fix(cli): keep session reverts atomic

[marius-kilocode]

Revert currently records a conversation rewind even when an individual snapshot checkout fails. A locked or unwritable path can therefore leave only part of the workspace restored while the UI reports the entire checkpoint as reverted.

Snapshot restoration now validates checkpoint trees before mutation and treats checkout, restore, and deletion failures as fatal. Revert, replacing an existing revert, and Unrevert all run as compensated transitions: they capture a durable baseline, restore only the checkpoint patch paths through the snapshot service, and preserve both the original and rollback failure causes. Conversation state is persisted only after every affected file reaches the requested checkpoint.

Fixes #11864

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

All issues from the previous review round were addressed in this update: KiloSessionRevert.restore now delegates path/file resolution to snap.revert() (worktree-relative resolution, no more Instance.directory mismatch, and no more per-restore full-tree track()), the pre-restore step in revert() and the restore in unrevert() are now wrapped by KiloSessionRevert.apply's baseline compensation, and rollback failures are combined with Cause.combine so the original failure cause is preserved. New tests cover the replace-revert and unrevert failure paths and a nested worktree-subdirectory restore scenario.

Files Reviewed (3 files)

• packages/opencode/src/kilocode/session/revert.ts
• packages/opencode/src/session/revert.ts
• packages/opencode/test/kilocode/session/revert.test.ts

Previous Review Summary (commit 16f8e7e)

Current summary above is authoritative. Previous snapshots are kept for context only.

Previous review (commit 16f8e7e)

Status: 5 Issues Found | Recommendation: Address before merge

Overview

Severity	Count
CRITICAL	1
WARNING	3
SUGGESTION	1

Issue Details (click to expand)

CRITICAL

File	Line	Issue
packages/opencode/src/kilocode/session/revert.ts	25	Resolves worktree-relative diff paths against Instance.directory instead of Instance.worktree, which can silently skip or mis-target file deletion when they differ

WARNING

File	Line	Issue
packages/opencode/src/kilocode/session/revert.ts	22	New full-tree snap.track() call added to every restore() invocation, increasing cost of every revert/unrevert
packages/opencode/src/session/revert.ts	89	Pre-restore step (undo previous revert) has no baseline compensation on failure, unlike the new patch-apply path
packages/opencode/src/session/revert.ts	127	unrevert() restore has no compensation/rollback on partial failure, same bug class this PR fixes for revert()

SUGGESTION

File	Line	Issue
packages/opencode/src/kilocode/session/revert.ts	16	Original revert failure cause is dropped if the compensating restore also fails

Files Reviewed (5 files)

• .changeset/atomic-session-revert.md
• packages/opencode/src/kilocode/session/revert.ts - 3 issues
• packages/opencode/src/session/revert.ts - 2 issues
• packages/opencode/src/snapshot/index.ts
• packages/opencode/test/kilocode/session/revert.test.ts

Fix these issues in Kilo Cloud

---

_{Reviewed by claude-sonnet-5 · Input: 40 · Output: 19K · Cached: 1.2M}

_{Review guidance: REVIEW.md from base branch main}