Make runAiMerge (the FN-5633 clean-room AI merge path, already the default)
the sole merge path; soft-deprecate the legacy aiMergeTask pipeline. Phase 0
of the workspace-mode master plan — a standalone merge-consolidation refactor
that lands first so downstream workspace work targets one merge function.
U1 — collapse the dispatch: project-engine.ts now calls runAiMerge
unconditionally; the two direct callers that bypassed the dispatch
(dashboard.ts onMergeImpl in --no-engine mode, task.ts runTaskMerge /
`fn task merge`) now route to runAiMerge too. Export runAiMerge from
@fusion/engine.
U2 — soft-deprecate: aiMergeTask is @deprecated (body retained for a later
deletion pass; shared helpers runAiMerge imports, e.g.
captureSingleCommitLandedMetadata, left intact). merger.mode "deterministic"
is annotated deprecated and made inert (type + field kept — published
@runfusion/fusion surface); the dispatch logs a one-time deprecation warning
and routes to runAiMerge. Changeset added (minor).
U3 — R7 workspace merge-boundary guard: shared @fusion/core predicate
assertNotWorkspaceTaskMerge(task) rejects tasks with populated
workspaceWorktrees at all four merge entry points (dispatch, store.mergeTask,
onMergeImpl, runTaskMerge) with an error naming master-plan U6. Covers the
window until per-repo merge support lands; U6 removes it.
U4 — deterministic-mode blast-radius audit: no production project, CI config,
or seeded setting pins merger.mode "deterministic"; only four engine tests
used it to drive the dispatch to aiMergeTask as a mockable seam — migrated to
mock runAiMerge instead. Other module-level aiMergeTask mocks were dead under
the default "ai" mode or test aiMergeTask directly (body retained), so they
are unaffected.
Also removes an unused acquireWorkspaceRepoWorktree import inherited from the
foundation branch (executor.ts) that was failing lint; master-plan U1 re-adds
it with its per-repo usage.
Merge gate green: lint, typecheck (29 projects), build, test:gate
(649 + 58), plus the migrated (114) and new predicate (4) tests.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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