Expose invariant IDs as an extension on IssueComponent

src/Firely.Fhir.Validation/Impl/BindingValidator.cs

@@ -146,11 +146,11 @@ private ResultReport verifyContentRequirements(PocoNode source, DataType bindabl
                 case Coding cd when string.IsNullOrEmpty(cd.Code) && Strength == BindingStrength.Required:
                 case CodeableConcept cc when !codeableConceptHasCode(cc) && Strength == BindingStrength.Required:
                     return new IssueAssertion(Issue.TERMINOLOGY_INCOMPLETE_CODE_ERROR,
-                        $"No code found in {source.Poco.TypeName} with a required binding to valueset '{ValueSetUri}'.").AsResult(s, source, nameof(BindingValidator));
+                        $"No code found in {source.Poco.TypeName} with a required binding to valueset '{ValueSetUri}'.").AsResult(s, source, nameof(BindingValidator), this);
                 case CodeableConcept cc when !codeableConceptHasCode(cc) && string.IsNullOrEmpty(cc.Text) &&
                                 Strength == BindingStrength.Extensible:
                     return new IssueAssertion(Issue.TERMINOLOGY_INCOMPLETE_CODE_WARNING,
-                        $"Extensible binding to valueset '{ValueSetUri}' requires code or text.").AsResult(s, source, nameof(BindingValidator));
+                        $"Extensible binding to valueset '{ValueSetUri}' requires code or text.").AsResult(s, source, nameof(BindingValidator), this);
                 default:
                     return ResultReport.SUCCESS;      // nothing wrong then
             }
@@ -196,7 +196,8 @@ ValidateCodeParameters buildParams()
             return result switch
             {
                 (null, _) => ResultReport.SUCCESS,
-                ({ } issue, var message) => new IssueAssertion(issue, (issue.Severity == OperationOutcome.IssueSeverity.Error ? message! + ", but the binding is of strength 'required'" : message!)).AsResult(s, input, nameof(BindingValidator))
+                ({ } issue, var message) => new IssueAssertion(issue, (issue.Severity == OperationOutcome.IssueSeverity.Error ? message! + ", but the binding is of strength 'required'" : message!))
+                    .AsResult(s, input, nameof(BindingValidator), this)
             };
         }
 

src/Firely.Fhir.Validation/Impl/CanonicalValidator.cs

@@ -39,10 +39,10 @@ ResultReport IValidatable.Validate(PocoNode input, ValidationSettings vc, Valida
                 return canonical.HasAnchor || canonical.IsAbsolute
                     ? ResultReport.SUCCESS
                     : new IssueAssertion(Issue.CONTENT_ELEMENT_INVALID_PRIMITIVE_VALUE,
-                        $"Canonical URLs must be absolute URLs if they are not fragment references").AsResult(state, input, nameof(CanonicalValidator));
+                        $"Canonical URLs must be absolute URLs if they are not fragment references").AsResult(state, input, nameof(CanonicalValidator), this);
 
             return new IssueAssertion(Issue.CONTENT_ELEMENT_INVALID_PRIMITIVE_VALUE,
-                $"Primitive does not have the correct type ({input.Poco.TypeName})").AsResult(state, input, nameof(CanonicalValidator));
+                $"Primitive does not have the correct type ({input.Poco.TypeName})").AsResult(state, input, nameof(CanonicalValidator), this);
         }
     }
 }

src/Firely.Fhir.Validation/Impl/CardinalityValidator.cs

@@ -101,7 +101,7 @@ ResultReport IGroupValidatable.Validate(IEnumerable<PocoNode> input, ValidationS
 
         private ResultReport buildResult(PocoNode parent, string elemName, int count, ValidationState s) => !inRange(count) ?
                         new IssueAssertion(Issue.CONTENT_INCORRECT_OCCURRENCE,
-                        $"Instance count at element '{elemName}' is {count}, which is not within the specified cardinality of {CardinalityDisplay}").AsResult(s, parent, nameof(CardinalityValidator))
+                        $"Instance count at element '{elemName}' is {count}, which is not within the specified cardinality of {CardinalityDisplay}").AsResult(s, parent, nameof(CardinalityValidator), this)
                         : ResultReport.SUCCESS;
 
         /// <inheritdoc />

src/Firely.Fhir.Validation/Impl/ChildrenValidator.cs

@@ -100,7 +100,7 @@ ResultReport IValidatable.Validate(PocoNode input, ValidationSettings vc, Valida
             {
                 var elementList = string.Join(",", matchResult.UnmatchedInstanceElements.Select(e => $"'{e.Name}'"));
                 evidence.Add(new IssueAssertion(Issue.CONTENT_ELEMENT_HAS_UNKNOWN_CHILDREN, $"Encountered unknown child elements {elementList}")
-                    .AsResult(state, input, nameof(ChildrenValidator)));
+                    .AsResult(state, input, nameof(ChildrenValidator), this));
             }
 
             evidence.AddRange(

src/Firely.Fhir.Validation/Impl/ExtensionContextValidator.cs

@@ -27,6 +27,7 @@ namespace Firely.Fhir.Validation;
 #endif
 public class ExtensionContextValidator : IValidatable
 {
+    private const string CONTEXT_INVARIANT_KEY = "ctx-inv";
     /// <summary>
     /// Creates a new ExtensionContextValidator with the given allowed contexts and invariants.
     /// </summary>
@@ -69,7 +70,7 @@ public ResultReport Validate(PocoNode input, ValidationSettings vc, ValidationSt
         {
             return new IssueAssertion(Issue.CONTENT_INCORRECT_OCCURRENCE,
                     $"Extension used outside of appropriate contexts. Expected context to be one of: {RenderExpectedContexts}")
-                .AsResult(state, input, nameof(ExtensionContextValidator));
+                .AsResult(state, input, nameof(ExtensionContextValidator), this);
         }
 
         var invariantResults = Invariants
@@ -86,9 +87,8 @@ public ResultReport Validate(PocoNode input, ValidationSettings vc, ValidationSt
                 {
                     // If eval to false, throw an error
                     (false, null) =>
-                        new IssueAssertion(
-                            Issue.CONTENT_ELEMENT_FAILS_ERROR_CONSTRAINT,
-                            $"Extension context failed invariant constraint {res.Invariant}").AsResult(state, input, nameof(ExtensionContextValidator)),
+                        new IssueAssertion(Issue.CONTENT_ELEMENT_FAILS_ERROR_CONSTRAINT, $"Extension context failed invariant constraint {res.Invariant}")
+                            .AsResult(state, input, nameof(ExtensionContextValidator), new FhirPathValidator(res.Invariant ?? CONTEXT_INVARIANT_KEY, "")),
                     // If evalutation threw an exception, return that exception
                     (_, { } report) => report,
                     // Otherwise return success
@@ -287,7 +287,7 @@ private static InvariantValidator.InvariantResult runContextInvariant(PocoNode i
     {
         // our invariant is defined with %extension, but the FhirPathValidator expects %%extension because that is our syntax for environment variables
         // TODO investigate changing this in the SDK
-        var fhirPathValidator = new FhirPathValidator("ctx-inv", invariant.Replace("%extension", "%%extension"));
+        var fhirPathValidator = new FhirPathValidator(CONTEXT_INVARIANT_KEY, invariant.Replace("%extension", "%%extension"));
         return fhirPathValidator.RunInvariant(input.ToPocoNode().Parent!, vc, state, ("extension", [input.ToPocoNode()]));
     }
 

src/Firely.Fhir.Validation/Impl/ExtensionSchema.cs

@@ -98,7 +98,7 @@ internal override ResultReport ValidateInternal(IEnumerable<PocoNode> input, Val
 
                             evidence.Add(new ResultReport(vr,
                                 new IssueAssertion(issue, $"Unable to resolve reference to extension '{group.Key}'.")
-                                    .AsResult(state, group.First(), nameof(ExtensionSchema)).Evidence));
+                                    .AsResult(state, group.First(), nameof(ExtensionSchema), this).Evidence));
 
                             // No url available - validate the Extension schema itself.
                             evidence.Add(ValidateExtensionSchema(group, vc, state));

src/Firely.Fhir.Validation/Impl/FhirPathValidator.cs

@@ -129,7 +129,7 @@ private InvariantResult runInvariantInternal(PocoNode input, ValidationSettings
             {
                 return new(false, new IssueAssertion(Issue.PROFILE_ELEMENTDEF_INVALID_FHIRPATH_EXPRESSION,
                         $"Evaluation of FhirPath for constraint '{Key}' failed: {e.Message}")
-                    .AsResult(s, input, nameof(FhirPathValidator)));
+                    .AsResult(s, input, nameof(FhirPathValidator), this));
             }
         }
 

src/Firely.Fhir.Validation/Impl/FhirStringValidator.cs

@@ -28,10 +28,10 @@ ResultReport IValidatable.Validate(PocoNode input, ValidationSettings vc, Valida
         {
             if (input is not PrimitiveNode { Primitive: FhirString str })
                 return new IssueAssertion(Issue.CONTENT_ELEMENT_INVALID_PRIMITIVE_VALUE,
-                    $"Primitive does not have the correct type ({input.Poco.TypeName})").AsResult(state, input, nameof(FhirStringValidator));
+                    $"Primitive does not have the correct type ({input.Poco.TypeName})").AsResult(state, input, nameof(FhirStringValidator), this);
             if (!str.HasValidValue())
                 return new IssueAssertion(Issue.CONTENT_ELEMENT_INVALID_PRIMITIVE_VALUE,
-                    $"String values cannot be empty").AsResult(state, input, nameof(FhirStringValidator));
+                    $"String values cannot be empty").AsResult(state, input, nameof(FhirStringValidator), this);
             return ResultReport.SUCCESS;
         }
     }

src/Firely.Fhir.Validation/Impl/FhirTxt1Validator.cs

@@ -50,7 +50,7 @@ internal override InvariantResult RunInvariant(PocoNode input, ValidationSetting
             if (primitive is not {Poco: XHtml xhtml})
                 return new(false, 
                     new IssueAssertion(Issue.CONTENT_ELEMENT_INVALID_PRIMITIVE_VALUE,
-                        $"Narrative should be of type string, but is of type ({primitive.Poco.GetType()})").AsResult(state, input));
+                        $"Narrative should be of type string, but is of type ({primitive.Poco.GetType()})").AsResult(state, input, nameof(FhirTxt1Validator), this));
 
             // Check if the narrative contains only the basic HTML formatting elements and attributesvar result = XHtml.IsValidNarrativeXhtml(input.Value.ToString()!, out var malformedError, out var narrativeIssues);
 
@@ -63,8 +63,8 @@ internal override InvariantResult RunInvariant(PocoNode input, ValidationSetting
             else
             {
                 var issueReports = malformedError is null 
-                    ? narrativeIssues.Select(e => new IssueAssertion(Issue.XSD_VALIDATION_ERROR, e).AsResult(state, input)).ToArray()
-                    : [new IssueAssertion(Issue.XSD_VALIDATION_ERROR, malformedError).AsResult(state, input)];
+                    ? narrativeIssues.Select(e => new IssueAssertion(Issue.XSD_VALIDATION_ERROR, e).AsResult(state, input, nameof(FhirTxt1Validator), this)).ToArray()
+                    : [new IssueAssertion(Issue.XSD_VALIDATION_ERROR, malformedError).AsResult(state, input, nameof(FhirTxt1Validator), this)];
                 return new(false, ResultReport.Combine(issueReports));
             }
         }

src/Firely.Fhir.Validation/Impl/FhirTypeLabelValidator.cs

@@ -54,7 +54,7 @@ internal override ResultReport BasicValidate(PocoNode input, ValidationSettings
                 ResultReport.SUCCESS :
                 new IssueAssertion(Issue.CONTENT_ELEMENT_HAS_INCORRECT_TYPE,
                     $"The declared type of the element ({Label}) is incompatible with that of the instance ({input.Poco.TypeName}).")
-                    .AsResult(s, input, nameof(FhirTypeLabelValidator));
+                    .AsResult(s, input, nameof(FhirTypeLabelValidator), this);
             //
             return result;
         }

src/Firely.Fhir.Validation/Impl/FhirUriValidator.cs

@@ -21,7 +21,7 @@ public class FhirUriValidator : BasicValidator
 {
     internal override ResultReport BasicValidate(PocoNode input, ValidationSettings vc, ValidationState state) => 
         (input is PrimitiveNode {Poco: FhirUri uri}) 
-            ? uri.HasValidValue() && !string.IsNullOrWhiteSpace(uri.Value) ? ResultReport.SUCCESS : new IssueAssertion(Issue.CONTENT_ELEMENT_INVALID_PRIMITIVE_VALUE, $"Value '{uri}' is not a valid URI").AsResult(state, input, nameof(FhirUriValidator))
+            ? uri.HasValidValue() && !string.IsNullOrWhiteSpace(uri.Value) ? ResultReport.SUCCESS : new IssueAssertion(Issue.CONTENT_ELEMENT_INVALID_PRIMITIVE_VALUE, $"Value '{uri}' is not a valid URI").AsResult(state, input, nameof(FhirUriValidator), this)
             : ResultReport.SUCCESS; // TODO remove this check when the SDK is updated
 
     /// <inheritdoc />

src/Firely.Fhir.Validation/Impl/FixedValidator.cs

@@ -51,7 +51,7 @@ ResultReport IValidatable.Validate(PocoNode input, ValidationSettings _, Validat
             {
                 return new IssueAssertion(Issue.CONTENT_DOES_NOT_MATCH_FIXED_VALUE,
                         $"Value '{displayValue(input)}' is not exactly equal to fixed value '{displayValue(FixedValue)}'")
-                        .AsResult(s, input, nameof(FixedValidator));
+                        .AsResult(s, input, nameof(FixedValidator), this);
             }
 
             return ResultReport.SUCCESS;

src/Firely.Fhir.Validation/Impl/InvariantValidator.cs

@@ -87,7 +87,8 @@ ResultReport IValidatable.Validate(PocoNode input, ValidationSettings vc, Valida
                 return new IssueAssertion(sev == IssueSeverity.Error ?
                         Issue.CONTENT_ELEMENT_FAILS_ERROR_CONSTRAINT :
                         Issue.CONTENT_ELEMENT_FAILS_WARNING_CONSTRAINT,
-                        $"Instance failed constraint {getDescription()}").AsResult(s, input, nameof(InvariantValidator));
+                        $"Instance failed constraint {getDescription()}").AsResult(s, input, nameof(InvariantValidator),
+                        this);
             }
             else
                 return ResultReport.SUCCESS;

src/Firely.Fhir.Validation/Impl/IssueAssertion.cs

@@ -6,15 +6,13 @@
  * available at https://github.com/FirelyTeam/firely-validator-api/blob/main/LICENSE
  */
 
-using Hl7.Fhir.ElementModel;
 using Hl7.Fhir.Model;
 using Hl7.Fhir.Serialization;
 using Hl7.Fhir.Support;
 using Hl7.Fhir.Utility;
 using Newtonsoft.Json.Linq;
 using System;
 using System.Collections.Generic;
-using System.Runtime.CompilerServices;
 using System.Runtime.Serialization;
 using static Hl7.Fhir.Model.OperationOutcome;
 
@@ -88,6 +86,11 @@ public class IssueAssertion : IFixedResult, IValidatable, IEquatable<IssueAssert
     /// </summary>
     internal string? IssueSource { get; private set; }
 
+    /// <summary>
+    /// An assertion that resulted in the raised issue.
+    /// </summary>
+    internal IAssertion? Assertion { get; private set; }
+
     /// <summary>
     /// Interprets the <see cref="IssueSeverity" /> of the assertion as a <see cref="ValidationResult" />
     /// to be used by the validator for deriving the result of the validation.
@@ -125,7 +128,7 @@ public IssueAssertion(int issueNumber, string message, IssueSeverity severity, I
     {
     }
 
-    private IssueAssertion(int issueNumber, string? location, DefinitionPath? definitionPath, string message, IssueSeverity severity, IssueType? type = null, IPositionInfo? positionInfo = null, string? issueSource = null)
+    private IssueAssertion(int issueNumber, string? location, DefinitionPath? definitionPath, string message, IssueSeverity severity, IssueType? type = null, IPositionInfo? positionInfo = null, string? issueSource = null, IAssertion? assertion = null)
     {
         IssueNumber = issueNumber;
         Location = location;
@@ -135,6 +138,7 @@ private IssueAssertion(int issueNumber, string? location, DefinitionPath? defini
         Type = type;
         PositionInfo = positionInfo;
         IssueSource = issueSource;
+        Assertion = assertion;
     }
 
     /// <inheritdoc />
@@ -190,7 +194,7 @@ ResultReport IValidatable.Validate(PocoNode input, ValidationSettings _, Validat
             // Also, we replace some "magic" tags in the message with common runtime data
             var message = Message.Replace(Pattern.INSTANCETYPE, input.Poco.TypeName).Replace(Pattern.RESOURCEURL, state.Instance.ResourceUrl);
 
-        return new IssueAssertion(IssueNumber, message, Severity, Type).AsResult(state, input, IssueSource);
+        return new IssueAssertion(IssueNumber, message, Severity, Type).AsResult(state, input, IssueSource, this);
     }
 
     /// <summary>
@@ -200,7 +204,8 @@ ResultReport IValidatable.Validate(PocoNode input, ValidationSettings _, Validat
     /// <param name="input"></param>
     /// <returns></returns>
 #pragma warning disable CS0618 // Type or member is obsolete
-    public ResultReport AsResult(ValidationState state, PocoNode input) => asResult(input.GetLocation(), state.Location.DefinitionPath);
+    public ResultReport AsResult(ValidationState state, PocoNode input) 
+        => AsResult(state, input, issueSource: null, assertion: null);
 
     /// <summary>
     /// Package this <see cref="IssueAssertion"/> as a <see cref="ResultReport"/>, adding information from the current state of <paramref name="instance"/>.
@@ -209,17 +214,33 @@ ResultReport IValidatable.Validate(PocoNode input, ValidationSettings _, Validat
     /// <param name="instance"></param>
     /// <param name="issueSource"></param>
     /// <returns></returns>
-    public ResultReport AsResult(ValidationState state, PocoNode instance, string? issueSource)
+    public ResultReport AsResult(ValidationState state, PocoNode instance, string? issueSource) 
+        => AsResult(state, instance, issueSource, assertion: null);
+
+    /// <summary>
+    /// Package this <see cref="IssueAssertion"/> as a <see cref="ResultReport"/>, adding information from the current
+    /// state of <paramref name="instance"/>, and registering a callback that will be invoked with the
+    /// <see cref="IssueComponent"/> generated from this assertion when it is turned into an
+    /// <see cref="OperationOutcome"/> (e.g. to add extensions), without coupling this class to that concern.
+    /// </summary>
+    /// <param name="state"></param>
+    /// <param name="instance"></param>
+    /// <param name="issueSource"></param>
+    /// <param name="assertion">A callback invoked with the generated <see cref="IssueComponent"/>
+    /// when this assertion is turned into an <see cref="OperationOutcome"/>.</param>
+    /// <returns></returns>
+    public ResultReport AsResult(ValidationState state, PocoNode instance, string? issueSource, IAssertion? assertion)
     {
         this.PositionInfo ??= ((IAnnotated)instance).Annotation<JsonSerializationDetails>();
         this.PositionInfo ??= ((IAnnotated)instance).Annotation<XmlSerializationDetails>();
         this.PositionInfo ??= ((IAnnotated)instance).Annotation<PositionInfo>();
 
         this.IssueSource = issueSource;
-
+        this.Assertion = assertion;
+
         return asResult(instance.GetLocation(), state.Location.DefinitionPath);
     }
-    
+
 #pragma warning restore CS0618 // Type or member is obsolete
 
     /// <summary>
@@ -231,7 +252,7 @@ public ResultReport AsResult(ValidationState state, PocoNode instance, string? i
     /// Package this <see cref="IssueAssertion"/> as a <see cref="ResultReport"/>
     /// </summary>
     internal ResultReport asResult(string location, DefinitionPath? definitionPath) =>
-        new(Result, new IssueAssertion(IssueNumber, location, definitionPath, Message, Severity, Type, PositionInfo, IssueSource));
+        new(Result, new IssueAssertion(IssueNumber, location, definitionPath, Message, Severity, Type, PositionInfo, IssueSource, Assertion));
 
     /// <inheritdoc/>
     public override bool Equals(object? obj) => Equals(obj as IssueAssertion);

src/Firely.Fhir.Validation/Impl/MaxLengthValidator.cs

@@ -61,7 +61,7 @@ internal override ResultReport BasicValidate(PocoNode input, ValidationSettings
             {
                 return str.Length > MaximumLength
                     ? new IssueAssertion(Issue.CONTENT_ELEMENT_VALUE_TOO_LONG,
-                        $"Value '{str}' is too long (maximum length is {MaximumLength})").AsResult(s, input, nameof(MaxLengthValidator))
+                        $"Value '{str}' is too long (maximum length is {MaximumLength})").AsResult(s, input, nameof(MaxLengthValidator), this)
                     : ResultReport.SUCCESS;
             }
             else