Add semantic configuration resume evidence

internal/app/semantic_resume.go

@@ -0,0 +1,95 @@
+package app
+
+import (
+	"context"
+	"fmt"
+
+	"gitea.maximumdirect.net/eric/narratio/internal/manifest"
+	"gitea.maximumdirect.net/eric/narratio/internal/stage"
+)
+
+func currentStageSemanticConfig(selected stage.Stage, env *stage.Env) (*manifest.SemanticConfigFingerprint, error) {
+	provider, ok := selected.(stage.SemanticConfigFingerprinter)
+	if !ok {
+		return nil, nil
+	}
+	record, err := provider.SemanticConfigFingerprint(env)
+	if err != nil {
+		return nil, err
+	}
+	if err := record.Validate(); err != nil {
+		return nil, fmt.Errorf("invalid current semantic configuration fingerprint: %w", err)
+	}
+	return cloneSemanticConfig(&record), nil
+}
+
+func validateStageSemanticResume(selected stage.Stage, m *manifest.Manifest, current *manifest.SemanticConfigFingerprint) stage.ResumeValidation {
+	if current == nil {
+		return stage.Resumable()
+	}
+	var persisted *manifest.SemanticConfigFingerprint
+	if m != nil && m.Stages != nil && m.Stages[selected.Name()] != nil {
+		persisted = m.Stages[selected.Name()].SemanticConfig
+	}
+	if persisted == nil {
+		return stage.NonResumable("semantic configuration evidence is missing; rerun the stage to establish current evidence")
+	}
+	if err := persisted.Validate(); err != nil {
+		return stage.NonResumable("persisted semantic configuration evidence is malformed; rerun the stage")
+	}
+	if persisted.Version != current.Version {
+		return stage.NonResumable("semantic configuration contract version changed; rerun the stage")
+	}
+	if persisted.Digest != current.Digest {
+		return stage.NonResumable("result-affecting configuration changed; rerun the stage")
+	}
+	return stage.Resumable()
+}
+
+func evaluateStageResume(
+	ctx context.Context,
+	selected stage.Stage,
+	env *stage.Env,
+	m *manifest.Manifest,
+	current *manifest.SemanticConfigFingerprint,
+) (*stage.ResumeValidation, error) {
+	semantic := validateStageSemanticResume(selected, m, current).Normalized()
+	if !semantic.Resumable {
+		return &semantic, nil
+	}
+	validator, ok := selected.(stage.ResumeValidator)
+	if !ok {
+		if current == nil {
+			return nil, nil
+		}
+		return &semantic, nil
+	}
+	validation, err := validator.ValidateResume(ctx, env, m)
+	if err != nil {
+		return nil, err
+	}
+	validation = validation.Normalized()
+	return &validation, nil
+}
+
+func setSessionStageSemanticConfig(m *manifest.Manifest, name string, value *manifest.SemanticConfigFingerprint) {
+	if m == nil || m.Stages == nil || m.Stages[name] == nil {
+		return
+	}
+	m.Stages[name].SemanticConfig = cloneSemanticConfig(value)
+}
+
+func setRunStageSemanticConfig(m *manifest.RunManifest, name string, value *manifest.SemanticConfigFingerprint) {
+	if m == nil || m.Stages == nil || m.Stages[name] == nil {
+		return
+	}
+	m.Stages[name].SemanticConfig = cloneSemanticConfig(value)
+}
+
+func cloneSemanticConfig(value *manifest.SemanticConfigFingerprint) *manifest.SemanticConfigFingerprint {
+	if value == nil {
+		return nil
+	}
+	copy := *value
+	return &copy
+}