From c386e08e1c5ce23212a1adc6f70cd394baf46130 Mon Sep 17 00:00:00 2001
From: Ashley Rogers <ashley.rogers@bentley.com>
Date: Mon, 27 Jan 2025 14:13:51 -0500
Subject: [PATCH 1/3] Check for null tileset in SampleHeightMostDetailed

---
 ...iumSampleHeightMostDetailedAsyncAction.cpp | 24 ++++++++++++-----
 .../Tests/SampleHeightMostDetailed.spec.cpp   | 27 ++++++++++++++++++-
 2 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/Source/CesiumRuntime/Private/CesiumSampleHeightMostDetailedAsyncAction.cpp b/Source/CesiumRuntime/Private/CesiumSampleHeightMostDetailedAsyncAction.cpp
index 24d06196f..5f1ad933f 100644
--- a/Source/CesiumRuntime/Private/CesiumSampleHeightMostDetailedAsyncAction.cpp
+++ b/Source/CesiumRuntime/Private/CesiumSampleHeightMostDetailedAsyncAction.cpp
@@ -16,13 +16,25 @@ UCesiumSampleHeightMostDetailedAsyncAction::SampleHeightMostDetailed(
 }
 
 void UCesiumSampleHeightMostDetailedAsyncAction::Activate() {
-  this->RegisterWithGameInstance(this->_pTileset);
+  if (!IsValid(this->_pTileset)) {
+    TArray<FString> Warnings;
+    Warnings.Push(TEXT(
+        "Invalid Tileset parameter passed to UCesiumSampleHeightMostDetailedAsyncAction, returning no results"));
 
-  this->_pTileset->SampleHeightMostDetailed(
-      this->_longitudeLatitudeHeightArray,
-      FCesiumSampleHeightMostDetailedCallback::CreateUObject(
-          this,
-          &UCesiumSampleHeightMostDetailedAsyncAction::RaiseOnHeightsSampled));
+    this->RaiseOnHeightsSampled(
+        this->_pTileset,
+        TArray<FCesiumSampleHeightResult>(),
+        Warnings);
+  } else {
+    this->RegisterWithGameInstance(this->_pTileset);
+
+    this->_pTileset->SampleHeightMostDetailed(
+        this->_longitudeLatitudeHeightArray,
+        FCesiumSampleHeightMostDetailedCallback::CreateUObject(
+            this,
+            &UCesiumSampleHeightMostDetailedAsyncAction::
+                RaiseOnHeightsSampled));
+  }
 }
 
 void UCesiumSampleHeightMostDetailedAsyncAction::RaiseOnHeightsSampled(
diff --git a/Source/CesiumRuntime/Private/Tests/SampleHeightMostDetailed.spec.cpp b/Source/CesiumRuntime/Private/Tests/SampleHeightMostDetailed.spec.cpp
index 479e63beb..ea454cd7e 100644
--- a/Source/CesiumRuntime/Private/Tests/SampleHeightMostDetailed.spec.cpp
+++ b/Source/CesiumRuntime/Private/Tests/SampleHeightMostDetailed.spec.cpp
@@ -309,7 +309,7 @@ void FSampleHeightMostDetailedSpec::Define() {
     });
 
     LatentIt(
-        "",
+        "invalid tileset URL",
         EAsyncExecution::TaskGraphMainThread,
         [this](const FDoneDelegate& done) {
           // Two slightly different error messages will occur, depending on
@@ -354,5 +354,30 @@ void FSampleHeightMostDetailedSpec::Define() {
                     done.ExecuteIfBound();
                   }));
         });
+
+    LatentIt(
+        "tileset parameter is nullptr",
+        EAsyncExecution::TaskGraphMainThread,
+        [this](const FDoneDelegate& done) {
+          UCesiumSampleHeightMostDetailedAsyncAction* pAsync =
+              UCesiumSampleHeightMostDetailedAsyncAction::
+                  SampleHeightMostDetailed(
+                      nullptr,
+                      {FVector(144.93406, -37.82457, 1.0)});
+
+          USampleHeightCallbackReceiver::Bind(
+              pAsync->OnHeightsSampled,
+              [this, done](
+                  const TArray<FCesiumSampleHeightResult>& result,
+                  const TArray<FString>& warnings) {
+                TestEqual("Number of results", result.Num(), 0);
+                TestEqual("Number of warnings", warnings.Num(), 1);
+                done.ExecuteIfBound();
+              });
+
+          pAsync->Activate();
+        });
   });
+
+
 }

From 9e3d291dfb011fe898f50ba313cfcfb52a1706f8 Mon Sep 17 00:00:00 2001
From: Ashley Rogers <ashley.rogers@bentley.com>
Date: Mon, 27 Jan 2025 14:14:37 -0500
Subject: [PATCH 2/3] Format

---
 .../Private/Tests/SampleHeightMostDetailed.spec.cpp             | 2 --
 1 file changed, 2 deletions(-)

diff --git a/Source/CesiumRuntime/Private/Tests/SampleHeightMostDetailed.spec.cpp b/Source/CesiumRuntime/Private/Tests/SampleHeightMostDetailed.spec.cpp
index ea454cd7e..a0ed673ac 100644
--- a/Source/CesiumRuntime/Private/Tests/SampleHeightMostDetailed.spec.cpp
+++ b/Source/CesiumRuntime/Private/Tests/SampleHeightMostDetailed.spec.cpp
@@ -378,6 +378,4 @@ void FSampleHeightMostDetailedSpec::Define() {
           pAsync->Activate();
         });
   });
-
-
 }

From 2abe952dea9ea5b390b7db020b6efb1556b4be6a Mon Sep 17 00:00:00 2001
From: Ashley Rogers <ashley.rogers@bentley.com>
Date: Mon, 27 Jan 2025 14:15:26 -0500
Subject: [PATCH 3/3] Update CHANGES

---
 CHANGES.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGES.md b/CHANGES.md
index 706a1577c..4e3636795 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -9,6 +9,7 @@
 ##### Fixes :wrench:
 
 - Fixed another bug in `CesiumSubLevelSwitcherComponent` that could prevent all sub-levels from loading if a single sub-level failed to load.
+- Fixed crash when calling `SampleHeightMostDetailed` blueprint function without a valid tileset.
 
 ### v2.12.0 - 2025-01-02