Fix a number of exception-catching reference issues

Where we hadn't gone through and updated the exception-catch
sites to clear/hand off their owned ref appropriately.

src/capi/abstract.cpp

@@ -1911,6 +1911,7 @@ extern "C" PyObject* PyNumber_Divmod(PyObject* lhs, PyObject* rhs) noexcept {
     try {
         return binop(lhs, rhs, AST_TYPE::DivMod);
     } catch (ExcInfo e) {
+        e.clear();
         fatalOrError(PyExc_NotImplementedError, "unimplemented");
         return nullptr;
     }

src/capi/typeobject.cpp

@@ -967,6 +967,8 @@ Box* slotTpGetattrHookInternal(Box* self, BoxedString* name, GetattrRewriteArgs*
                         throw e;
                 }
 
+                e.clear();
+
                 if (grewrite_args.isSuccessful()) {
                     grewrite_args.getReturn(); // to make the asserts happy
                     grewrite_args.clearReturn();
@@ -1017,6 +1019,7 @@ Box* slotTpGetattrHookInternal(Box* self, BoxedString* name, GetattrRewriteArgs*
                     } else
                         throw e;
                 }
+                e.clear();
                 res = NULL;
             }
         }

src/codegen/pypa-parser.cpp

@@ -1006,6 +1006,10 @@ pypa::String pypaEscapeDecoder(const pypa::String& s, const pypa::String& encodi
     } catch (ExcInfo e) {
         error = true;
         BoxedString* error_message = str(e.value);
+
+        e.clear();
+        AUTO_DECREF(error_message);
+
         if (error_message && error_message->cls == str_cls)
             return std::string(error_message->s());
         return "Encountered an unknown error inside pypaEscapeDecoder";

src/codegen/unwinding.cpp

@@ -1021,8 +1021,9 @@ extern "C" void abort() {
         alarm(1);
         try {
             _printStacktrace();
-        } catch (ExcInfo) {
+        } catch (ExcInfo e) {
             fprintf(stderr, "error printing stack trace during abort()");
+            e.clear();
         }
 
         // Cancel the alarm.

src/jit.cpp

@@ -445,6 +445,7 @@ static int main(int argc, char** argv) noexcept {
                     throwCAPIException();
             } catch (ExcInfo e) {
                 e.printExcAndTraceback();
+                e.clear();
                 return 1;
             }
         }

src/runtime/builtin_modules/thread.cpp

@@ -76,6 +76,7 @@ static void* thread_start(Box* target, Box* varargs, Box* kwargs) {
         autoDecref(runtimeCall(target, ArgPassSpec(0, 0, true, kwargs != NULL), varargs, kwargs, NULL, NULL, NULL));
     } catch (ExcInfo e) {
         e.printExcAndTraceback();
+        e.clear();
     }
 
 #if STAT_TIMERS

src/runtime/capi.cpp

@@ -1664,7 +1664,8 @@ extern "C" BORROWED(struct _frame*) PyEval_GetFrame(void) noexcept {
     Box* frame = NULL;
     try {
         frame = getFrame(0);
-    } catch (ExcInfo) {
+    } catch (ExcInfo e) {
+        e.clear();
         RELEASE_ASSERT(0, "untested");
     }
     return (struct _frame*)frame;

src/runtime/classobj.cpp

@@ -673,6 +673,7 @@ Box* instanceNonzero(Box* _inst) {
     } catch (ExcInfo e) {
         if (!e.matches(AttributeError))
             throw e;
+        e.clear();
     }
 
     if (nonzero_func == NULL) {
@@ -682,6 +683,7 @@ Box* instanceNonzero(Box* _inst) {
         } catch (ExcInfo e) {
             if (!e.matches(AttributeError))
                 throw e;
+            e.clear();
         }
     }
 
@@ -745,6 +747,7 @@ Box* instanceGetslice(Box* _inst, Box* i, Box* j) {
     } catch (ExcInfo e) {
         if (!e.matches(AttributeError))
             throw e;
+        e.clear();
     }
 
     if (getslice_func == NULL) {
@@ -768,6 +771,7 @@ Box* instanceSetslice(Box* _inst, Box* i, Box* j, Box** sequence) {
     } catch (ExcInfo e) {
         if (!e.matches(AttributeError))
             throw e;
+        e.clear();
     }
 
     if (setslice_func == NULL) {
@@ -792,6 +796,7 @@ Box* instanceDelslice(Box* _inst, Box* i, Box* j) {
     } catch (ExcInfo e) {
         if (!e.matches(AttributeError))
             throw e;
+        e.clear();
     }
 
     if (delslice_func == NULL) {

src/runtime/generator.cpp

@@ -291,8 +291,10 @@ Box* generatorClose(Box* s) {
         autoDecref(generatorThrow(self, GeneratorExit, nullptr, nullptr));
         raiseExcHelper(RuntimeError, "generator ignored GeneratorExit");
     } catch (ExcInfo e) {
-        if (e.matches(StopIteration) || e.matches(GeneratorExit))
+        if (e.matches(StopIteration) || e.matches(GeneratorExit)) {
+            e.clear();
             return incref(None);
+        }
         throw e;
     }
     assert(0); // unreachable

src/runtime/set.cpp

@@ -718,6 +718,8 @@ Box* setContains(BoxedSet* self, Box* key) {
             if (!e.matches(TypeError))
                 throw e;
 
+            e.clear();
+
             BoxedSet* tmpKey = makeNewSet(frozenset_cls, key);
             AUTO_DECREF(tmpKey);
             return boxBool(self->s.find(tmpKey) != self->s.end());
@@ -742,6 +744,8 @@ Box* setRemove(BoxedSet* self, Box* key) {
             if (!e.matches(TypeError))
                 throw e;
 
+            e.clear();
+
             BoxedSet* tmpKey = makeNewSet(frozenset_cls, key);
             AUTO_DECREF(tmpKey);
             if (self->s.find(tmpKey) != self->s.end()) {
@@ -776,6 +780,8 @@ Box* setDiscard(BoxedSet* self, Box* key) {
             if (!e.matches(TypeError))
                 throw e;
 
+            e.clear();
+
             BoxedSet* tmpKey = makeNewSet(frozenset_cls, key);
             AUTO_DECREF(tmpKey);
             if (self->s.find(tmpKey) != self->s.end()) {

src/runtime/types.cpp

@@ -3011,7 +3011,8 @@ Box* objectRepr(Box* self) {
         mod = typeModule(type, NULL);
         if (!PyString_Check(mod))
             mod = NULL;
-    } catch (ExcInfo) {
+    } catch (ExcInfo e) {
+        e.clear();
     }
 
     DecrefHandle<Box> name(typeName(type, NULL));

test/tests/isinstance.py

-# expected: reffail
 class M(type):
     pass