Reverting a message restores the whole worktree and discards other sessions' uncommitted changes #54026

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1. github-actions

   assigned

   nexxeln

   on Oct 8, 2026
2. opencode-agent commented on Oct 8, 2026

   

   opencode-agentbot

   on Oct 8, 2026 – with OpenCode Agent

   Contributor

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   Thanks for the detailed report. I was able to reproduce this on 2.0.23, and it still happens on the latest v2 (b5c43a44).

   What I ran (script below):

   1. A session runs a step that only calls a read-only shell command (ls).
   2. While that step is running, something else (here a separate writer standing in for your Session A) changes a tracked file and creates a new file in the same worktree.
   3. Reverting the message through POST /session/:id/revert/stage, with no files (the same call the web UI makes), puts the edited file back to its old content and deletes the new file, with no warning.

   The revert isn't restoring the whole worktree. It only restores the files recorded for each step. The problem is that this file list comes from comparing snapshots of the whole worktree taken at the start and end of the step, so anything another session changed during that step gets counted as this session's change and is then rolled back.

   Related issues:

   • v2: redesign filesystem snapshots around mutation epochs #44511: the v2 snapshot redesign, which names this exact cause (changes from another session during a step being attributed to the assistant and overwritten by revert)
   • Undo in one session reverts all sessions #33940: the same symptom reported on v1
   • Session snapshot "restore/revert" bulk-overwrites the whole worktree with a stale baseline tree that is never rotated #49732, /undo destroyed 227 files, /restore destroyed 15,232 files. Several HUNDREDS OF THOUSANDS OF DOLLARS OF DAMAGE #53560, Snapshot restore from a subdirectory can overwrite sibling files #39513: other cases of snapshot restore overwriting files a session never touched

   Until this is fixed, the safest option is not to revert in one session while another session is editing the same worktree, or to give each session its own git worktree.

   Reproduction script (drive.ts)

   // Repro for #54026: reverting a message in session B rolls back edits that
   // another session (or any writer) made to the shared worktree while B's step ran.
   import { Effect } from "effect"
   import * as fs from "node:fs"
   import * as path from "node:path"
   import { Llm, OpenCodeDriver } from "opencode-drive"
   
   export default OpenCodeDriver.use(
     {
       ...(process.env.OC_DEV ? { opencode: { dev: process.env.OC_DEV } } : {}),
       project: {
         git: true,
         files: {
           "a.txt": "session A original\n",
           "untouched.txt": "never changed\n",
         },
       },
       // Drive disables snapshots by default; OpenCode enables them by default.
       config: { snapshots: true } as any,
       tools: ["shell"],
       tui: { recording: true },
     },
     ({ ui, llm, tools, opencode, artifacts }) =>
       Effect.gen(function* () {
         const dir = path.join(artifacts, "files")
         const shells = yield* tools.control("shell")
   
         // Session B: a step that only runs a read-only shell command.
         yield* llm.queue(
           Llm.toolCall({ index: 0, id: "call_ls", name: "shell", input: { command: "ls", description: "list" } }),
           Llm.finish("tool-calls"),
         )
         yield* llm.queue(Llm.text("Done listing files."))
         yield* ui.submit("list the files (sent by mistake)")
         const shell = yield* shells.take("call_ls")
   
         // Meanwhile "session A" edits a tracked file and creates a new one.
         fs.writeFileSync(path.join(dir, "a.txt"), "session A EDITED (uncommitted work)\n")
         fs.writeFileSync(path.join(dir, "a.test.ts"), "// new test written by session A\n")
         yield* Effect.log("before step end: a.txt=" + JSON.stringify(fs.readFileSync(path.join(dir, "a.txt"), "utf8")))
   
         yield* shell.succeed({ output: "a.txt\nuntouched.txt\n", exit: 0 })
         yield* ui.waitFor("Done listing files.")
         yield* Effect.sleep(1000)
   
         const sessions: any = yield* opencode.session.list()
         const session = (sessions.items ?? sessions.data ?? sessions)[0]
         const messages: any = yield* opencode.message.list({ sessionID: session.id } as any)
         const list: any[] = messages.items ?? messages.data ?? messages
         for (const m of list) yield* Effect.log(`msg ${m.id} ${m.type} snapshot=${JSON.stringify(m.snapshot)}`)
         const user = list.find((m) => m.type === "user")
   
         yield* Effect.log(`before revert: a.txt=${JSON.stringify(fs.readFileSync(path.join(dir, "a.txt"), "utf8"))} a.test.ts exists=${fs.existsSync(path.join(dir, "a.test.ts"))}`)
         // Same call the web UI makes: stage a revert of the mistaken message, no `files` flag.
         const revert = yield* opencode.session.revert.stage({ sessionID: session.id, messageID: user.id } as any)
         yield* Effect.log("revert staged: " + JSON.stringify(revert))
         yield* Effect.sleep(1500)
         const after = fs.readFileSync(path.join(dir, "a.txt"), "utf8")
         const exists = fs.existsSync(path.join(dir, "a.test.ts"))
         yield* Effect.log(`AFTER revert: a.txt=${JSON.stringify(after)} a.test.ts exists=${exists}`)
         yield* ui.screenshot("after-revert")
         yield* Effect.log(after.includes("EDITED") && exists ? "RESULT: other session's work preserved" : "RESULT: BUG - other session's work discarded")
       }),
   )

   Run it with opencode-drive: opencode-drive run ./drive.ts. It drives opencode from your PATH; set OC_DEV to the path of an OpenCode checkout to run that from source instead.
3. opencode-agent

   added

   reproduced

   severity:high

   on Oct 8, 2026