From 575d62de1058aa93aa5726890c51a95d9929aa03 Mon Sep 17 00:00:00 2001
From: Jonas Maurus <jdelic@users.noreply.github.com>
Date: Fri, 5 Apr 2019 00:28:39 +0200
Subject: [PATCH 1/3] Fix generator support for Python 3. The wrapper should
 not yield itself.

---
 src/aspectlib/py3support.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/aspectlib/py3support.py b/src/aspectlib/py3support.py
index db9f907..864b5f8 100644
--- a/src/aspectlib/py3support.py
+++ b/src/aspectlib/py3support.py
@@ -36,7 +36,7 @@ def advising_generator_wrapper_py3(*args, **kwargs):
                         kwargs = advice.kwargs
                     gen = cutpoint_function(*args, **kwargs)
                     try:
-                        result = yield from gen
+                        result = next(gen)
                     except BaseException:
                         advice = advisor.throw(*sys.exc_info())
                     else:

From 8fe1359801c132d1aeda53696b53f4f04bc902a7 Mon Sep 17 00:00:00 2001
From: Jonas Maurus <jdelic@users.noreply.github.com>
Date: Fri, 5 Apr 2019 16:05:40 +0200
Subject: [PATCH 2/3] Rewrite advising_generator_wrapper_py3

This is what I perceive to be the correct behavior for advising generators, where the advisor generator gets instantiated once per iteration on the cutpoint generator function
---
 src/aspectlib/py3support.py | 59 ++++++++++++++++---------------------
 1 file changed, 26 insertions(+), 33 deletions(-)

diff --git a/src/aspectlib/py3support.py b/src/aspectlib/py3support.py
index 864b5f8..57d8538 100644
--- a/src/aspectlib/py3support.py
+++ b/src/aspectlib/py3support.py
@@ -20,38 +20,31 @@ def decorate_advising_generator_py3(advising_function, cutpoint_function, bind):
     assert isgeneratorfunction(cutpoint_function)
 
     def advising_generator_wrapper_py3(*args, **kwargs):
-        if bind:
-            advisor = advising_function(cutpoint_function, *args, **kwargs)
-        else:
-            advisor = advising_function(*args, **kwargs)
-        if not isgenerator(advisor):
-            raise ExpectedGenerator("advising_function %s did not return a generator." % advising_function)
-        try:
+        gen = cutpoint_function(*args, **kwargs)
+        while True:
+            if bind:
+                advisor = advising_function(cutpoint_function, *args, **kwargs)
+            else:
+                advisor = advising_function(*args, **kwargs)
+
+            if not isgenerator(advisor):
+                raise ExpectedGenerator("advising_function %s did not return a generator." % advising_function)
+
             advice = next(advisor)
-            while True:
-                logdebug('Got advice %r from %s', advice, advising_function)
-                if advice is Proceed or advice is None or isinstance(advice, Proceed):
-                    if isinstance(advice, Proceed):
-                        args = advice.args
-                        kwargs = advice.kwargs
-                    gen = cutpoint_function(*args, **kwargs)
-                    try:
-                        result = next(gen)
-                    except BaseException:
-                        advice = advisor.throw(*sys.exc_info())
-                    else:
-                        try:
-                            advice = advisor.send(result)
-                        except StopIteration:
-                            return result
-                    finally:
-                        gen.close()
-                elif advice is Return:
-                    return
-                elif isinstance(advice, Return):
-                    raise StopIteration(advice.value)
-                else:
-                    raise UnacceptableAdvice("Unknown advice %s" % advice)
-        finally:
-            advisor.close()
+            logdebug('Got advice %r from %s', advice, advising_function)
+            if advice is Proceed or advice is None or isinstance(advice, Proceed):
+                try:
+                    result = next(gen)
+                    advice = advisor.send(result)
+                except StopIteration as e:
+                    return e.value
+                except BaseException:
+                    advice = advisor.throw(*sys.exc_info())
+
+            if advice is Return:
+                yield
+            elif isinstance(advice, Return):
+                yield advice.value
+            else:
+                raise UnacceptableAdvice("Unknown advice %s" % advice)
     return mimic(advising_generator_wrapper_py3, cutpoint_function)

From 262c391ec892e335c4a95c470d1e3a805cdbcde7 Mon Sep 17 00:00:00 2001
From: Jonas Maurus <jdelic@users.noreply.github.com>
Date: Sun, 7 Apr 2019 13:57:52 +0200
Subject: [PATCH 3/3] In this design Return without value should yield the last
 result

---
 src/aspectlib/py3support.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/aspectlib/py3support.py b/src/aspectlib/py3support.py
index 57d8538..3a0d09f 100644
--- a/src/aspectlib/py3support.py
+++ b/src/aspectlib/py3support.py
@@ -32,6 +32,7 @@ def advising_generator_wrapper_py3(*args, **kwargs):
 
             advice = next(advisor)
             logdebug('Got advice %r from %s', advice, advising_function)
+            result = None
             if advice is Proceed or advice is None or isinstance(advice, Proceed):
                 try:
                     result = next(gen)
@@ -42,7 +43,7 @@ def advising_generator_wrapper_py3(*args, **kwargs):
                     advice = advisor.throw(*sys.exc_info())
 
             if advice is Return:
-                yield
+                yield result
             elif isinstance(advice, Return):
                 yield advice.value
             else: