Make prefab patch application use a best effort mechanism

Signed-off-by: srikappa <srikappa@amazon.com>

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Instance/InstanceToTemplatePropagator.cpp

@@ -172,20 +172,23 @@ namespace AzToolsFramework
             PrefabDom& templateDomReference = m_prefabSystemComponentInterface->FindTemplateDom(templateId);
 
             //apply patch to template
-            AZ::JsonSerializationResult::ResultCode result = AZ::JsonSerialization::ApplyPatch(templateDomReference,
-                templateDomReference.GetAllocator(), providedPatch, AZ::JsonMergeApproach::JsonPatch);
+            AZ::JsonSerializationResult::ResultCode result =
+                PrefabDomUtils::ApplyPatches(templateDomReference, templateDomReference.GetAllocator(), providedPatch);
 
             //trigger propagation
-            if (result.GetOutcome() == AZ::JsonSerializationResult::Outcomes::Success)
+            if (result.GetOutcome() != AZ::JsonSerializationResult::Outcomes::Success)
             {
-                m_prefabSystemComponentInterface->SetTemplateDirtyFlag(templateId, true);
-                m_prefabSystemComponentInterface->PropagateTemplateChanges(templateId, instanceToExclude);
-                return true;
+                AZ_Error("Prefab", false, "Patch was not successfully applied.");
+                return false; 
             }
             else
             {
-                AZ_Error("Prefab", false, "Patch was not successfully applied");
-                return false;
+                AZ_Error(
+                    "Prefab", result.GetOutcome() != AZ::JsonSerializationResult::Outcomes::PartialSkip,
+                    "Some of the patches are not successfully applied.");
+                m_prefabSystemComponentInterface->SetTemplateDirtyFlag(templateId, true);
+                m_prefabSystemComponentInterface->PropagateTemplateChanges(templateId, instanceToExclude);
+                return true;
             }
         }
 

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Link/Link.cpp

@@ -176,12 +176,17 @@ namespace AzToolsFramework
             }
             else
             {
-                AZ::JsonSerializationResult::ResultCode applyPatchResult = AZ::JsonSerialization::ApplyPatch(
-                    sourceTemplateDomCopy,
-                    targetTemplatePrefabDom.GetAllocator(),
-                    patchesReference->get(),
-                    AZ::JsonMergeApproach::JsonPatch);
+                AZ::JsonSerializationResult::ResultCode applyPatchResult =
+                    PrefabDomUtils::ApplyPatches(sourceTemplateDomCopy, targetTemplatePrefabDom.GetAllocator(), patchesReference->get());
                 linkedInstanceDom.CopyFrom(sourceTemplateDomCopy, targetTemplatePrefabDom.GetAllocator());
+
+                PrefabDomValueReference sourceTemplateName =
+                    PrefabDomUtils::FindPrefabDomValue(sourceTemplateDomCopy, PrefabDomUtils::SourceName);
+                AZ_Assert(sourceTemplateName && sourceTemplateName->get().IsString(), "A valid source template name couldn't be found");
+                PrefabDomValueReference targetTemplateName =
+                    PrefabDomUtils::FindPrefabDomValue(targetTemplatePrefabDom, PrefabDomUtils::SourceName);
+                AZ_Assert(targetTemplateName && targetTemplateName->get().IsString(), "A valid target template name couldn't be found");
+
                 if (applyPatchResult.GetProcessing() != AZ::JsonSerializationResult::Processing::Completed)
                 {
                     AZ_Error(
@@ -190,6 +195,14 @@ namespace AzToolsFramework
                         m_sourceTemplateId, m_targetTemplateId);
                     return false;
                 }
+                if (applyPatchResult.GetOutcome() == AZ::JsonSerializationResult::Outcomes::PartialSkip)
+                {
+                    AZ_Error(
+                        "Prefab", false,
+                        "Link::UpdateTarget - Some of the patches couldn't be applied on the source template '%s' present under the  "
+                        "target Template '%s'.",
+                        sourceTemplateName->get().GetString(), targetTemplateName->get().GetString());
+                }
             }
 
             // This is a guardrail to ensure the linked instance dom always has the LinkId value

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabDomUtils.cpp

@@ -236,6 +236,26 @@ namespace AzToolsFramework
                 return findInstancesResult->get();
             }
 
+            AZ::JsonSerializationResult::ResultCode ApplyPatches(
+                PrefabDomValue& prefabDomToApplyPatchesOn, PrefabDom::AllocatorType& allocator, const PrefabDomValue& patches)
+            {
+                auto issueReportingCallback = [](AZStd::string_view, AZ::JsonSerializationResult::ResultCode result,
+                                                 AZStd::string_view) -> AZ::JsonSerializationResult::ResultCode
+                {
+                    using namespace AZ::JsonSerializationResult;
+                    if (result.GetProcessing() == Processing::Halted)
+                    {
+                        return ResultCode(result.GetTask(), Outcomes::PartialSkip);
+                    }
+                    return result;
+                };
+
+                AZ::JsonApplyPatchSettings applyPatchSettings;
+                applyPatchSettings.m_reporting = AZStd::move(issueReportingCallback);
+                return AZ::JsonSerialization::ApplyPatch(
+                    prefabDomToApplyPatchesOn, allocator, patches, AZ::JsonMergeApproach::JsonPatch, applyPatchSettings);
+            }
+
             void PrintPrefabDomValue(
                 [[maybe_unused]] const AZStd::string_view printMessage,
                 [[maybe_unused]] const PrefabDomValue& prefabDomValue)

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabDomUtils.h

@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <AzCore/Serialization/Json/JsonSerializationResult.h>
 #include <AzCore/std/optional.h>
 #include <AzCore/Asset/AssetCommon.h>
 #include <AzToolsFramework/Prefab/Instance/Instance.h>
@@ -122,6 +123,11 @@ namespace AzToolsFramework
              */
             PrefabDomValueConstReference GetInstancesValue(const PrefabDomValue& prefabDom);
 
+            AZ::JsonSerializationResult::ResultCode ApplyPatches(
+                PrefabDomValue& prefabDomToApplyPatchesOn,
+                PrefabDom::AllocatorType& allocator,
+                const PrefabDomValue& patches);
+
             /**
              * Prints the contents of the given prefab DOM value to the debug output console in a readable format.
              * @param printMessage The message that will be printed before printing the PrefabDomValue

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabUndo.cpp

@@ -261,8 +261,13 @@ namespace AzToolsFramework
             instanceDom.CopyFrom(instanceDomRef->get(), instanceDom.GetAllocator());
 
             //apply the patch to the template within the target
-            AZ::JsonSerializationResult::ResultCode result = AZ::JsonSerialization::ApplyPatch(instanceDom,
-                instanceDom.GetAllocator(), patch, AZ::JsonMergeApproach::JsonPatch);
+            AZ::JsonSerializationResult::ResultCode result = PrefabDomUtils::ApplyPatches(instanceDom, instanceDom.GetAllocator(), patch);
+
+            AZ_Error(
+                "Prefab",
+                result.GetOutcome() != AZ::JsonSerializationResult::Outcomes::PartialSkip &&
+                    result.GetOutcome() != AZ::JsonSerializationResult::Outcomes::Success,
+                "Some of the patches are not successfully applied.");
 
             //remove the link id placed into the instance
             auto linkIdIter = instanceDom.FindMember(PrefabDomUtils::LinkIdName);

Code/Framework/AzToolsFramework/Tests/Prefab/PrefabUndoLinkTests.cpp

@@ -96,8 +96,8 @@ namespace UnitTest
 
         //apply the patch
         PrefabDom& templateDomReference = m_prefabSystemComponent->FindTemplateDom(nestedTemplateId);
-        AZ::JsonSerializationResult::ResultCode result = AZ::JsonSerialization::ApplyPatch(templateDomReference,
-            templateDomReference.GetAllocator(), patch, AZ::JsonMergeApproach::JsonPatch);
+        AZ::JsonSerializationResult::ResultCode result =
+            PrefabDomUtils::ApplyPatches(templateDomReference, templateDomReference.GetAllocator(), patch);
 
         AZ_Error("Prefab", result.GetOutcome() == AZ::JsonSerializationResult::Outcomes::Success,
             "Patch was not successfully applied");