From 1f6912d3a6adbcc4c162589625a1bc6034407fef Mon Sep 17 00:00:00 2001
From: Grahame Grieve <grahameg@gmail.ccom>
Date: Sat, 8 Jul 2023 16:44:50 +1000
Subject: [PATCH] fix issue checking invariant expressions in R5

---
 .../type/StructureDefinitionValidator.java    | 34 ++++++++++---------
 1 file changed, 18 insertions(+), 16 deletions(-)

diff --git a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java
index 63b978c42..1f950a540 100644
--- a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java
+++ b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/instance/type/StructureDefinitionValidator.java
@@ -485,23 +485,25 @@ public class StructureDefinitionValidator extends BaseValidator {
     String source = invariant.getNamedChildValue("source");
     if (warning(errors, "2023-06-19", IssueType.INFORMATIONAL, stack, !Utilities.noString(key), I18nConstants.ED_INVARIANT_NO_KEY)) {
       if (hint(errors, "2023-06-19", IssueType.INFORMATIONAL, stack, !Utilities.noString(expression) || VersionUtilities.isR5Plus(context.getVersion()), I18nConstants.ED_INVARIANT_NO_EXPRESSION, key)) { // not for R5 - there's an invariant
-        if (invariantMap.containsKey(key)) {
-          // it's legal - and common - for a list of elemnts to contain the same invariant more than once, but it's not valid if it's not always the same 
-          ok = rule(errors, "2023-06-19", IssueType.INVALID, stack, expression.equals(invariantMap.get(key)) || "ele-1".equals(key), I18nConstants.ED_INVARIANT_EXPRESSION_CONFLICT, key, expression, invariantMap.get(key));
-        } else {
-          invariantMap.put(key, expression);
+        if (!Utilities.noString(expression)) {
+          if (invariantMap.containsKey(key)) {
+            // it's legal - and common - for a list of elemnts to contain the same invariant more than once, but it's not valid if it's not always the same 
+            ok = rule(errors, "2023-06-19", IssueType.INVALID, stack, expression.equals(invariantMap.get(key)) || "ele-1".equals(key), I18nConstants.ED_INVARIANT_EXPRESSION_CONFLICT, key, expression, invariantMap.get(key));
+          } else {
+            invariantMap.put(key, expression);
+          }
+          if (Utilities.noString(source) || (source.equals(profileUrl))) { // no need to revalidate FHIRPath from elsewhere 
+            try {
+              //           String upath = profileUrl+"#"+path;
+              fpe.check(invariant, rootPath, path, fpe.parse(expression));
+            } catch (Exception e) {
+              if (debug) {
+                e.printStackTrace();
+              }
+              ok = rule(errors, "2023-06-19", IssueType.INVALID, stack, false, I18nConstants.ED_INVARIANT_EXPRESSION_ERROR, key, expression, e.getMessage()) && ok;
+            }         
+          }        
         }
-        if (Utilities.noString(source) || (source.equals(profileUrl))) { // no need to revalidate FHIRPath from elsewhere 
-         try {
-//           String upath = profileUrl+"#"+path;
-           fpe.check(invariant, rootPath, path, fpe.parse(expression));
-         } catch (Exception e) {
-           if (debug) {
-             e.printStackTrace();
-           }
-           ok = rule(errors, "2023-06-19", IssueType.INVALID, stack, false, I18nConstants.ED_INVARIANT_EXPRESSION_ERROR, key, expression, e.getMessage()) && ok;
-         }         
-        }        
       }
     }
     return ok;