issue #4101 - call beforeX interceptor methods prior to checking if u…

…pdate is skippable

Previously, a skippable update (one that would not affect the contents of the resource being updated)
would result in a success without invoking beforeUpdate or beforePatch interceptor methods.

For users of fhir-smart, this behavior is confusing because the user may not have write access to this
resource type, but the server is "allowing" the write anyway (even though its being optimized away).

Signed-off-by: Lee Surprenant <lmsurpre@merative.com>

fhir-server/src/main/java/org/linuxforhealth/fhir/server/util/FHIRRestHelper.java

@@ -715,33 +715,6 @@ public FHIRRestOperationResponse doUpdateMeta(FHIRPersistenceEvent event, String
                     return ior; // early exit, before firing any update events
                 }
                 performVersionAwareUpdateCheck(ior.getPrevResource(), ifMatchValue);
-
-                // In the case of a patch, we should not be updating meaninglessly.
-                if ((skippableUpdate || patch != null) && !isDeleted) {
-                    ResourceFingerprintVisitor fingerprinter = new ResourceFingerprintVisitor();
-                    ior.getPrevResource().accept(fingerprinter);
-                    SaltHash baseline = fingerprinter.getSaltAndHash();
-
-                    fingerprinter = new ResourceFingerprintVisitor(baseline);
-                    newResource.accept(fingerprinter);
-                    if (fingerprinter.getSaltAndHash().equals(baseline)) {
-                        ior.setResource(ior.getPrevResource());
-                        ior.setStatus(Status.OK);
-                        ior.setLocationURI(FHIRUtil.buildLocationURI(type, ior.getPrevResource()));
-                        ior.setOperationOutcome(OperationOutcome.builder()
-                                .issue(Issue.builder()
-                                    .severity(IssueSeverity.INFORMATION)
-                                    .code(IssueType.INFORMATIONAL)
-                                    .details(CodeableConcept.builder()
-                                        .text(string("Update resource matches the existing resource; skipping the update"))
-                                        .build())
-                                    .build())
-                                .build());
-
-                        ior.setCompleted(true);
-                        return ior; // early exit, before firing any update events
-                    }
-                }
             }
 
             // Configure the persistence event ready to fire the "before create|update|patch" events.
@@ -764,6 +737,33 @@ public FHIRRestOperationResponse doUpdateMeta(FHIRPersistenceEvent event, String
             // capture the resource in case the interceptors modified it in some way
             newResource = event.getFhirResource();
 
+            // In the case of a patch, we should not be updating meaninglessly.
+            if ((skippableUpdate || patch != null) && !isDeleted && ior.getPrevResource() != null) {
+                ResourceFingerprintVisitor fingerprinter = new ResourceFingerprintVisitor();
+                ior.getPrevResource().accept(fingerprinter);
+                SaltHash baseline = fingerprinter.getSaltAndHash();
+
+                fingerprinter = new ResourceFingerprintVisitor(baseline);
+                newResource.accept(fingerprinter);
+                if (fingerprinter.getSaltAndHash().equals(baseline)) {
+                    ior.setResource(ior.getPrevResource());
+                    ior.setStatus(Status.OK);
+                    ior.setLocationURI(FHIRUtil.buildLocationURI(type, ior.getPrevResource()));
+                    ior.setOperationOutcome(OperationOutcome.builder()
+                            .issue(Issue.builder()
+                                .severity(IssueSeverity.INFORMATION)
+                                .code(IssueType.INFORMATIONAL)
+                                .details(CodeableConcept.builder()
+                                    .text(string("Update resource matches the existing resource; skipping the update"))
+                                    .build())
+                                .build())
+                            .build());
+
+                    ior.setCompleted(true);
+                    return ior; // early exit
+                }
+            }
+
             // update the meta in the new resource. Use the version from the previous resource - this gets checked
             // again under a database lock during the persistence phase and the request will be rejected if there's
             // a mismatch (can happen when there are concurrent updates).
@@ -1404,7 +1404,7 @@ public Bundle doSearch(String type, String compartment, String compartmentId,
             MultiResourceResult searchResult =
                     persistence.search(persistenceContext, resourceType);
             bundle = createSearchResponseBundle(searchResult.getResourceResults(), searchContext, type);
-           
+
             if (requestUri != null) {
                 bundle = addLinks(searchContext, bundle, requestUri, searchResult.geFirstId(), searchResult.getLastId(), searchResult.getExpectedNextId(), searchResult.getExpectedPreviousId());
             }
@@ -1448,7 +1448,7 @@ private String getResourceId(ResourceResult<? extends Resource> resourceResult)
             return null;
         }
         return resourceResult.getResource().getId();
-        
+
     }
 
     @Override
@@ -2570,7 +2570,7 @@ private Bundle addLinks(FHIRPagingContext context, Bundle responseBundle, String
 
                 // add the expected resource Id of the last resource in the previous page of search results as a query parameter to previous url
                 prevLinkUrl = addParameterToUrl(prevLinkUrl, SearchConstants.LAST_ID, expectedPreviousId);
-                
+
 
                 // create 'previous' link
                 Bundle.Link prevLink =
@@ -2581,7 +2581,7 @@ private Bundle addLinks(FHIRPagingContext context, Bundle responseBundle, String
 
         return bundleBuilder.build();
     }
-    
+
     /**
      * Add a new parameter with the name and value to the url.
      * @param url the url to which the parameter has to be added