests for one repository, WHEN their observations overlap, THEN exactly one underlying status observation runs and all non-cancelled callers receive the same capture timestamp and result.
• GIVEN simultaneous fresh requests for two repositories, WHEN multi-repository status runs, THEN one observation per repository may run in parallel and each response remains identified with its repository.
• GIVEN one waiter cancels during a shared observation, WHEN other waiters remain, THEN the cancelled waiter returns promptly and the remaining waiters receive the completed result.
• GIVEN tracker shutdown or the shared-observation deadline while enrichment is running, WHEN cancellation reaches the observation, THEN filesystem iteration stops and no partial snapshot is cached.
• GIVEN approximately 15,000 untracked text files, WHEN fresh status is computed, THEN every path is present, emitted diff content obeys the existing limits, files not enriched after total-budget exhaustion have budget_exceeded, and post-porcelain enrichment remains linear in the number of entries.
• GIVEN one invalid repository in a multi-repository request, WHEN other repositories succeed, THEN the response retains the successful entries and reports the failure only on the invalid repository.
• GIVEN verification needs writable scratch space, WHEN it selects a location, THEN the location is outside every Git worktree and existing shared caches remain reusable; if a legacy run creates root-level .verify-cache or .tmp, Git status ignores it.
• GIVEN a session whose stored base_commit_sha is a strict ancestor of merge-base(HEAD, <resolved integration candidate>) (for example a stacked-PR parent branch that has since merged into the integration branch and lost its upstream ref), WHEN the commits panel is requested, THEN the enumerated commit count matches git rev-list --first-parent --count $(git merge-base HEAD <resolved integration candidate>)..HEAD and excludes the commits that already landed on the integration branch.
• GIVEN a stored base branch that no longer has an upstream ref (the remote branch was deleted) but a local ref of the same name still points at an old branch point, WHEN the commits panel resolves its base, THEN it anchors to the merge-base against the origin/main/origin/master integration ref rather than the stale local ref.
• GIVEN a session whose stored base_commit_sha equals or is a descendant of the current merge-base against the integration branch, WHEN the commits panel is requested, THEN the stored base is used unchanged and the count is identical to today's behavior.
• GIVEN a session comparing against a live non-default upstream branch (for example origin/develop) whose merge-base is a strict ancestor of the integration merge-base, WHEN the commits panel resolves its base, THEN it keeps the develop merge-base and does not re-anchor to the integration line, so commits genuinely part of the develop comparison remain visible.
• GIVEN a worktree with no origin/* integration ref and a HEAD sharing no history with any candidate branch, WHEN the commits panel resolves its base, THEN it falls back to the existing stored-base / branch-tip anchor and does not error.

Out of scope

• Changing Git-status API routes, response shapes, or frontend rendering.
• Raising or removing existing diff-content limits.
• Changing multi-repository fan-out behavior.
• Making fresh reads owners of the polling cache.
• Replacing Git subprocesses with a native Git implementation.
• Rewriting the persisted base_commit_sha as part of staleness detection. The read-time correction changes only which base the commits/diff compute against; persistence continues to follow the existing capture and "Compare against" reset paths.
• Auto-retargeting the session's base_branch when a stacked parent merges. Detecting a stale base and picking a live integration ref is in scope; changing the stored base branch is not.

Implementation plan

See Workspace Git Status Scalability plan.