From f4ea799d42f8fc924fdaf5a58c0bef20471091ac Mon Sep 17 00:00:00 2001
From: "K. Lange" <klange@toaruos.org>
Date: Wed, 31 Mar 2021 19:06:33 +0900
Subject: [PATCH] Fix generator not being popped from stack on 'yield from'

---
 src/vm.c                               |  9 ++++-
 test/testYieldFromEventLoop.krk        | 47 ++++++++++++++++++++++++++
 test/testYieldFromEventLoop.krk.expect | 15 ++++++++
 3 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 test/testYieldFromEventLoop.krk
 create mode 100644 test/testYieldFromEventLoop.krk.expect

diff --git a/src/vm.c b/src/vm.c
index a6b403f..c7fdc53 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -2456,12 +2456,19 @@ _finishReturn: (void)0;
 					krk_push(krk_peek(0));
 					krk_push(krk_callSimple(krk_peek(0),0,0));
 				}
-				if (!krk_valuesSame(krk_peek(0), krk_peek(1))) break;
+				if (!krk_valuesSame(krk_peek(0), krk_peek(1))) {
+					/* Value to yield */
+					break;
+				}
+
+				krk_pop();
 
 				/* Does it have a final value? */
 				method = krk_valueGetAttribute_default(krk_peek(0), "__finish__", NONE_VAL());
 				if (!IS_NONE(method)) {
 					krk_push(method);
+					krk_swap(1);
+					krk_pop();
 					krk_push(krk_callSimple(krk_peek(0),0,0));
 				} else {
 					krk_pop();
diff --git a/test/testYieldFromEventLoop.krk b/test/testYieldFromEventLoop.krk
new file mode 100644
index 0000000..a76273f
--- /dev/null
+++ b/test/testYieldFromEventLoop.krk
@@ -0,0 +1,47 @@
+
+if not hasattr(__builtins__,'StopIteration'):
+    class StopIteration(Exception):
+        pass
+    __builtins__.StopIteration = StopIteration
+
+class Awaiter:
+    def __iter__(self):
+        yield "    Awaiter(): awaitable returns an iterator"
+        return "(all done)"
+
+def foo(i,result=None):
+    print('    foo(): hi')
+    result = yield from i()
+    print('      Awaiting result 1:', result)
+    result = yield from Awaiter()
+    print('      Awaiting result 2:', result)
+    result = yield from i()
+    print('      Awaiting result 3:', result)
+    print('    foo(): bi')
+    return "done"
+
+def bar():
+    print("    bar(): hello, there, I'm an async function")
+    return 42
+    yield 0xdeadbeef
+
+def run(coro, scheduled=None, next=None, result=None):
+    # Okay, let's see.
+    scheduled = [coro]
+    print("Starting run loop.")
+    while scheduled:
+        print("  Popping from scheduled list.")
+        next = scheduled.pop(0) # Yes, that's slow, I know.
+        try:
+            print("  Calling",type(next))
+            result = next.send(None)
+            if result == next:
+                raise StopIteration(result.__finish__())
+            print("  Returned with",result)
+            scheduled.append(next)
+        except StopIteration as e:
+            # Stop iteration value should be return value from foo()
+            print('Exception:', type(e), e)
+    print('Done with run loop.')
+
+run(foo(bar))
diff --git a/test/testYieldFromEventLoop.krk.expect b/test/testYieldFromEventLoop.krk.expect
new file mode 100644
index 0000000..25a55cf
--- /dev/null
+++ b/test/testYieldFromEventLoop.krk.expect
@@ -0,0 +1,15 @@
+Starting run loop.
+  Popping from scheduled list.
+  Calling <class 'generator'>
+    foo(): hi
+    bar(): hello, there, I'm an async function
+      Awaiting result 1: 42
+  Returned with     Awaiter(): awaitable returns an iterator
+  Popping from scheduled list.
+  Calling <class 'generator'>
+      Awaiting result 2: (all done)
+    bar(): hello, there, I'm an async function
+      Awaiting result 3: 42
+    foo(): bi
+Exception: <class '__main__.StopIteration'> done
+Done with run loop.