Compose grouped underlays in shared load lifecycle

internal/engine/load_request.go

@@ -0,0 +1,171 @@
+package engine
+
+import (
+	"gitea.maximumdirect.net/eric/ConfigKit/internal/document"
+)
+
+// loadRequest keeps source acquisition separate from precedence assembly.
+// The ordinary entry point and grouped entry point share the final lifecycle.
+type loadRequest[T any] struct {
+	main              loadInput
+	underlays         []loadGroup
+	definition        Definition[T]
+	overlay           string
+	overlayFilesystem *FilesystemContext
+	overrides         []Override
+	ordinary          bool
+}
+
+type loadInput struct {
+	source     Source
+	imports    bool
+	filesystem *FilesystemContext
+}
+
+type loadGroup struct{ inputs []loadInput }
+
+func loadGroupedWithSecretLookup[T any](request loadRequest[T], secrets SecretBinding, lookup secretLookup) (*Loaded[T], error) {
+	request.ordinary = false
+	var diagnostics []Diagnostic
+	_, mainDiagnostics := selectOptions(request.main.source, []Options[T]{{
+		Definition: request.definition, Imports: request.main.imports, Filesystem: request.main.filesystem,
+	}})
+	diagnostics = append(diagnostics, mainDiagnostics...)
+	for _, group := range request.underlays {
+		for _, input := range group.inputs {
+			_, inputDiagnostics := selectOptions(input.source, []Options[T]{{Imports: input.imports, Filesystem: input.filesystem}})
+			diagnostics = append(diagnostics, inputDiagnostics...)
+		}
+	}
+	if !validOverlayName(request.overlay) {
+		diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "overlay name must contain only ASCII letters, digits, underscore, or hyphen"))
+	}
+	if activeOverlay(request.overlay) {
+		if request.overlayFilesystem == nil {
+			diagnostics = append(diagnostics, optionDiagnostic(CodeOptionsInvalid, "selected overlay requires explicit filesystem context"))
+		} else {
+			diagnostics = append(diagnostics, filesystemOptionDiagnostics(Source{kind: sourceBytes}, request.overlayFilesystem)...)
+		}
+	}
+	if len(diagnostics) != 0 {
+		return nil, (&diagnosticAccumulator{diagnostics: canonicalDiagnostics(diagnostics)}).loadError()
+	}
+	return executeLoadRequest(request, secrets, lookup)
+}
+
+func assembleLayeredInput[T any](request loadRequest[T], input assembledInput, accounting *importAccounting) (assembledInput, []Diagnostic) {
+	groups := make([]*composedDocument, 0, len(request.underlays))
+	for index, group := range request.underlays {
+		composition, sources, diagnostics := acquireUnderlayGroup(group, index+1, request.definition.Version, accounting)
+		input.sources = append(input.sources, sources...)
+		if len(diagnostics) != 0 {
+			return input, diagnostics
+		}
+		if composition != nil {
+			groups = append(groups, composition)
+		}
+	}
+
+	var assembly *assemblyAccumulator
+	for _, group := range groups {
+		if assembly == nil {
+			assembly = newAssemblyAccumulator(group)
+			continue
+		}
+		if diagnostics := assembly.applyOverlay(group.root, group.origins, group.applications, LayerUnderlay); len(diagnostics) != 0 {
+			return input, diagnostics
+		}
+	}
+	if input.document != nil {
+		mainComposition, diagnostics := compositionForInput(input)
+		if len(diagnostics) != 0 {
+			return input, diagnostics
+		}
+		if assembly == nil {
+			assembly = newAssemblyAccumulator(mainComposition)
+		} else if diagnostics := assembly.applyOverlay(mainComposition.root, mainComposition.origins, mainComposition.applications, LayerBase); len(diagnostics) != 0 {
+			return input, diagnostics
+		}
+	}
+	if assembly == nil && (activeOverlay(request.overlay) || len(request.overrides) != 0) {
+		composition, _ := compositionForInput(assembledInput{})
+		assembly = newAssemblyAccumulator(composition)
+	}
+	if assembly == nil {
+		return input, nil
+	}
+	assembly.current.inputBytes = accounting.bytes
+	assembly.current.inputNodes = 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
+		input.sources, diagnostics = loadSelectedOverlayInto(selection, request.overlayFilesystem, selected, assembly, input.sources, request.overlay, request.definition.Version, defaultImportLimits())
+		if len(diagnostics) != 0 {
+			return input, diagnostics
+		}
+	}
+	if len(request.overrides) != 0 {
+		var diagnostics []Diagnostic
+		input.sources, diagnostics = assembly.applyOverrides(input.sources, request.overrides, request.definition.Version, defaultImportLimits())
+		if len(diagnostics) != 0 {
+			return input, diagnostics
+		}
+	}
+	input.composition = assembly.current
+	input.document = assembly.current.root
+	return input, nil
+}
+
+func acquireUnderlayGroup(group loadGroup, index int, rule *VersionRule, accounting *importAccounting) (*composedDocument, []SourceInfo, []Diagnostic) {
+	visited := make(map[resourceIdentity]importRoute)
+	hostToken := &namespaceToken{}
+	var documents []*document.Node
+	var sources []SourceInfo
+	for _, contribution := range group.inputs {
+		options := Options[struct{}]{Imports: contribution.imports, Filesystem: contribution.filesystem, Definition: Definition[struct{}]{Version: rule}}
+		acquired, diagnostics := assembleBaseInputTracked(contribution.source, options, accounting, visited, hostToken)
+		for _, source := range acquired.sources {
+			source.Layer = LayerUnderlay
+			source.UnderlayIndex = index
+			sources = append(sources, source)
+		}
+		if len(diagnostics) != 0 {
+			return nil, sources, diagnostics
+		}
+		if acquired.document == nil {
+			continue
+		}
+		if node := fragmentVersionClaim(acquired.document, rule); node != nil {
+			location := publicLocation(node.Location)
+			return nil, sources, []Diagnostic{{
+				Code: CodeUnderlayVersion, Severity: SeverityError, Path: rule.Path.clone(),
+				Message: "underlay inputs cannot contribute to the schema-version path", Primary: &location,
+			}}
+		}
+		if acquired.composition != nil {
+			for _, application := range acquired.composition.applications {
+				documents = append(documents, application.value)
+			}
+		} else {
+			documents = append(documents, acquired.document)
+		}
+	}
+	if len(documents) == 0 {
+		return nil, sources, nil
+	}
+	composition, diagnostics := composeDocuments(documents...)
+	if len(diagnostics) != 0 {
+		return nil, sources, diagnostics
+	}
+	for pointer, origin := range composition.origins {
+		origin.Layer = LayerUnderlay
+		composition.origins[pointer] = origin
+	}
+	for index := range composition.applications {
+		composition.applications[index].layer = LayerUnderlay
+	}
+	return composition, sources, nil
+}