Add suppressed exceptions when one is thrown during releasing in use (#337)

Author: adamw

core/src/main/scala/ox/resource.scala

@@ -38,8 +38,20 @@ inline def use[R, T](inline acquire: R, inline release: R => Unit)(inline f: R =
   */
 inline def useInterruptible[R, T](inline acquire: R, inline release: R => Unit)(inline f: R => T): T =
   val r = acquire
+  var caught: Throwable = null
   try f(r)
-  finally release(r)
+  catch
+    case e: Throwable =>
+      caught = e
+      null.asInstanceOf[T]
+  finally
+    if caught == null then release(r)
+    else
+      try release(r)
+      catch case e: Throwable => caught.addSuppressed(e)
+      finally throw caught
+  end try
+end useInterruptible
 
 /** Use the given [[AutoCloseable]] resource, acquired using `acquire` in the given `f` code block. Releasing is [[uninterruptible]]. To use
   * multiple resources, consider creating a [[supervised]] scope and [[useCloseableInScope]] method.

core/src/test/scala/ox/ResourceTest.scala

@@ -143,4 +143,23 @@ class ResourceTest extends AnyFlatSpec with Matchers:
 
     trail.get shouldBe Vector("allocate", "in scope", "release")
   }
+
+  it should "add suppressed exception when there's an exception during releasing" in {
+    val trail = Trail()
+
+    class TestResource:
+      trail.add("allocate")
+      def release(): Unit =
+        trail.add("release")
+        throw new RuntimeException("e1")
+
+    try
+      use(new TestResource, _.release()) { r =>
+        trail.add("in scope")
+        throw new RuntimeException("e2")
+      }
+    catch case e => trail.add(s"exception ${e.getMessage} (${e.getSuppressed.map(_.getMessage).mkString(", ")})")
+
+    trail.get shouldBe Vector("allocate", "in scope", "release", "exception e2 (e1)")
+  }
 end ResourceTest