Wire load lifecycle through input acquisition

2026-10-25 13:07:16 +00:00
parent bd51b9c3f2
commit 0d149e51f0
9 changed files with 140 additions and 117 deletions
--- a/docs/roadmap/implementation.md
+++ b/docs/roadmap/implementation.md
@@ -1,6 +1,6 @@
 # Consolidation Implementation Plan

-Status: in progress. Stages 1 through 5 are complete; follow Stage 6 through Stage 20 in order.
+Status: in progress. Stages 1 through 6 are complete; follow Stage 7 through Stage 20 in order.
 The target executor is a Luna coding agent working through one end-to-end sprint.

 ## Authority, Baseline, And Execution
@@ -308,7 +308,7 @@ yet because the remaining ordinary and grouped assembly callers are scheduled
 for Stage 6; verification is deferred until that integration. `git diff --check`
 passed.

-## Stage 6 — Wire Ordinary And Grouped Lifecycle To Acquisition
+## Stage 6 — Wire Ordinary And Grouped Lifecycle To Acquisition (Complete)

 **Owners:** engine `load.go`, `load_request.go`, `load_input.go`, related tests.

@@ -339,6 +339,14 @@ passed.
 for acquisition. The shared path is wired end to end; context and import-flow
 extraction continue in later stages.

+Progress notes (2026-10-25): `executeLoadRequest` now creates one acquisition
+policy/state and acquires the main input through `acquireInput`; underlay groups
+reuse those load owners with a fresh tier state. Removed the generic base-input
+assembly variants and the acquisition-only fields from `Options`, and adapted
+direct tests to construct named requests. A search-source regression was caught
+and fixed during verification. The focused engine selection, facade selection,
+consumer example tests, and `GOTOOLCHAIN=local GOPROXY=off go test ./...` passed.
+
 ## Stage 7 — Separate Resolved Filesystem Facts From Access

 **Owners:** new engine `filesystem_context.go`, `filesystem.go`,
--- a/internal/engine/acquisition.go
+++ b/internal/engine/acquisition.go
@@ -169,6 +169,7 @@ func acquireInput(request inputAcquisitionRequest, policy acquisitionPolicy, sta
 			versionState.mainProcessing = &processed
 		}
 	}
+	request.input.source = selectedSource
 	if request.input.imports && selectedSource.kind != sourceNone {
 		importRequest := importAcquisitionRequest{input: request, main: parsed, processing: versionProcessing}
 		input.composition, input.sources, diagnostics = acquireImportedInput(importRequest, &policy, state, tier)
@@ -233,3 +234,21 @@ func acquireInput(request inputAcquisitionRequest, policy acquisitionPolicy, sta
 	}
 	return input, nil
 }
+
+func registerAcquiredSource(source Source, context *FilesystemContext, info *SourceInfo, visited map[resourceIdentity]importRoute, hostToken *namespaceToken) *Diagnostic {
+	if visited == nil || info == nil || info.Path == "" {
+		return nil
+	}
+	identity := resourceIdentity{namespace: hostToken, path: info.Path}
+	if source.kind == sourceFilesystem {
+		identity.namespace = source.namespace.token
+	} else if context != nil && context.FS != nil {
+		identity.namespace = context.FS.namespace.token
+	}
+	if previous, repeated := visited[identity]; repeated {
+		value := importRepeatedDiagnostic(Location{SourceID: info.ID}, previous, importRoute{})
+		return &value
+	}
+	visited[identity] = importRoute{canonical: info.Path}
+	return nil
+}
--- a/internal/engine/destination_accounting_test.go
+++ b/internal/engine/destination_accounting_test.go
@@ -409,7 +409,7 @@ func TestSelectedOverlayAndCLIUsePlacementNodeCharges(t *testing.T) {
 			overlay:   "test", overlayFilesystem: &FilesystemContext{Root: ".", BaseDir: ".", FS: &filesystem},
 		}
 		accounting := &importAccounting{nodes: limits.nodes - baseNodes}
-		_, diagnostics := assembleLayeredInput(request, assembledInput{}, accounting)
+		_, diagnostics := testAssembleLayeredInput(request, assembledInput{}, accounting)
 		if len(diagnostics) != 1 || diagnostics[0].Code != CodeOverlayLimitExceeded {
 			t.Fatalf("overlay diagnostics = %#v", diagnostics)
 		}
@@ -428,7 +428,7 @@ func TestSelectedOverlayAndCLIUsePlacementNodeCharges(t *testing.T) {
 			overrides: []Override{override},
 		}
 		accounting := &importAccounting{nodes: limits.nodes - baseNodes - overrideNodes + 1}
-		input, diagnostics := assembleLayeredInput(request, assembledInput{}, accounting)
+		input, diagnostics := testAssembleLayeredInput(request, assembledInput{}, accounting)
 		if len(diagnostics) != 0 {
 			t.Fatalf("assembly diagnostics = %#v", diagnostics)
 		}
@@ -440,3 +440,15 @@ func TestSelectedOverlayAndCLIUsePlacementNodeCharges(t *testing.T) {
 		}
 	})
 }
+
+func testAssembleLayeredInput[T any](request loadRequest[T], input assembledInput, accounting *importAccounting) (assembledInput, []Diagnostic) {
+	if accounting == nil {
+		accounting = &importAccounting{}
+	}
+	policy := acquisitionPolicy{
+		importDefaults: snapshotImportDefaults(request.importDefaults),
+		sequencePolicy: request.sequencePolicy,
+		importLimits:   defaultImportLimits(),
+	}
+	return assembleLayeredInput(request, input, policy, &acquisitionState{accounting: accounting, versionState: input.versionState})
+}
--- a/internal/engine/destination_import_test.go
+++ b/internal/engine/destination_import_test.go
@@ -163,11 +163,10 @@ func TestEntryDestinationSurvivesImportSetupAndParseFailures(t *testing.T) {
 	t.Run("import context failure", func(t *testing.T) {
 		directory := t.TempDir()
 		mainPath := writeImportFile(t, directory, "main.yml", "configkit: {imports: [{path: child.yml}]}\n")
-		input, diagnostics := assembleBaseInputTracked(
-			File(mainPath),
-			Options[map[string]any]{Imports: true, Filesystem: &FilesystemContext{Root: t.TempDir()}},
-			Keys("mounted"), &importAccounting{}, nil, nil,
-		)
+		input, diagnostics := testAcquireInput(inputAcquisitionRequest{
+			input: loadInput{source: File(mainPath), imports: true, filesystem: &FilesystemContext{Root: t.TempDir()}, destination: Keys("mounted")},
+			role:  sourceVersionMain, directiveContext: rootDirectiveContextImportsOnly,
+		}, acquisitionPolicy{importLimits: defaultImportLimits()}, nil)
 		if len(diagnostics) != 1 || diagnostics[0].Code != CodeImportOutsideRoot {
 			t.Fatalf("context diagnostics = %#v", diagnostics)
 		}
@@ -180,10 +179,10 @@ func TestEntryDestinationSurvivesImportSetupAndParseFailures(t *testing.T) {
 		directory := t.TempDir()
 		mainPath := writeImportFile(t, directory, "main.yml", "configkit: {imports: [{path: broken.yml}]}\n")
 		writeImportFile(t, directory, "broken.yml", "broken: [\n")
-		input, diagnostics := assembleBaseInputTracked(
-			File(mainPath), Options[map[string]any]{Imports: true},
-			Keys("mounted"), &importAccounting{}, nil, nil,
-		)
+		input, diagnostics := testAcquireInput(inputAcquisitionRequest{
+			input: loadInput{source: File(mainPath), imports: true, destination: Keys("mounted")},
+			role:  sourceVersionMain, directiveContext: rootDirectiveContextImportsOnly,
+		}, acquisitionPolicy{importLimits: defaultImportLimits()}, nil)
 		if len(diagnostics) != 1 || diagnostics[0].Code != CodeYAMLInvalid {
 			t.Fatalf("parse diagnostics = %#v", diagnostics)
 		}
--- a/internal/engine/imports_test.go
+++ b/internal/engine/imports_test.go
@@ -113,10 +113,13 @@ tasks: [{id: z-parent}]
 	aIndependentPath := writeImportFile(t, directory, "a-independent.yml", "tasks: [{id: a-independent}]\n")
 	bDependencyPath := writeImportFile(t, directory, "b-dependency.yml", "tasks: [{id: b-dependency}]\n")

-	input, diagnostics := assembleBaseInput[config](File(mainPath), Options[config]{
-		Imports:        true,
+	input, diagnostics := testAcquireInput(inputAcquisitionRequest{
+		input: loadInput{source: File(mainPath), imports: true}, role: sourceVersionMain,
+		directiveContext: rootDirectiveContextImportsOnly,
+	}, acquisitionPolicy{
 		sequencePolicy: mustCompileSequenceIdentityPolicy(t, []sequenceIdentityRegistration{{selector: sequenceIdentitySelector{literalSequenceSelector("tasks")}, identityFields: []string{"id"}}}),
-	})
+		importLimits:   defaultImportLimits(),
+	}, nil)
 	if len(diagnostics) != 0 {
 		t.Fatalf("assemble imports: %#v", diagnostics)
 	}
@@ -617,9 +620,10 @@ id: item
 `)
 	helperPath := writeImportFile(t, directory, "helper.yml", "value: acquired\n")
 	accounting := &importAccounting{}
-	input, diagnostics := assembleBaseInputTracked(File(mainPath), Options[struct{}]{
-		Imports: true, Filesystem: &FilesystemContext{Root: directory}, deferAssembly: true,
-	}, Path{}, accounting, nil, nil)
+	input, diagnostics := testAcquireInput(inputAcquisitionRequest{
+		input: loadInput{source: File(mainPath), imports: true, filesystem: &FilesystemContext{Root: directory}},
+		role:  sourceVersionMain, directiveContext: rootDirectiveContextImportsOnly, deferAssembly: true,
+	}, acquisitionPolicy{importLimits: defaultImportLimits()}, accounting)
 	if len(diagnostics) != 0 {
 		t.Fatalf("acquire input: %#v", diagnostics)
 	}
@@ -674,7 +678,10 @@ func TestItemImportCanJoinAnAuthoredListUnderRegisteredComposition(t *testing.T)
 `)
 	writeImportFile(t, directory, "item.yml", "configkit: {imports: [{path: helper.yml}]}\nname: imported\n")
 	writeImportFile(t, directory, "helper.yml", "id: helper-id\n")
-	input, diagnostics := assembleBaseInput(File(mainPath), Options[config]{Imports: true})
+	input, diagnostics := testAcquireInput(inputAcquisitionRequest{
+		input: loadInput{source: File(mainPath), imports: true}, role: sourceVersionMain,
+		directiveContext: rootDirectiveContextImportsOnly,
+	}, acquisitionPolicy{importLimits: defaultImportLimits()}, nil)
 	if len(diagnostics) != 0 {
 		t.Fatalf("assemble item import: %#v", diagnostics)
 	}
@@ -951,7 +958,10 @@ func TestItemAcquisitionRetainsInclusionGraphAndScopeOwnership(t *testing.T) {
 	itemPath := writeImportFile(t, directory, "item.yml", "configkit: {imports: [{path: helper.yml}]}\nname: item\n")
 	helperPath := writeImportFile(t, directory, "helper.yml", "id: supplied\n")

-	input, diagnostics := assembleBaseInput[importTestConfig](File(mainPath), Options[importTestConfig]{Imports: true})
+	input, diagnostics := testAcquireInput(inputAcquisitionRequest{
+		input: loadInput{source: File(mainPath), imports: true}, role: sourceVersionMain,
+		directiveContext: rootDirectiveContextImportsOnly,
+	}, acquisitionPolicy{importLimits: defaultImportLimits()}, nil)
 	if len(diagnostics) != 0 {
 		t.Fatalf("assemble input: %#v", diagnostics)
 	}
@@ -1104,7 +1114,10 @@ func TestItemHelperScopeScheduleInterleavesUnequalBranches(t *testing.T) {
 	writeImportFile(t, directory, "b-parent.yml", "configkit: {imports: [{path: a-dependency.yml}]}\nb: true\n")
 	writeImportFile(t, directory, "a-dependency.yml", "a: true\n")
 	writeImportFile(t, directory, "c-independent.yml", "c: true\n")
-	input, diagnostics := assembleBaseInput[importTestConfig](File(mainPath), Options[importTestConfig]{Imports: true})
+	input, diagnostics := testAcquireInput(inputAcquisitionRequest{
+		input: loadInput{source: File(mainPath), imports: true}, role: sourceVersionMain,
+		directiveContext: rootDirectiveContextImportsOnly,
+	}, acquisitionPolicy{importLimits: defaultImportLimits()}, nil)
 	if len(diagnostics) != 0 {
 		t.Fatalf("assemble item scope: %#v", diagnostics)
 	}
@@ -1420,6 +1433,15 @@ func testImportRequest(source Source, context *FilesystemContext, main parsedSou
 	}
 }

+func testAcquireInput(request inputAcquisitionRequest, policy acquisitionPolicy, accounting *importAccounting) (assembledInput, []Diagnostic) {
+	if accounting == nil {
+		accounting = &importAccounting{}
+	}
+	state := &acquisitionState{accounting: accounting}
+	tier := &tierAcquisitionState{visited: make(map[resourceIdentity]importRoute)}
+	return acquireInput(request, policy, state, tier)
+}
+
 func testAcquireImport(request importAcquisitionRequest, policy acquisitionPolicy, state *acquisitionState, tier *tierAcquisitionState) (*composedDocument, []SourceInfo, []Diagnostic) {
 	return acquireImportedInput(request, &policy, state, tier)
 }
--- a/internal/engine/load.go
+++ b/internal/engine/load.go
@@ -35,9 +35,6 @@ type Options[T any] struct {
 	importDefaults    importDefaults
 	destination       Path
 	placementMode     placementMode
-	sequencePolicy    sequencePolicy
-	deferAssembly     bool
-	directiveContext  rootDirectiveContext
 }

 // FilesystemContext supplies filesystem roots for imports and overlays. For an
@@ -184,17 +181,10 @@ func loadWithSecretLookup[T any](source Source, secrets SecretBinding, lookup se
 func executeLoadRequest[T any](request loadRequest[T], secrets SecretBinding, lookup secretLookup) (*Loaded[T], error) {
 	accumulator := diagnosticAccumulator{}
 	accounting := &importAccounting{}
-	mainOptions := Options[T]{Definition: request.definition, Imports: request.main.imports, Filesystem: request.main.filesystem, destination: request.main.destination.clone(), placementMode: request.main.placementMode}
-	mainOptions.importDefaults = snapshotImportDefaults(request.importDefaults)
-	mainOptions.sequencePolicy = request.sequencePolicy
-	mainOptions.deferAssembly = true
-	mainOptions.SourceVersionMode = request.sourceVersionMode
-	mainOptions.Definition.Version = request.protectionVersion()
-	if request.ordinary {
-		mainOptions.Overlay = request.overlay
-		mainOptions.directiveContext = rootDirectiveContextSource
-	} else {
-		mainOptions.directiveContext = rootDirectiveContextLayered
+	policy := acquisitionPolicy{
+		importDefaults: snapshotImportDefaults(request.importDefaults),
+		sequencePolicy: request.sequencePolicy,
+		importLimits:   defaultImportLimits(),
 	}

 	var schema *schemaDescriptor
@@ -209,8 +199,19 @@ func executeLoadRequest[T any](request loadRequest[T], secrets SecretBinding, lo
 	versionState := &sourceVersionState{
 		localRule: request.definition.Version, effectiveRule: request.protectionVersion(), mode: request.sourceVersionMode,
 	}
+	state := &acquisitionState{accounting: accounting, versionState: versionState}
 	accumulator.versionState = versionState
-	input, diagnostics := assembleBaseInputTrackedWithVersion(request.main.source, mainOptions, request.main.destination, accounting, nil, nil, versionState)
+	directiveContext := rootDirectiveContextLayered
+	ordinaryOverlay := ""
+	if request.ordinary {
+		directiveContext = rootDirectiveContextSource
+		ordinaryOverlay = request.overlay
+	}
+	input, diagnostics := acquireInput(inputAcquisitionRequest{
+		input: request.main, role: sourceVersionMain, directiveContext: directiveContext,
+		protectionRule: request.protectionVersion(), deferAssembly: true,
+		ordinaryOverlay: ordinaryOverlay,
+	}, policy, state, &tierAcquisitionState{visited: make(map[resourceIdentity]importRoute)})
 	request.main.source = input.source
 	accumulator.sources = input.sources
 	accumulator.add(versionState.diagnostics...)
@@ -228,7 +229,7 @@ func executeLoadRequest[T any](request loadRequest[T], secrets SecretBinding, lo
 		}
 	}
 	if request.ordinary && (input.document != nil || input.composition != nil) {
-		input.composition, diagnostics = compositionForInputWithPolicy(input, request.sequencePolicy)
+		input.composition, diagnostics = compositionForInputWithPolicy(input, policy.sequencePolicy)
 		if len(diagnostics) != 0 {
 			accumulator.add(diagnostics...)
 			return nil, accumulator.loadError()
@@ -244,10 +245,9 @@ func executeLoadRequest[T any](request loadRequest[T], secrets SecretBinding, lo
 	}
 	if request.ordinary {
 		versionState.locateMainVersion(input.document)
-		mainOptions.Definition.Version = versionState.effectiveRule
-		input, diagnostics = applyInputLayers(request.main.source, mainOptions, input)
+		input, diagnostics = applyInputLayers(request.main.source, request.main.filesystem, request.overlay, versionState.effectiveRule, policy.sequencePolicy, input)
 	} else {
-		input, diagnostics = assembleLayeredInput(request, input, accounting)
+		input, diagnostics = assembleLayeredInput(request, input, policy, state)
 	}
 	accumulator.add(versionState.diagnostics[reportedVersionDiagnostics:]...)
 	accumulator.sources = input.sources
@@ -279,7 +279,7 @@ func executeLoadRequest[T any](request loadRequest[T], secrets SecretBinding, lo
 			return nil, accumulator.loadError()
 		}
 		expanded, problems := expandInheritanceWithCollectionRules(
-			composition.root, composition.origins, composition.collectionPolicies, request.sequencePolicy, defaultProjectionLimits(),
+			composition.root, composition.origins, composition.collectionPolicies, policy.sequencePolicy, defaultProjectionLimits(),
 		)
 		if len(problems) != 0 {
 			accumulator.add(problems...)
@@ -351,7 +351,7 @@ func executeLoadRequest[T any](request loadRequest[T], secrets SecretBinding, lo
 	if hasErrors(secretResolution.diagnostics) {
 		return nil, accumulator.loadError()
 	}
-	identityDiagnostics := validateFinalSequenceIdentities(resolved.referenceInput, request.sequencePolicy)
+	identityDiagnostics := validateFinalSequenceIdentities(resolved.referenceInput, policy.sequencePolicy)
 	accumulator.add(identityDiagnostics...)
 	if hasErrors(identityDiagnostics) {
 		return nil, accumulator.loadError()
--- a/internal/engine/load_input.go
+++ b/internal/engine/load_input.go
@@ -88,59 +88,27 @@ func cloneAcquisitionScopes(scopes []acquisitionScope) []acquisitionScope {
 	return cloned
 }

-func assembleBaseInput[T any](source Source, options Options[T]) (assembledInput, []Diagnostic) {
-	return assembleBaseInputTracked(source, options, Path{}, &importAccounting{}, nil, nil)
-}
-
-func assembleBaseInputTracked[T any](source Source, options Options[T], destination Path, accounting *importAccounting, visited map[resourceIdentity]importRoute, hostToken *namespaceToken) (assembledInput, []Diagnostic) {
-	return assembleBaseInputTrackedWithVersion(source, options, destination, accounting, visited, hostToken, nil)
-}
-
-func assembleBaseInputTrackedWithVersion[T any](source Source, options Options[T], destination Path, accounting *importAccounting, visited map[resourceIdentity]importRoute, hostToken *namespaceToken, versionState *sourceVersionState) (assembledInput, []Diagnostic) {
-	return assembleBaseInputTrackedForRole(source, options, destination, accounting, visited, hostToken, versionState, sourceVersionMain)
-}
-
-func registerAcquiredSource(source Source, context *FilesystemContext, info *SourceInfo, visited map[resourceIdentity]importRoute, hostToken *namespaceToken) *Diagnostic {
-	if visited == nil || info == nil || info.Path == "" {
-		return nil
-	}
-	identity := resourceIdentity{namespace: hostToken, path: info.Path}
-	if source.kind == sourceFilesystem {
-		identity.namespace = source.namespace.token
-	} else if context != nil && context.FS != nil {
-		identity.namespace = context.FS.namespace.token
-	}
-	if previous, repeated := visited[identity]; repeated {
-		value := importRepeatedDiagnostic(Location{SourceID: info.ID}, previous, importRoute{})
-		return &value
-	}
-	visited[identity] = importRoute{canonical: info.Path}
-	return nil
-}
-
-func applyInputLayers[T any](source Source, options Options[T], input assembledInput) (assembledInput, []Diagnostic) {
-	if !activeOverlay(options.Overlay) {
+func applyInputLayers(source Source, filesystem *FilesystemContext, overlay string, protectionRule *VersionRule, policy sequencePolicy, input assembledInput) (assembledInput, []Diagnostic) {
+	if !activeOverlay(overlay) {
 		return input, nil
 	}
-	composition, diagnostics := compositionForInputWithPolicy(input, options.sequencePolicy)
+	composition, diagnostics := compositionForInputWithPolicy(input, policy)
 	if len(diagnostics) != 0 {
 		return input, diagnostics
 	}
 	assembly := newAssemblyAccumulator(composition)
-	if activeOverlay(options.Overlay) {
-		input.sources, diagnostics = loadSelectedOverlayIntoWithVersion(
-			source, options.Filesystem, input.parsed, assembly, input.sources,
-			options.Overlay, options.Definition.Version, defaultImportLimits(), input.versionState, options.sequencePolicy,
-		)
-		if len(diagnostics) != 0 {
-			return input, diagnostics
-		}
-		contexts, diagnostic := contextsForAcquiredSources(source, options.Filesystem, input.parsed.source, input.sources[len(input.sources)-1:])
-		if diagnostic != nil {
-			return input, []Diagnostic{*diagnostic}
-		}
-		mergeResourceContexts(&input.contexts, contexts)
+	input.sources, diagnostics = loadSelectedOverlayIntoWithVersion(
+		source, filesystem, input.parsed, assembly, input.sources,
+		overlay, protectionRule, defaultImportLimits(), input.versionState, policy,
+	)
+	if len(diagnostics) != 0 {
+		return input, diagnostics
 	}
+	contexts, diagnostic := contextsForAcquiredSources(source, filesystem, input.parsed.source, input.sources[len(input.sources)-1:])
+	if diagnostic != nil {
+		return input, []Diagnostic{*diagnostic}
+	}
+	mergeResourceContexts(&input.contexts, contexts)
 	input.composition = assembly.current
 	input.document = assembly.current.root
 	return input, nil
--- a/internal/engine/load_request.go
+++ b/internal/engine/load_request.go
@@ -79,16 +79,14 @@ func loadGroupedWithSecretLookup[T any](request loadRequest[T], secrets SecretBi
 	return executeLoadRequest(request, secrets, lookup)
 }

-func assembleLayeredInput[T any](request loadRequest[T], input assembledInput, accounting *importAccounting) (assembledInput, []Diagnostic) {
+func assembleLayeredInput[T any](request loadRequest[T], input assembledInput, policy acquisitionPolicy, state *acquisitionState) (assembledInput, []Diagnostic) {
 	var assembly *assemblyAccumulator
 	mainSourceCount := len(input.sources)
 	mainEvidence := input.versionState.evidenceSince(0)
 	projectVersion := sequenceVersionPath(request.protectionVersion())
 	for index, group := range request.underlays {
 		evidenceStart := len(input.versionState.evidenceSince(0))
-		acquired, diagnostics := acquireUnderlayGroupScopes(group, index+1, request.protectionVersion(), accounting, input.versionState, acquisitionPolicy{
-			importDefaults: request.importDefaults, sequencePolicy: request.sequencePolicy, importLimits: defaultImportLimits(),
-		})
+		acquired, diagnostics := acquireUnderlayGroupScopes(group, index+1, request.protectionVersion(), state, policy)
 		mergeResourceContexts(&input.contexts, acquired.contexts)
 		if len(diagnostics) != 0 {
 			input.sources = append(input.sources, acquired.sources...)
@@ -104,7 +102,7 @@ func assembleLayeredInput[T any](request loadRequest[T], input assembledInput, a
 			// Source-local checks still run during acquisition above.
 			protectionRule = nil
 		}
-		composition, diagnostics := composeUnderlayGroup(acquired, protectionRule, request.sequencePolicy, lower)
+		composition, diagnostics := composeUnderlayGroup(acquired, protectionRule, policy.sequencePolicy, lower)
 		sourceStart := len(input.sources)
 		input.sources = append(input.sources, acquired.sources...)
 		if len(diagnostics) != 0 {
@@ -120,7 +118,7 @@ func assembleLayeredInput[T any](request loadRequest[T], input assembledInput, a
 				}
 				operations, diagnostics := assembly.applyOverlayWithCollectionProjection(
 					composition.root, composition.origins, composition.collectionPolicies, composition.applications, LayerUnderlay,
-					request.sequencePolicy, declarations,
+					policy.sequencePolicy, declarations,
 				)
 				if len(diagnostics) != 0 {
 					return input, diagnostics
@@ -138,7 +136,7 @@ func assembleLayeredInput[T any](request loadRequest[T], input assembledInput, a
 			lower = assembly.current.collectionPolicies
 		}
 		var diagnostics []Diagnostic
-		mainComposition, diagnostics = compositionForInputWithPolicies(input, lower, request.sequencePolicy)
+		mainComposition, diagnostics = compositionForInputWithPolicies(input, lower, policy.sequencePolicy)
 		if len(diagnostics) != 0 {
 			return input, diagnostics
 		}
@@ -167,7 +165,7 @@ func assembleLayeredInput[T any](request loadRequest[T], input assembledInput, a
 			}
 			operations, diagnostics := assembly.applyOverlayWithCollectionProjection(
 				mainComposition.root, mainComposition.origins, mainComposition.collectionPolicies, mainComposition.applications, LayerBase,
-				request.sequencePolicy, declarations,
+				policy.sequencePolicy, declarations,
 			)
 			if len(diagnostics) != 0 {
 				return input, append(versionDiagnostics, diagnostics...)
@@ -191,15 +189,15 @@ func assembleLayeredInput[T any](request loadRequest[T], input assembledInput, a
 	if assembly == nil {
 		return input, versionDiagnostics
 	}
-	assembly.current.inputBytes = accounting.bytes
-	assembly.current.inputNodes = accounting.nodes
+	assembly.current.inputBytes = state.accounting.bytes
+	assembly.current.inputNodes = state.accounting.nodes
 	if activeOverlay(request.overlay) {
 		// The selected overlay context is independent of the main input. This
 		// synthetic descriptor creates no source record or input contribution.
 		selection := Source{kind: sourceBytes}
 		selected := parsedSource{document: &document.Node{Kind: document.Mapping}, source: &SourceInfo{}}
 		var diagnostics []Diagnostic
-		overlayPolicy := []sequencePolicy{request.sequencePolicy}
+		overlayPolicy := []sequencePolicy{policy.sequencePolicy}
 		input.sources, diagnostics = loadSelectedOverlayIntoWithVersion(selection, request.overlayFilesystem, selected, assembly, input.sources, request.overlay, request.protectionVersion(), defaultImportLimits(), input.versionState, overlayPolicy...)
 		if len(diagnostics) != 0 {
 			return input, append(versionDiagnostics, diagnostics...)
@@ -215,10 +213,9 @@ func assembleLayeredInput[T any](request loadRequest[T], input assembledInput, a
 	return input, versionDiagnostics
 }

-func acquireUnderlayGroupScopes(group loadGroup, index int, rule *VersionRule, accounting *importAccounting, versionState *sourceVersionState, policy acquisitionPolicy) (*acquiredUnderlayGroup, []Diagnostic) {
-	initialBytes, initialNodes := accounting.bytes, accounting.nodes
-	visited := make(map[resourceIdentity]importRoute)
-	hostToken := &namespaceToken{}
+func acquireUnderlayGroupScopes(group loadGroup, index int, rule *VersionRule, state *acquisitionState, policy acquisitionPolicy) (*acquiredUnderlayGroup, []Diagnostic) {
+	initialBytes, initialNodes := state.accounting.bytes, state.accounting.nodes
+	tier := &tierAcquisitionState{visited: make(map[resourceIdentity]importRoute), hostToken: &namespaceToken{}}
 	nativeAnchors := make(map[*namespaceToken]string)
 	for inputIndex, contribution := range group.inputs {
 		if token := nativeTokenForLoadInput(contribution); token != nil {
@@ -230,14 +227,10 @@ func acquireUnderlayGroupScopes(group loadGroup, index int, rule *VersionRule, a
 	acquiredGroup := &acquiredUnderlayGroup{index: index}
 	inclusionGraph := newImportInclusionGraph()
 	for inputIndex, contribution := range group.inputs {
-		options := Options[struct{}]{
-			Imports: contribution.imports, Filesystem: contribution.filesystem,
-			Definition: Definition[struct{}]{Version: rule}, destination: contribution.destination.clone(),
-			placementMode: contribution.placementMode, sequencePolicy: policy.sequencePolicy, deferAssembly: true,
-			directiveContext: rootDirectiveContextLayered,
-			importDefaults:   snapshotImportDefaults(policy.importDefaults),
-		}
-		acquired, diagnostics := assembleBaseInputTrackedForRole(contribution.source, options, contribution.destination, accounting, visited, hostToken, versionState, sourceVersionContribution)
+		acquired, diagnostics := acquireInput(inputAcquisitionRequest{
+			input: contribution, role: sourceVersionContribution,
+			directiveContext: rootDirectiveContextLayered, protectionRule: rule, deferAssembly: true,
+		}, policy, state, tier)
 		for _, source := range acquired.sources {
 			source.Layer = LayerUnderlay
 			source.UnderlayIndex = index
@@ -271,8 +264,8 @@ func acquireUnderlayGroupScopes(group loadGroup, index int, rule *VersionRule, a
 		mergeImportInclusionGraph(&inclusionGraph, inputGraph)
 	}
 	acquiredGroup.importGraph = inclusionGraph.clone()
-	acquiredGroup.inputBytes = accounting.bytes - initialBytes
-	acquiredGroup.inputNodes = accounting.nodes - initialNodes
+	acquiredGroup.inputBytes = state.accounting.bytes - initialBytes
+	acquiredGroup.inputNodes = state.accounting.nodes - initialNodes
 	return acquiredGroup, nil
 }

--- a/internal/engine/load_request_test.go
+++ b/internal/engine/load_request_test.go
@@ -80,7 +80,8 @@ func TestUnderlayGroupAcquisitionRetainsScopesUntilComposition(t *testing.T) {
 	})
 	accounting := &importAccounting{}
 	group := loadGroup{inputs: []loadInput{{source: filesystem.File("main.yml"), imports: true}}}
-	acquired, diagnostics := acquireUnderlayGroupScopes(group, 2, nil, accounting, nil, acquisitionPolicy{importLimits: defaultImportLimits()})
+	state := &acquisitionState{accounting: accounting}
+	acquired, diagnostics := acquireUnderlayGroupScopes(group, 2, nil, state, acquisitionPolicy{importLimits: defaultImportLimits()})
 	if len(diagnostics) != 0 {
 		t.Fatalf("acquire underlay group: %#v", diagnostics)
 	}
@@ -108,7 +109,7 @@ func TestUnderlayGroupAcquisitionRetainsScopesUntilComposition(t *testing.T) {
 		t.Fatalf("composed group handoff = %#v", composition)
 	}

-	empty, diagnostics := acquireUnderlayGroupScopes(loadGroup{}, 3, nil, accounting, nil, acquisitionPolicy{importLimits: defaultImportLimits()})
+	empty, diagnostics := acquireUnderlayGroupScopes(loadGroup{}, 3, nil, state, acquisitionPolicy{importLimits: defaultImportLimits()})
 	if len(diagnostics) != 0 || len(empty.scopes) != 0 {
 		t.Fatalf("empty group acquisition = %#v, %#v", empty, diagnostics)
 	}
@@ -469,7 +470,8 @@ func TestGroupedLoadStrictConflictsRepetitionAndBudgets(t *testing.T) {
 }

 func testAcquireUnderlayGroup(group loadGroup, index int, rule *VersionRule, accounting *importAccounting) (*composedDocument, []SourceInfo, map[string]ResourceContext, []Diagnostic) {
-	acquired, diagnostics := acquireUnderlayGroupScopes(group, index, rule, accounting, nil, acquisitionPolicy{importLimits: defaultImportLimits()})
+	state := &acquisitionState{accounting: accounting}
+	acquired, diagnostics := acquireUnderlayGroupScopes(group, index, rule, state, acquisitionPolicy{importLimits: defaultImportLimits()})
 	if len(diagnostics) != 0 {
 		return nil, acquired.sources, acquired.contexts, diagnostics
 	}