Failed to merge bases while cherry picking commit

Error message

Failed to merge bases while cherry picking commit {target}. Encountered a conflict while merging the commit's original bases/new bases.

What it means

Cherry-picking a commit requires merging its original merge bases (and 'onto' bases) into the new graph. This error is raised via format_base_merge_error when one of those base merges conflicted, meaning the commit could not be transplanted onto its new parent. The rebase aborts early with a formatted diagnostic describing which merge failed.

Solutions

Read the formatted error's base_merge_failed/onto_merge_failed detail to identify which commit failed.
Manually rebase or re-create the failing commit onto the target base, then retry the rebase.
Reduce the divergence: rebase the source branch onto the target first, or split the stack into smaller rebases.

Defensive patterns

Strategy: try-catch

Try / catch

match rebase_result {
    Err(e) if e.to_string().contains("Failed to merge bases while cherry picking") => {
        // parse formatted detail, re-create failing commit manually, then retry
    }
    other => other?,
}

Prevention

Keep stacks small and rebased frequently to limit divergence
Avoid external history rewrites (force-push/filter-repo) under rebased branches
Pre-fetch and integrate upstream before running moves/absorbs

When it happens

Trigger: Calling rebase where a Pick step's original base(s) or onto base(s) fail to merge (base_merge_failed or onto_merge_failed set in the CherryPickOutcome::MergeBaseFailed variant).

Common situations: Deeply diverged histories; commits whose parents were rewritten externally (e.g. force-push, filter-repo) so original bases no longer merge; move/absorb operations on heavily edited stacks.

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/641d39e53a89dfca. Report an issue: GitHub.

Appendix: source

Thrown at crates/but-rebase/src/graph_rebase/rebase.rs:98

                        | CherryPickOutcome::Identity(new_id) => {
                            let mut new_pick = pick.clone();
                            new_pick.id = new_id;
                            let new_idx = output_graph.add_node(Step::Pick(new_pick));
                            graph_mapping.insert(step_idx, new_idx);
                            if !pick.exclude_from_tracking {
                                history.update_mapping(pick.id, new_id);
                            }

                            new_idx
                        }
                        CherryPickOutcome::FailedToMergeBases {
                            base_merge_failed,
                            bases,
                            onto_merge_failed,
                            ontos,
                        } => {
                            // Exit early - the rebase failed because it encountered a commit it couldn't pick
                            bail!(format_base_merge_error(
                                pick.id,
                                base_merge_failed,
                                bases,
                                onto_merge_failed,
                                ontos
                            ));
                        }
                    }
                }
                Step::Reference { refname, mutable } => {
                    // Immutable references are kept in the graph for traversal
                    // but never moved, created, or deleted.
                    if mutable {
                        let graph_parents = collect_ordered_parents(&self.graph, step_idx);
                        let first_parent_idx = graph_parents
                            .first()
                            .context("References should have at least one parent")?;
                        let Some(new_idx) = graph_mapping.get(first_parent_idx) else {

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