What causes "commits cannot be moved to the merge base" in gitbutlerapp/gitbutler?

Choose a concrete commit or branch tip as the move target.

commits cannot be moved to the merge base

Error message

commits cannot be moved to the merge base

What it means

In the status TUI's move mode (crates/but/src/command/legacy/status/tui/app/move_mode.rs:393), the selected target is converted to a move::MoveTarget; the merge-base lane (MoveTarget::MergeBase) is deliberately rejected because commits can only be moved onto a branch tip, a commit (with an insert side), or a linked-worktree tip — never onto the merge base itself.

Source

Thrown at crates/but/src/command/legacy/status/tui/app/move_mode.rs:393

        Ok(())
    }
}

fn move_target(
    target: MoveTarget<'_>,
    insert_side: InsertSide,
) -> anyhow::Result<r#move::MoveTarget> {
    Ok(match target {
        MoveTarget::Branch { name } => r#move::MoveTarget::BranchTip {
            name: Category::LocalBranch.to_full_name(name)?,
        },
        MoveTarget::Commit(commit) => r#move::MoveTarget::Commit {
            commit,
            side: targeting::Side::from(insert_side),
        },
        MoveTarget::WorktreeTip(name) => r#move::MoveTarget::BranchTip { name },
        MoveTarget::MergeBase => anyhow::bail!("commits cannot be moved to the merge base"),
    })
}

fn move_with(
    ctx: &mut Context,
    move_op: MoveOperation,
) -> anyhow::Result<Option<SelectAfterReload>> {
    let mut guard = ctx.exclusive_worktree_access();
    let mut meta = ctx.meta()?;
    let (outcome, _ws) = r#move::run(ctx, &mut meta, guard.write_permission(), move_op)?;

    Ok(match outcome {
        MoveOperationOutcome::Commits { moved_commits, .. } => {
            Some(SelectAfterReload::Commit(moved_commits.head.commit_id))
        }
        MoveOperationOutcome::Changes { new_commit, .. } => {
            Some(SelectAfterReload::Commit(new_commit.commit_id))
        }

View on GitHub (pinned to caf1f223d3)

Solutions

Choose a concrete commit or branch tip as the move target.
To move a commit to the bottom of a stack, target the first commit of that stack instead.
Fix the selection UI so the merge-base lane is non-selectable in move mode, preventing the error entirely.

Example fix

// before
let target = MoveTarget::MergeBase; // then converted -> bails

// after
let target = MoveTarget::Commit(first_commit_of_stack);

Defensive patterns

Strategy: validation

Validate before calling

if matches!(target, MoveTarget::MergeBase) {
    // exclude merge-base lanes from selectable move targets in the UI
    return Ok(());
}

Type guard

fn is_valid_move_target(target: &MoveTarget<'_>) -> bool {
    !matches!(target, MoveTarget::MergeBase)
}

Try / catch

if let Err(err) = move_with(&mut ctx, move_op) {
    if err.to_string().contains("merge base") {
        // re-enter move mode and prompt for a commit/branch-tip target
    } else { return Err(err); }
}

Prevention

Filter merge-base rows out of move-target selection in the TUI.
Route 'move to bottom of stack' intents to the first commit of the stack.
Unit-test the MoveTarget conversion for every variant.

When it happens

Trigger: Entering move mode and accepting the merge-base/merge-commit row as the destination; a keybinding or selection handler that allows the merge-base heading to be picked as a move target.

Common situations: Users trying to move a commit to the very bottom of a stack; new key handlers or fuzzy selectors that do not filter out the merge-base lane.

Related errors

AI-assisted analysis of gitbutlerapp/gitbutler@caf1f223d3 (2026-08-20). Data as JSON: /api/errors/c18c3524425295ca. Report an issue: GitHub.