What causes "Could not reset submodule at '{sm_dir}' to commit {id}: {err}" in gitbutlerapp/gitbutler?

Inspect the {err} stderr in the message; run the same `git reset ` manually inside the submodule to see the full failure.

gitbutlerapp/gitbutler · error

Could not reset submodule at

Error message

Could not reset submodule at '{sm_dir}' to commit {id}: {err}

What it means

Wraps a failed attempt to reset a submodule working directory to the recorded commit via a shell git command (git reset) run inside the submodule's repository directory. The subprocess exited non-zero and the raw stderr is embedded in the message. It indicates the submodule could not be moved to the commit the outer discard operation requires.

Solutions

Inspect the {err} stderr in the message; run the same `git reset <commit>` manually inside the submodule to see the full failure.
Commit or stash local changes inside the submodule, then retry the discard.
Fetch the missing commit in the submodule (git fetch --unshallow or fetch origin) so the target commit exists.
Abort any in-progress merge/rebase in the submodule (git rebase --abort / git merge --abort) before resetting.

Defensive patterns

Strategy: try-catch

Validate before calling

// preflight: is the submodule clean and at resettable state?
let ok = Command::new("git").args(["status", "--porcelain"])
    .current_dir(submodule_repo_dir).output()?.status.success();

Try / catch

// parse stderr from the error chain to branch on cause
let msg = format!("{err:#}");
if msg.contains("local changes") { stash_and_retry()?; }
else if msg.contains("not found") { fetch_submodule_then_retry()?; }
else { return Err(err); }

Prevention

Keep submodules clean (commit or stash) before running discard operations
Initialize and fully fetch submodules so target commits exist locally
Avoid running discards while a submodule rebase/merge is in progress
Include the recorded submodule commit in CI checkouts (git submodule update --init)

When it happens

Trigger: restore_state_to_worktree encounters a submodule change whose target state commit differs from the submodule's current HEAD and runs `git reset` in the submodule dir; the command fails (dirty submodule, missing objects, merge/rebase in progress, corrupt repo).

Common situations: Submodules with local uncommitted changes or an in-progress rebase/merge; submodules cloned shallowly so the target commit is missing; read-only or CI sandboxes where git cannot write into the submodule; git hooks or config interfering.

Understand the failure class

Background: "git command failed": what it means when a tool shells out to git and git exits non-zero — this error's family across 21 libraries.

Related errors

AI-assisted analysis of gitbutlerapp/gitbutler@58e5313667 (2026-09-18). Data as JSON: /api/errors/df2cb82d30e8a5f4. Report an issue: GitHub.

Appendix: source

Thrown at crates/but-workspace/src/tree_manipulation/discard_worktree_changes.rs:311

                }
                update_index(gix::index::fs::Metadata::from_path_no_follow(&link_path)?)?;
            }
            EntryKind::Commit => {
                if let RestoreMode::Update = mode {
                    // TODO(gix): actual checkout/reset functionality - it will be fine to support that fully.
                    // Since `git2` doesn't support filters, it will save us some trouble to just use Git for that.
                    let submodule_repo_dir = &file_path;
                    let out = std::process::Command::from(
                        gix::command::prepare(format!(
                            "git reset --hard {id} && git clean -fxd",
                            id = state.id
                        ))
                        .with_shell(),
                    )
                    .current_dir(submodule_repo_dir)
                    .output()?;
                    if !out.status.success() {
                        bail!(
                            "Could not reset submodule at '{sm_dir}' to commit {id}: {err}",
                            sm_dir = submodule_repo_dir.display(),
                            id = state.id,
                            err = out.stderr.as_bstr()
                        );
                    }
                } else {
                    let sm_repo = repo
                        .submodules()?
                        .into_iter()
                        .flatten()
                        .find_map(|sm| {
                            let is_active = sm.is_active().ok()?;
                            is_active.then(|| -> anyhow::Result<_> {
                                Ok(
                                    if sm.path().ok().is_some_and(|sm_path| sm_path == rela_path) {
                                        sm.open()?
                                    } else {

View on GitHub (pinned to 58e5313667)