Create UnsafeNonFatal for use in the fiber runtime

core/shared/src/main/scala/cats/effect/unsafe/UnsafeNonFatal.scala

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2020-2025 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cats.effect
+package unsafe
+
+import scala.util.control.ControlThrowable
+
+/**
+ * An alternative to [[scala.util.control.NonFatal]] that does not treat
+ * [[java.lang.InterruptedException]] as fatal. This is intended for the exclusive use of the
+ * Cats-Effect runtime. It is not recommended to treat interrupts as non-fatal in application
+ * code, as handling interrupts gracefully is the responsibility of the runtime, so
+ * [[UnsafeNonFatal]] should only be used in the fiber runtime.
+ */
+object UnsafeNonFatal {
+
+  /**
+   * Returns true if the provided `Throwable` is to be considered non-fatal, or false if it is
+   * to be considered fatal
+   */
+  def apply(t: Throwable): Boolean = t match {
+    case _: VirtualMachineError | _: ThreadDeath | _: LinkageError | _: ControlThrowable =>
+      false
+    case _ => true
+  }
+
+  /**
+   * Returns Some(t) if RuntimeNonFatal(t) == true, otherwise None
+   */
+  def unapply(t: Throwable): Option[Throwable] = Some(t).filter(apply)
+}