Expose source version modes in load options

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Implement shared source version checks
 
-Status: Stages 1–7 complete; public load-wide mode integration has not started.
+Status: Stages 1–8 complete; evidence sensitivity classification has not started.
 
 Audience: a Luna coding agent implementing one numbered stage per prompt, in
 order. The [feature roadmap](source-version-checks.md) owns target behavior and
@@ -451,6 +451,24 @@ No environmental limitation affected validation; checks ran on Linux/amd64.
 Validate: facade version/layered/source and boundary tests; everyday check.
 Done: both supported public load APIs expose the implemented modes.
 
+Completion evidence: added the root-owned `SourceVersionMode` enum and constants
+to ordinary and layered options, with Go documentation for zero-value behavior,
+source-local declaration paths, destination-prefixed main protection, and the
+two enabled policies. The facade converts explicitly through the internal
+engine boundary, which keeps its mode type private and preserves unknown values
+for option validation before acquisition. Added external-package coverage for
+enabled ordinary and layered loads using byte, file, and mapping sources; zero
+mode compatibility; invalid modes and missing rules before reader access; and
+reusing one Definition with different modes. Source evidence remains private.
+These checks passed with Go `go1.26.8 linux/amd64`:
+
+- `GOTOOLCHAIN=local GOPROXY=off go test . -run 'SourceVersionMode|Version|Layered|SourceInfo|Destination|PublicFacadeBoundary|DependencyImportBoundary' -count=1`
+- `GOTOOLCHAIN=local GOPROXY=off go test ./internal/engine -run 'SourceVersion|Version|Layered|Source|Destination|Import' -count=1`
+- `GOTOOLCHAIN=local ./scripts/check.sh`
+- `git diff --check`
+
+No environmental limitation affected validation; checks ran on Linux/amd64.
+
 ## Stage 9 — Classify evidence at original paths and ancestors
 
 1. Include declaration paths/ancestors in final classification candidates,

facade_source_version_mode_test.go

@@ -0,0 +1,175 @@
+package configkit_test
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+)
+
+type sourceVersionModeReader struct {
+	*strings.Reader
+	reads int
+}
+
+func (reader *sourceVersionModeReader) Read(data []byte) (int, error) {
+	reader.reads++
+	return reader.Reader.Read(data)
+}
+
+func TestFacadeSourceVersionModesAcrossOrdinaryAndLayeredLoads(t *testing.T) {
+	t.Parallel()
+
+	var checked []configkit.Version
+	definition := configkit.Definition[map[string]any]{Version: &configkit.VersionRule{
+		Path: configkit.Keys("meta", "version"),
+		Check: func(version configkit.Version, _ *configkit.Validation) error {
+			checked = append(checked, version)
+			return nil
+		},
+	}}
+	ordinary, err := configkit.Load(configkit.Bytes("ordinary", []byte("meta: {version: ordinary-v}\n")), configkit.Options[map[string]any]{
+		Definition: definition, SourceVersionMode: configkit.SourceVersionModeIfPresent,
+	})
+	if err != nil || ordinary == nil {
+		t.Fatalf("ordinary enabled load = %#v, %v", ordinary, err)
+	}
+	if got := ordinary.Config["meta"].(map[string]any)["version"]; got != "ordinary-v" {
+		t.Fatalf("main declaration was not retained: %#v", ordinary.Config)
+	}
+
+	directory := t.TempDir()
+	mainPath := filepath.Join(directory, "main.yml")
+	if err := os.WriteFile(mainPath, []byte("meta: {version: main-v}\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	layered, err := configkit.LoadLayered(configkit.Input{Source: configkit.File(mainPath)}, configkit.LayeredOptions[map[string]any]{
+		Definition: definition, SourceVersionMode: configkit.SourceVersionModeRequired,
+		Underlays: []configkit.Underlay{{Inputs: []configkit.Input{{
+			Source: configkit.Mapping("underlay", map[string]any{
+				"meta": map[string]any{"version": "underlay-v"}, "fallback": "present",
+			}),
+			Destination: configkit.Keys("defaults"),
+		}}}},
+	})
+	if err != nil || layered == nil {
+		t.Fatalf("layered enabled load = %#v, %v", layered, err)
+	}
+	defaults, ok := layered.Config["defaults"].(map[string]any)
+	if !ok || defaults["fallback"] != "present" {
+		t.Fatalf("layered underlay payload = %#v", layered.Config["defaults"])
+	}
+	if meta, ok := defaults["meta"].(map[string]any); !ok || len(meta) != 0 {
+		t.Fatalf("accepted underlay declaration was not consumed: %#v", defaults["meta"])
+	}
+	if len(checked) != 3 {
+		t.Fatalf("checker calls across separate mode uses = %#v", checked)
+	}
+	for _, want := range []string{"ordinary-v", "main-v", "underlay-v"} {
+		found := false
+		for _, version := range checked {
+			found = found || version.Present && version.Text == want
+		}
+		if !found {
+			t.Errorf("checked versions %#v do not include %q", checked, want)
+		}
+	}
+}
+
+func TestFacadeSourceVersionModeZeroPreservesDefaultBehavior(t *testing.T) {
+	t.Parallel()
+
+	checks := 0
+	result, err := configkit.Load(configkit.Bytes("default", []byte("version: v1\n")), configkit.Options[map[string]any]{
+		Definition: configkit.Definition[map[string]any]{Version: &configkit.VersionRule{
+			Path: configkit.Keys("version"),
+			Check: func(version configkit.Version, _ *configkit.Validation) error {
+				checks++
+				if version != (configkit.Version{Present: true, Text: "v1"}) {
+					t.Errorf("default version = %#v", version)
+				}
+				return nil
+			},
+		}},
+	})
+	if err != nil || result == nil || result.Config["version"] != "v1" || checks != 1 {
+		t.Fatalf("zero-mode load = %#v, %v; checks = %d", result, err, checks)
+	}
+}
+
+func TestFacadeSourceVersionModeValidationPrecedesSourceReads(t *testing.T) {
+	t.Parallel()
+
+	validDefinition := configkit.Definition[map[string]any]{Version: &configkit.VersionRule{
+		Path: configkit.Keys("version"), Check: func(configkit.Version, *configkit.Validation) error { return nil },
+	}}
+	for _, test := range []struct {
+		name    string
+		mode    configkit.SourceVersionMode
+		def     configkit.Definition[map[string]any]
+		layered bool
+	}{
+		{name: "unknown ordinary mode", mode: configkit.SourceVersionMode(255), def: validDefinition},
+		{name: "ordinary mode requires checker", mode: configkit.SourceVersionModeIfPresent},
+		{name: "unknown layered mode", mode: configkit.SourceVersionMode(255), def: validDefinition, layered: true},
+		{name: "layered mode requires checker", mode: configkit.SourceVersionModeRequired, layered: true},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			reader := &sourceVersionModeReader{Reader: strings.NewReader("version: v1\n")}
+			source := configkit.Reader("version.yml", reader)
+			var err error
+			if test.layered {
+				_, err = configkit.LoadLayered(configkit.Input{Source: source}, configkit.LayeredOptions[map[string]any]{
+					Definition: test.def, SourceVersionMode: test.mode,
+				})
+			} else {
+				_, err = configkit.Load(source, configkit.Options[map[string]any]{
+					Definition: test.def, SourceVersionMode: test.mode,
+				})
+			}
+			var loadError *configkit.LoadError
+			if !errors.As(err, &loadError) || len(loadError.Diagnostics()) != 1 || loadError.Diagnostics()[0].Code != configkit.CodeOptionsInvalid {
+				t.Fatalf("invalid mode error = %#v", err)
+			}
+			if reader.reads != 0 {
+				t.Fatalf("invalid options read source %d times", reader.reads)
+			}
+		})
+	}
+}
+
+func TestFacadeSourceVersionDefinitionCanBeReusedWithDifferentModes(t *testing.T) {
+	t.Parallel()
+
+	checks := 0
+	definition := configkit.Definition[map[string]any]{Version: &configkit.VersionRule{
+		Path: configkit.Keys("version"),
+		Check: func(version configkit.Version, _ *configkit.Validation) error {
+			checks++
+			if version.Present {
+				t.Errorf("missing declaration reached checker as %#v", version)
+			}
+			return nil
+		},
+	}}
+	source := configkit.Bytes("reused", []byte("value: retained\n"))
+	ifPresent, err := configkit.Load(source, configkit.Options[map[string]any]{
+		Definition: definition, SourceVersionMode: configkit.SourceVersionModeIfPresent,
+	})
+	if err != nil || ifPresent == nil || checks != 1 {
+		t.Fatalf("if-present load = %#v, %v; checks = %d", ifPresent, err, checks)
+	}
+	required, err := configkit.Load(source, configkit.Options[map[string]any]{
+		Definition: definition, SourceVersionMode: configkit.SourceVersionModeRequired,
+	})
+	var loadError *configkit.LoadError
+	if required != nil || !errors.As(err, &loadError) || len(loadError.Diagnostics()) != 1 || loadError.Diagnostics()[0].Code != configkit.CodeVersionError {
+		t.Fatalf("required load = %#v, %v", required, err)
+	}
+	if checks != 1 {
+		t.Fatalf("required absence reached checker: calls = %d", checks)
+	}
+}

internal/engine/source_version.go

@@ -10,6 +10,13 @@ const (
 	sourceVersionModeRequired
 )
 
+// SourceVersionModeFromFacade converts the root-owned public mode while
+// keeping the engine's policy type private. Unknown values remain intact for
+// pre-acquisition validation.
+func SourceVersionModeFromFacade(value uint8) sourceVersionMode {
+	return sourceVersionMode(value)
+}
+
 type sourceVersionRole uint8
 
 const (

layered.go

@@ -23,8 +23,12 @@ type Underlay struct{ Inputs []Input }
 // LayeredOptions selects lower-priority tiers and final application rules.
 // An active Overlay requires an explicit OverlayFilesystem; an inactive overlay
 // ignores it. Overrides remain explicit CLI records, not general mappings.
+// SourceVersionMode applies one declaration policy to main, underlay, import,
+// and selected overlay documents. Enabled modes interpret the version path
+// source-locally while protecting main's destination-prefixed path.
 type LayeredOptions[T any] struct {
 	Definition        Definition[T]
+	SourceVersionMode SourceVersionMode
 	Underlays         []Underlay
 	Overlay           string
 	OverlayFilesystem *FilesystemContext
@@ -57,7 +61,9 @@ func toEngineInput(input Input) engine.Input {
 
 func toEngineLayeredOptions[T any](options LayeredOptions[T]) engine.LayeredOptions[T] {
 	result := engine.LayeredOptions[T]{
-		Definition: toEngineDefinition(options.Definition), Overlay: options.Overlay,
+		Definition:        toEngineDefinition(options.Definition),
+		SourceVersionMode: engine.SourceVersionModeFromFacade(uint8(options.SourceVersionMode)),
+		Overlay:           options.Overlay,
 		OverlayFilesystem: toEngineFilesystemContext(options.OverlayFilesystem),
 	}
 	if options.Underlays != nil {

lifecycle.go

@@ -17,15 +17,39 @@ type Definition[T any] struct {
 	Secret   func(Path) bool
 }
 
+// SourceVersionMode controls schema-version declarations across one complete
+// load. The zero value preserves the existing effective-path version check.
+type SourceVersionMode uint8
+
+const (
+	// SourceVersionModeDefault preserves the existing main-version check and
+	// rejects version-path contributions from imported, underlay, and overlay
+	// payloads.
+	SourceVersionModeDefault SourceVersionMode = iota
+	// SourceVersionModeIfPresent checks each participating document that has a
+	// declaration. A missing main declaration still reaches the checker; an
+	// absent non-main declaration skips it. Accepted non-main declarations are
+	// consumed before composition.
+	SourceVersionModeIfPresent
+	// SourceVersionModeRequired requires a declaration in each participating
+	// document. NoSource retains the existing absent-main checker behavior.
+	// Accepted non-main declarations are consumed before composition.
+	SourceVersionModeRequired
+)
+
 // Options contains the application definition and per-load input selections.
 // Imports enables explicit path and glob imports; Overlay selects one fixed overlay;
 // Overrides contains only values explicitly supplied by an application CLI.
+// Enabled source-version modes interpret Definition.Version.Path in each
+// document's local coordinates. Main protection remains at that path prefixed
+// by the main input's Destination.
 type Options[T any] struct {
-	Definition Definition[T]
-	Imports    bool
-	Overlay    string
-	Filesystem *FilesystemContext
-	Overrides  []Override
+	Definition        Definition[T]
+	Imports           bool
+	Overlay           string
+	Filesystem        *FilesystemContext
+	Overrides         []Override
+	SourceVersionMode SourceVersionMode
 }
 
 // FilesystemContext supplies roots for imports and overlays. With FS nil,
@@ -226,9 +250,10 @@ func (v *Validation) engineContext() *engine.Validation {
 
 func toEngineOptions[T any](options Options[T]) engine.Options[T] {
 	result := engine.Options[T]{
-		Definition: toEngineDefinition(options.Definition),
-		Imports:    options.Imports,
-		Overlay:    options.Overlay,
+		Definition:        toEngineDefinition(options.Definition),
+		Imports:           options.Imports,
+		Overlay:           options.Overlay,
+		SourceVersionMode: engine.SourceVersionModeFromFacade(uint8(options.SourceVersionMode)),
 	}
 	if options.Filesystem != nil {
 		result.Filesystem = toEngineFilesystemContext(options.Filesystem)