Remove the legacy non-graph commit engine

[krlvi]

No description provided.

[Copilot]

Pull request overview

This PR removes the legacy (non-graph) commit engine from but-workspace and migrates remaining call sites to the graph-rebase-based commit APIs, while deleting the legacy engine’s associated test suite.

Changes:

• Replace legacy commit-engine usage with but_rebase::graph_rebase::Editor + but_workspace::commit::{commit_create, commit_amend} in branch removal, CLI amend, rules processing, and simple automation flows.
• Remove the legacy commit engine module and large legacy commit-engine test coverage from but-workspace.
• Update crate dependencies to include but-rebase/tracing where needed.

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
crates/gitbutler-branch-actions/src/branch_manager/branch_removal.rs	Switch “WIP Assignments” commit creation during unapply from legacy engine to graph-rebase commit creation.
crates/but/src/command/legacy/rub/amend.rs	Migrate amend command to graph-rebase commit_amend and return the rewritten commit id.
crates/but-rules/src/handler.rs	Migrate rule-driven amend operations to graph-rebase commit_amend.
crates/but-rules/Cargo.toml	Add but-rebase and tracing dependencies for the new implementation.
crates/but-api/src/legacy/workspace.rs	Update stash_into_branch to use graph-rebase commit creation and adapt output shaping.
crates/but-action/src/simple.rs	Migrate simple “handle changes” commit creation flow to graph-rebase commit_create.
crates/but-workspace/src/legacy/mod.rs	Remove export of the legacy commit engine module.
crates/but-workspace/src/legacy/ui.rs	Remove StackEntryNoOpt::try_new helper previously used by the legacy engine.
crates/but-workspace/src/legacy/commit_engine/*	Delete legacy commit engine implementation files.
crates/but-workspace/tests/workspace/*	Remove legacy commit-engine test modules and associated helpers.
Cargo.lock	Lockfile updates for new dependency graph.

[Copilot]

Pull request overview

Copilot reviewed 20 out of 21 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 20 out of 21 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

crates/but-api/src/legacy/workspace.rs:413

• outcome is a Result from the commit/create+materialize block, but it isn’t ?-propagated before running reload_repo_and_invalidate_workspace, update_workspace_commit, and unapply. If the commit step fails, these follow-up mutations will still run and can both leave the repo/workspace in an unexpected state and/or mask the original error (because later ? calls can override it). Consider applying ? at assignment (let outcome = { ... }?;) or immediately after, then proceed with the subsequent workspace updates only on success.

    ctx.reload_repo_and_invalidate_workspace(perm)?;

    gitbutler_branch_actions::update_workspace_commit(ctx, false)
        .context("failed to update gitbutler workspace")?;

    ctx.branch_manager().unapply(
        stack.id,
        perm,
        false,
        Vec::new(),
        ctx.settings.feature_flags.cv3,
    )?;