Merge pull request #952 from CesiumGS/mutable-catch-lambda

Support for mutable lambdas in `catch` functions.

CHANGES.md

@@ -19,6 +19,7 @@
 - `GltfUtilities::intersectRayGltfModel` now reports a warning when given a model it can't compute the intersection with because it uses required extensions that are not supported.
 - Errors while loading raster overlays are now logged. Previously, they were silently ignored in many cases.
 - A raster overlay image failing to load will no longer completely prevent the geometry tile to which it is attached from rendering. Instead, once the raster overlay fails, the geometry tile will be shown without the raster overlay.
+- Fixed a bug in the various `catchImmediately` and `catchInMainThread` functions in `CesiumAsync` that prevented use of a mutable lambda.
 
 ### v0.39.0 - 2024-09-02
 

CesiumAsync/include/CesiumAsync/Impl/CatchFunction.h

@@ -22,7 +22,7 @@ struct CatchFunction {
     } catch (...) {
       // Make an exception_ptr task, then scheduler to a wrapper around f that
       // throws it, catches it, and calls f with a reference to it.
-      auto ptrToException = [f = std::move(f)](std::exception_ptr&& e) {
+      auto ptrToException = [f = std::move(f)](std::exception_ptr&& e) mutable {
         try {
           std::rethrow_exception(e);
         } catch (std::exception& e) {
@@ -52,7 +52,7 @@ struct CatchFunction<Func, void, Scheduler, TaskParameter> {
     } catch (...) {
       // Make an exception_ptr task, then scheduler to a wrapper around f that
       // throws it, catches it, and calls f with a reference to it.
-      auto ptrToException = [f = std::move(f)](std::exception_ptr&& e) {
+      auto ptrToException = [f = std::move(f)](std::exception_ptr&& e) mutable {
         try {
           std::rethrow_exception(e);
         } catch (std::exception& e) {

CesiumAsync/test/TestAsyncSystem.cpp

@@ -701,5 +701,23 @@ TEST_CASE("AsyncSystem") {
       CHECK_THROWS(future.waitInMainThread());
       CHECK(!called);
     }
+
+    SECTION(
+        "catchImmediately can return a value from a mutable lambda capture") {
+      auto promise = asyncSystem.createPromise<std::string>();
+      promise.reject(std::runtime_error("Some exception"));
+      std::string myValue = "value from catch";
+      Future<std::string> future =
+          promise.getFuture()
+              .catchImmediately([myValue = std::move(myValue)](
+                                    std::exception&& exception) mutable {
+                CHECK(std::string(exception.what()) == "Some exception");
+                return myValue;
+              })
+              .thenImmediately(
+                  [](std::string&& result) { return std::move(result); });
+      std::string result = future.waitInMainThread();
+      CHECK(result == "value from catch");
+    }
   }
 }