Add single-source loading and version checks

validation.go

@@ -0,0 +1,101 @@
+package configkit
+
+import "gitea.maximumdirect.net/eric/ConfigKit/internal/document"
+
+// Validation collects safe application diagnostics during a supported callback.
+// A callback must not retain the context or use it concurrently.
+type Validation struct {
+	state *validationState
+}
+
+type validationState struct {
+	active      bool
+	errorCode   Code
+	warningCode Code
+	document    *document.Node
+	diagnostics []Diagnostic
+}
+
+// Error reports a value-free application error at path. Related paths are
+// resolved to source locations when possible.
+func (v *Validation) Error(path Path, message string, related ...Path) {
+	v.report(SeverityError, path, message, related)
+}
+
+// Warning reports a value-free application warning at path. Related paths are
+// resolved to source locations when possible.
+func (v *Validation) Warning(path Path, message string, related ...Path) {
+	v.report(SeverityWarning, path, message, related)
+}
+
+func (v *Validation) report(severity Severity, path Path, message string, related []Path) {
+	if v == nil || v.state == nil || !v.state.active {
+		return
+	}
+	code := v.state.errorCode
+	if severity == SeverityWarning {
+		code = v.state.warningCode
+	}
+	diagnostic := Diagnostic{Code: code, Severity: severity, Path: path.clone(), Message: message}
+	if !path.valid() {
+		diagnostic.Severity = SeverityError
+		diagnostic.Code = v.state.errorCode
+		diagnostic.Path = Path{}
+		diagnostic.Message = "application reported an invalid configuration path"
+	} else if location, ok := nearestDocumentLocation(v.state.document, path); ok {
+		diagnostic.Primary = documentLocationPointer(location)
+	}
+	for _, relatedPath := range related {
+		if !relatedPath.valid() {
+			continue
+		}
+		if location, ok := nearestDocumentLocation(v.state.document, relatedPath); ok {
+			diagnostic.Related = append(diagnostic.Related, Location{
+				SourceID: location.SourceID, Line: location.Line, Column: location.Column,
+			})
+		}
+	}
+	v.state.diagnostics = append(v.state.diagnostics, diagnostic)
+}
+
+func nearestDocumentLocation(root *document.Node, path Path) (document.Location, bool) {
+	if root == nil || !path.valid() {
+		return document.Location{}, false
+	}
+	current := root
+	nearest := current.Location
+	for _, segment := range path.segments {
+		switch current.Kind {
+		case document.Mapping:
+			if segment.kind == pathSegmentIndex {
+				return nearest, locationKnown(nearest)
+			}
+			found := false
+			for _, entry := range current.Mapping {
+				if entry.Key == segment.key {
+					current = entry.Value
+					nearest = current.Location
+					found = true
+					break
+				}
+			}
+			if !found {
+				return nearest, locationKnown(nearest)
+			}
+		case document.Sequence:
+			index, ok := schemaIndex(segment)
+			if !ok || index >= len(current.Sequence) {
+				return nearest, locationKnown(nearest)
+			}
+			current = current.Sequence[index]
+			nearest = current.Location
+		default:
+			return nearest, locationKnown(nearest)
+		}
+	}
+	return nearest, locationKnown(nearest)
+}
+
+func locationKnown(location document.Location) bool {
+	return location.SourceID != "" || location.Line != 0 || location.Column != 0
+}