ConfigKit/docs/roadmap/consolidation.md

ConfigKit Consolidation Toward 1.0

Status: proposed scope and target state for review. This document recommends refactors; it does not record implementation progress or authorize a release. Prepare the staged implementation plan after reviewing this roadmap.

Purpose

Consolidate the machinery introduced by recent import, collection, inheritance, and discovery work so ConfigKit is easier to understand, maintain, and adopt before its public contracts become stable. Success means fewer independently maintained paths through the same behavior, clearer state ownership, and concise consumer workflows. Reducing a function's line count is useful only when it serves those outcomes.

The review considered public API consolidation as well as internal extraction. The recommended scope retains the existing simple and layered loading APIs, consolidates their private translation and acquisition machinery, and removes unused reverse inspection conversions. No public signature or configuration semantic change is currently recommended. This is an assessment of the reviewed consumer workflows, not a requirement to preserve every beta API in perpetuity.

Evidence And Relationship To Existing Work

Reviewed worktree: c9574ef, immediately after the v0.10.0 release at 5959537. The inputs are the earlier complexity roadmap, whose reviewed baseline predates discovery, and the new complexity audit. The older roadmap already acknowledges implemented discovery, but its selected work is narrower than this proposal.

This review inspected the current public load/input/discovery declarations and maintained consumer examples, the shared request executor and acquisition flow, import parsing and selection, inheritance execution, reflective projection and cloning, schema field construction, and filesystem-context derivation. Graph caller traces and text-reference checks confirmed the unused reverse conversion chain. This was source review, not a new runtime correctness or performance audit. The audit's complexity scores locate candidates; they are not standardized acceptance thresholds or evidence of a runtime defect.

Audit finding	Assessment and recommended treatment
1. Import entry points and responsibilities	Main refactor. Include shared acquisition normalization, import-default ownership, declaration parsing, and directory admission.
2. Shared inheritance executor	Main refactor. Expose meaningful phases and explicit combination results while retaining one executor.
3. Projection and cloning	Main refactor for projection; bounded follow-up for substantial clone handlers, preserving the distinction between the operations.
4. Schema field discovery and inline assembly	Include a focused refactor coordinated with projection. Keep one schema builder and its two descriptor views.
5. Resolved filesystem context	Include alongside acquisition work. Reuse resolved facts without merging resource lifetimes or changing validation timing.
6. Unused reverse inspection conversions	Include as an independent cleanup in the root facade and engine. Retain useful forward-conversion and detached-result coverage.

This is the combined proposal for scope review, rather than a second independent implementation of the earlier roadmap. Keep the audit as evidence; its findings are not closed by adopting this document. Completed correctness and algorithmic remediations remain part of the baseline, including sequence records preserved at ea46001:docs/roadmap/remediation.md and discovery records preserved at 0369111:docs/roadmap/remediation.md.

The architecture policy, configuration contract, and exported declaration comments own existing constraints and behavior. The component overview and import internals locate implementation responsibilities.

Consumer-Facing Target

Keep Simple Loading Simple And Advanced Inputs Explicit

The current APIs already provide progressive setup:

• A simple consumer calls Load[Config](File(path)).
• A consumer with defaults, imports, or resolution supplies Options[Config].
• Explicit discovery produces an ordinary Source, so it uses the same loading call and lifecycle.
• A layered consumer supplies an Input and LayeredOptions[Config], with Underlay.Inputs distinguishing strict peers from precedence tiers.

The two loading functions already converge on loadRequest and executeLoadRequest. Their public differences have meaning: ordinary options include the one input's controls; layered loading has per-input controls and a separate overlay filesystem. Ordinary overlay context follows its selected source, whereas layered overlay context is independently specified. These are observable conventions, not interchangeable forwarding spellings.

Recommendation: retain Load, LoadLayered, Options, LayeredOptions, Input, and Underlay. Remove repeated translation and option reconstruction behind them. Keep common application rules in Definition; do not require applications to build a runtime loader or manually coordinate phases.

A single public request type could place main input, underlays, and common options together. It would reduce duplicated option fields and make promotion from ordinary to layered loading more uniform. However, a sole request-based entry would add setup to the simplest call; retaining a convenience entry would still leave two call forms. Either approach must explicitly resolve the existing overlay-context differences. The maintained examples do not yet show enough consumer benefit to justify that redesign. This recommendation is based on the resulting API, rather than the amount of refactoring needed to achieve it.

Preserve Useful Convenience And Ownership Boundaries

Surface reviewed	Recommended public end state
Source, Filesystem, Search, filename groups and presets	Retain typed, reusable source/search descriptions. Discovery selects a concrete source during loading; applications do not loop over complete loads.
FilesystemContext	Retain the public description and current host/native rules. Consolidate its resolved private representation; do not expose acquisition handles or engine context records.
SequenceIdentityAt and SequenceIdentityMatching	Retain the exact-path convenience and dynamic selector form over the common registration model. Both serve distinct consumer shapes.
Definition, resolution and validation callbacks	Retain application-owned domain rules inside one recorded lifecycle. Preserve the distinction between mutable recorded resolution and read-only validation.
Results, metadata, explanations, source context and diff	Retain detached, safe inspection with consumer-owned presentation. Remove unused inverse conversions without removing supported queries.
Root wrappers and private conversions	Retain root-owned public types and explicit ownership conversion under ADR 0006. Consolidate repeated real conversions and delete unused ones.

The consumer-facing work is to make the ordinary path easier to find and show how additional features compose, using the existing maintained examples. Update the adoption guide with a concise choice between simple loading, discovery, and layered loading, and show which options belong to an input versus a whole load. Keep exact behavior in its canonical owners. Examples should make application rules recognizable and avoid requiring consumers to recreate generic merging, presence, or provenance machinery.

Use the current simple README call, bundled-file and layered catalog examples, the import-focused prompt catalog, and the discovered sequence catalog to assess the end state. The latter exercises imports, underlays, independent overlay context, CLI assignment, and recorded resolution in one workflow. A high number of options in that example does not by itself justify a new abstraction.

Internal Target

Keep the root facade, cohesive internal/engine, ordered document model, and private YAML adapter. Use ordinary private records, functions, and focused files to express responsibilities. Existing mapping combination, sequence combination, dependency scheduling, schema descriptors, and traversal accounting remain shared.

executeLoadRequest stays the visible lifecycle coordinator. It should show acquisition, assembly, inheritance, decoding/CLI assignment, resolution, secret processing, validation, and publication in their established order. Extract a phase only when it gives that work a clear input, output, or ownership boundary. Do not replace the visible lifecycle with a registry of configurable stages.

1. Normalize Loading Inputs And Consolidate Import Acquisition

The current executor constructs an engine Options[T] from loadRequest, and underlay acquisition constructs Options[struct{}] to call the same input assembler. assembleBaseInputTrackedForRole then combines discovery, directive processing, version rules, imports, placement, accounting, and contexts. Import entry points carry long positional lists through several forwarding variants. This repeats the representation of information already normalized for a load.

Introduce cohesive private acquisition inputs and explicit state ownership, reusing loadRequest, loadInput, acquisitionScope, and importTraversal where they fit. Translate ordinary and layered public declarations into the shared loading model once. Acquisition should receive the source, input role, placement, context, and policies it needs without a fabricated application type or a reconstructed broad options object. Small adapters may preserve meaningful entry operations while callers migrate; remove obsolete forwarding variants within the completed refactor.

Separate immutable policy, mutable processing state, and results. Move import defaults out of sourceVersionState and into the load/acquisition policy owner. Version state continues to own version processing, projected effective version location, evidence, and diagnostics. Local and effective version rules have different meanings and must remain distinguishable.

The state boundaries are especially important:

Lifetime or scope	State and responsibility
Whole load	Aggregate resource accounting, application definition/registrations, import defaults, shared version evidence and diagnostics.
One strict tier	Repetition tracking shared by that tier's inputs, namespace scheduling anchors, and its inclusion/composition graph relationship. A later tier may reuse a file.
Active import traversal	Active routes and inclusion edges, filesystem access ownership, and cycle detection, including edges crossing item-scope boundaries.
One composition scope	Peer contributions, pending collection declarations, item-local helpers, and deferred item placement. Nested scopes do not become separate precedence tiers.
Retained result	Source records, effective destinations, origins, history, and passive resource-context descriptions.

The older roadmap's broad description of load-wide repetition state should not be implemented as a global visited-file restriction. In the current code, acquireUnderlayGroupScopes creates a fresh visited map per group. Preserve valid reuse across tiers while keeping shared aggregate limits. Namespace equality, candidate spelling, and stable scheduling keys also serve different purposes.

Give acquisition, already-acquired scope assembly, and evidence projection focused homes. Keep discovery at the acquisition boundary: resolve a search once per input consumption, then process the concrete file or absence. Preserve source IDs and source-local version processing in acquisition order, even when composition uses a different dependency-ready order. The layered main is acquired before underlays; lower-tier identity can still inform its later strict assembly.

Within import parsing, extract boolean/collection/placement field handling and selector-value parsing where it clarifies responsibilities. Keep field presence, authored error locations, selector applicability, and the order of consequential validation visible. Within directory selection, separate entry admission and descent decisions from traversal orchestration. Retain the existing root deduplication, candidate union, exclusions, sorting, and active-path cycle rules. No shared abstraction should conflate literal first-match main discovery with multi-file import selection.

2. Share Resolved Filesystem Facts Without Sharing Live Handles

importFilesystem, nativeFilesystemAccess, and contextsForAcquiredSources derive overlapping root/base/namespace facts. The latter reconstructs context from combinations of source kind and optional fields, including absent input. Discovery and independent layered overlays make these combinations consequential.

Use a small engine-owned resolved-context description for the facts actually needed by acquisition and passive views: namespace identity/kind, resolved root, source base, and selected source path when present. Preserve the distinction between host paths and native slash paths. Reuse already resolved facts where available instead of repeatedly deriving them from the original options.

Resolution and validation can occur at different existing lifecycle points. The record must not force every source to perform all filesystem checks early. Context descriptions, library-owned acquisition handles, and returned passive resource views have different lifetimes. Closing acquisition must remain explicit on success and failure; retaining context must not retain an open root handle or assume ownership of a borrowed fs.FS.

Cover selected and absent discovery outcomes, root-only absent host context, native sources, in-memory inputs with explicit context, and independently rooted overlays. Passive context remains associated with the source that contributed the value, including retained underlay and inherited values. Use the acquired source's canonical identity where available. Preserve containment failures, source associations, deferred search bases, and terminal selected-file errors.

Implement this work alongside acquisition consolidation so the same callers are not redesigned twice. The description is private; it does not replace the public FilesystemContext or ResourceContext contracts.

3. Make Inheritance Combination Results Explicit

Keep the mapping and identified-record adapters and one shared executor. applyInheritanceScopeTemplates currently prepares templates, mutates values through merge callbacks, projects policy and origins, records replacements and replay evidence, and enforces budgets in one body. The callbacks mutate several surrounding result collections, making a combination difficult to review alone.

Give the executor named operations for child/control preparation, parent payload and policy preparation, combination, evidence construction, and retained-node accounting. Use a small private result for outputs of one combination where it replaces unrelated surrounding mutations. Value, policy, origin, replacement, and sequence-position evidence should come from the same combination outcome; do not rerun a merge to reconstruct its history.

Keep borrowed authored templates separate from owned resolved payloads and from retained history snapshots. Parent identity exclusion and child identity/origin preservation must apply consistently to values and history. Preserve nested unresolved instructions for destination-local evaluation, policy retirement on actual replacement, cancellation, and source-version movement through sequences.

The shared Kahn scheduler with stable keys remains unchanged. Resolve enclosing relationships before nested relationships and retain assembled record order. Preserve expansion limits and retained-history accounting for shared nodes; extraction must not charge shared evidence twice or make an unbounded snapshot.

4. Separate Projection Handlers And Clarify Schema Assembly

Keep projectConfiguration as the schema-checked entry and valueOperation as the operation-state owner. Move substantial struct, map, and sequence projection into focused handlers. Keep pointer/dynamic dispatch and scalar representation choices visible. All handlers share the same cycle, depth, and node state.

Struct projection needs particular care: physical members drive traversal, flattened fields drive name lookup and sensitivity, and an inline container is not retained as an extra output node. Preserve declaration order, deterministic map order, nil/empty distinctions, collision diagnostics, codec failures, and secret classification. Keep cycle entries active through child traversal and balance their release on every exit.

In schemaBuilder.describeFields, separate field discovery and tag parsing from inline struct assembly, inline map assembly, and ordinary field registration. Retain one builder/cache and its recursion detection. Make the paired updates to members, flattened fields, fieldByName, and inlineMap easy to follow. Keep index-path construction and inherited secret flags intact. These descriptor views are both needed; combining them into one collection would shift complexity into decoding and projection.

Follow with a bounded cleanup of substantial clone handlers where it makes their ownership behavior easier to read. Keep cloning distinct from projection: cloning reconstructs typed values, preserves physical fields, round-trips text codecs, and distinguishes unresolved from already validated secret state. Projection builds a canonical document and charges output nodes. Extract common helpers only where the semantics actually agree. The mostly explicit dispatch in decodeValue and valueBuilder.build does not warrant a generic reflection visitor solely because it has a high complexity score.

5. Remove Unused Inspection Conversions And Consolidate Real Adapters

Remove toEngineSourceInfo, toEngineOrigin, the exclusive reverse version and import-selection converters, and the engine adapters used only by that chain. At the reviewed revision, the three callers of toEngineSourceInfo are tests; toEngineOrigin has none. SourceInfoWithPlacement, SourceInfoWithImportSelections, and their exclusive string-to-enum helpers have no production role beyond that reverse chain. Recheck callers at the implementation baseline before removal.

Rewrite the affected record tests around real engine-to-public conversion and detached public inspection. Preserve useful placement, version evidence, import-selection, and copy-isolation assertions. Avoid manufacturing replacement production setters solely to keep an old round-trip fixture working. Existing facade loads already provide genuine sources and inspection records.

Retain reverse conversions that serve real inputs: toEngineDiagnostics, for example, supports WriteDiagnostics. Consolidate repeated override/input conversion in toEngineOptions and toEngineLayeredOptions where semantics match. Keep explicit root-to-engine ownership conversion and the public-boundary checks. A reflective transport framework or public engine aliases would obscure the boundary rather than simplify it.

Scope, Compatibility, And Policy Consequences

The proposed work spans private engine code, private root-facade conversions, affected tests, consumer guidance, and implementation documentation. This is a deliberate expansion beyond the older engine-only roadmap. Preserve public types/signatures and the behavior owned by the current contracts, including:

• Acquisition versus composition ordering, strict scopes versus precedence tiers, identity ownership, placement, and source-version protection.
• Discovery exhaustion and error behavior, source lifetime, passive resource contexts, and host/native namespace distinctions.
• Defaults, post-decode CLI assignment, recorded resolution, secret handling, final registered-identity enforcement, and semantic validation.
• Explicit presence, provenance/history, sensitivity, safe diagnostics and diff, frozen inspection, and detached publication/query results.
• Contracted diagnostic codes, paths, coordinates, ordering, and resource limits.

Do not turn incidental helper order, exact private representations, numerical complexity scores, or allocation counts into new guarantees. Keep the existing algorithmic remediations effective; watch for repeated whole-tree traversals, policy scans, or copies introduced by helper extraction.

The recommendation fits the existing architecture policy and ADRs 0006, 0015, 0017, 0018, and 0019. It needs no new architectural ownership decision or policy revision merely to introduce private helpers. Update the component overview and import internals when code moves. Accepted ADR decision content remains unchanged. If review selects a materially different public loading model, assess its behavioral consequences explicitly before implementation.

Pre-1.0 public changes are possible under the release policy, but they must have a consumer benefit and documented impact. This draft does not propose a parallel compatibility API or temporary migration scaffold. It also does not make refactoring completion a new release gate or establish that 1.0 is otherwise ready. Future performance experiments remain in future.md; no benchmark campaign was run or is required to claim readability improvements.

Recommended Work Order

This is dependency guidance for the later plan, not a commit-by-commit schedule:

1. Confirm the reviewed revision and public-surface direction; map the retained behavior to existing tests and record concrete coverage gaps.
2. Remove unused reverse inspection conversions and adjust their tests. This is small and independently reviewable.
3. Normalize acquisition inputs and separate import-default ownership. Develop the resolved-context handoff with those callers, preserving validation and closure timing; then separate acquisition, item assembly, and evidence work.
4. Refactor inheritance around explicit preparation and combination results, retaining completed correctness and algorithmic regressions.
5. Refactor projection and schema field assembly in separate reviewable changes; complete the bounded clone cleanup where it improves the remaining flow.
6. Consolidate real facade adapters, finish consumer/internal navigation, and run the applicable integration and ownership checks on the combined result.

Steps 4 and 5 have no necessary implementation dependency on each other. Keep correctness fixes discovered during refactoring identifiable with their own regression evidence rather than hiding behavior changes inside code movement.

Validation And Completion

Use the development guide and testing policy for focused checks and the ordinary full development check. Preserve existing behavior tests; rewrite tests coupled only to removed plumbing. Add a test when a consequential handoff risk lacks coverage, not for every new helper.

Work area	Existing protection and review focus
Acquisition and imports	Selection, defaults, scheduling, relative/item placement, source-version evidence, aggregate limits, repetition within versus across tiers, and ordinary/layered equivalence.
Resolved contexts	Host/native access, discovery selected/absent outcomes, terminal context failures, source-relative resources, independent overlay context, and handle closure.
Inheritance	Mapping and record inheritance, nested destination-local evaluation, child identity, policy lifetime, version movement, history ordering, sensitivity, and retained-node budgets.
Projection/schema/clone	Inline fields, recursive schemas, dynamic values, nil/empty values, cycles and limits, text codecs, secret states, callback ownership, and independent loads.
Facade and consumers	Forward conversion, detached records, supported API boundaries, source-form equivalence, maintained simple/catalog/discovery examples, and safe explanation/diff.

Examples of established boundaries include source-form equivalence, discovery integration, final identity validation, inheritance history, and projection and cloning. Use applicable race checks when changing ownership or shared state. Reuse checks for unchanged content and keep benchmark work separate unless new evidence justifies it and it is authorized.

Completion requires reviewable evidence that:

• Simple and advanced consumer examples remain concise and valid, with no new public concepts required for existing workflows.
• Both load entry points reach one normalized internal model; acquisition no longer reconstructs broad options or uses version state to transport defaults.
• Import, context, inheritance, and reflection responsibilities have identifiable owners and explicit handoffs without duplicate semantic implementations.
• Unused reverse conversions and their exclusive adapters are removed, with useful inspection ownership coverage retained.
• Contracted values, presence, provenance/history, diagnostics, sensitivity, resource lifetime, and algorithmic corrections remain protected by appropriate tests and source review.
• The reviewed scope is accounted for against all six audit findings; completed findings have validation evidence rather than being closed because code moved.
• Consumer guidance, contributor references, and internal documentation describe the resulting implementation. Current contracts continue to own behavior.

Private type/helper names, final file splits, and exact stage boundaries belong in the implementation plan. The public-surface recommendation and scope above are ready for review; no additional feature semantics are needed to carry out the recommended refactors.