WORK-359
ID:WORK-359Status:done

Per-instance variant resolution and merge over base config

Resolve each variant axis per instance and merge matching deltas over the base config before layout assembly, reusing the existing mergeThemeConfig machinery.

Priority:highComplexity:complexMilestone:v0.20.0Source:SPEC-091
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Criteria completion

Criteria completion: 3 of 3 (100%) checked; tracking started on Jun 9, no incremental history yet0%25%50%75%100%Jun 9Jun 15

Tracking started Jun 9 — check back for trends.

Relationships

Implements 1
Branches 3
main current done
claude/mcp-server-verify-4lnxej readyclaude/spec-091-engine-variants donemain done

Acceptance Criteria

  • Per instance the engine resolves modifier values (with default fallback) and merges variants[axis][value] over base before assembly; no separate condition language and no defaultVariants.
  • Merge reuses mergeThemeConfig by-key semantics (delta layout.root replaces; new wrapper keys add) in variants declaration order; the layout assembler is unchanged.
  • Themes can add/override a rune's variants via mergeThemeConfig.

Approach

Resolution is per-instance and happens before layout assembly; the static layout primitive is untouched. mergeThemeConfig in packages/transform/src/merge.ts. SPEC-091 §2–§3, §6.

References

  • SPEC-091

Resolution

Completed: 2026-06-09

Branch: claude/spec-091-engine-variants

What was done

  • packages/transform/src/engine.ts: resolveVariantConfig resolves each axis's modifier value (with default) and merges matching deltas over base — in declaration order — before layout assembly.
  • packages/transform/src/merge.ts: exported mergeRuneConfig (reused by the engine) and made it merge variants by axis→value so themes can extend them.

Notes

  • No separate condition language, no defaultVariants; the layout assembler is unchanged.