From 6b5ca97aa8c103753b930689955e3bc32d087400 Mon Sep 17 00:00:00 2001
From: Grahame Grieve <grahameg@gmail.ccom>
Date: Fri, 15 Sep 2023 12:46:45 -0700
Subject: [PATCH] Fix error in Comparisons

---
 .../fhir/r5/comparison/ComparisonSession.java |  4 +--
 .../StructureDefinitionComparer.java          | 26 +++++++++++++------
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/ComparisonSession.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/ComparisonSession.java
index 6f905935f..3c05b67dc 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/ComparisonSession.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/ComparisonSession.java
@@ -109,9 +109,9 @@ public class ComparisonSession {
           throw new FHIRException("Unable to compare resources of type "+left.fhirType()+" and "+right.fhirType());
         }
       } catch (Throwable e) {
-//        if (debug) {
+        if (debug) {
           e.printStackTrace();
-//        }
+        }
         ResourceComparer.PlaceHolderComparison csc = new ResourceComparer.PlaceHolderComparison(left, right, e);
         compares.put(key, csc);
         return csc;      
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/StructureDefinitionComparer.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/StructureDefinitionComparer.java
index 8fbc6f7b4..a4874833e 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/StructureDefinitionComparer.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/comparison/StructureDefinitionComparer.java
@@ -906,10 +906,15 @@ public class StructureDefinitionComparer extends CanonicalResourceComparer imple
             } else if (derivesFrom(sdnw, sdex, ctxt)) {
               tfound = true;
             } else if (sdnw.getSnapshot().getElement().get(0).getPath().equals(sdex.getSnapshot().getElement().get(0).getPath())) {
-              ProfileComparison compP = (ProfileComparison) session.compare(sdex, sdnw);
-              if (compP.getUnion() != null) {
-                tfound = true;
-                ex.addTargetProfile("#"+compP.getId());
+              ResourceComparison cmp = session.compare(sdex, sdnw);
+              if (cmp instanceof ProfileComparison) {
+                ProfileComparison compP = (ProfileComparison) cmp;
+                if (compP.getUnion() != null) {
+                  tfound = true;
+                  ex.addTargetProfile("#"+compP.getId());
+                }
+              } else {
+                // ?
               }
             }
           }
@@ -973,10 +978,15 @@ public class StructureDefinitionComparer extends CanonicalResourceComparer imple
               c.setProfile(r.getProfile());
               pfound = true;
             } else if (sdl.getType().equals(sdr.getType())) {
-              ProfileComparison compP = (ProfileComparison) session.compare(sdl, sdr);
-              if (compP != null && compP.getIntersection() != null) {
-                pfound = true;
-                c.addProfile("#"+compP.getId());
+              ResourceComparison cmp = session.compare(sdl, sdr);
+              if (cmp instanceof ProfileComparison) {
+                ProfileComparison compP = (ProfileComparison) cmp;
+                if (compP != null && compP.getIntersection() != null) {
+                  pfound = true;
+                  c.addProfile("#"+compP.getId());
+                }
+              } else {
+                // not sure how to handle this error?
               }
             }
           }