Fix handlers for 'with' syntax in Transaction object

src/runtime/python/pypgf.c

@@ -330,6 +330,8 @@ static PyGetSetDef PGF_getseters[] = {
 };
 
 static PyMemberDef PGF_members[] = {
+    // {"revision", T_PYSSIZET, offsetof(PGFObject, revision), READONLY,
+    //  "the revision number of this PGF"},
     {NULL}  /* Sentinel */
 };
 

src/runtime/python/tests/test_transactions.py

@@ -18,7 +18,9 @@ def gr2(gr1):
     return gr1
 
 @pytest.fixture(scope="module")
-def gr3(gr1):
+def gr3():
+    # TODO how to avoid reloading from file?
+    gr1 = readPGF("../haskell/tests/basic.pgf")
     with gr1.newTransaction("bar_branch") as t:
         t.createFunction("bar", ty, 0, prob),
         t.createCategory("R", [(BIND_TYPE_EXPLICIT, "x", ty)], prob)
@@ -62,8 +64,8 @@ def test_extended_function_prob(gr2):
 
 # gr3
 
-# def test_branched_functions(gr3):
-#     assert gr3.functions == ["bar", "c", "ind", "s", "z"]
-#
-# def test_branched_function_type(gr3):
-#     assert gr3.functionType("bar") == ty
+def test_branched_functions(gr3):
+    assert gr3.functions == ["bar", "c", "ind", "s", "z"]
+
+def test_branched_function_type(gr3):
+    assert gr3.functionType("bar") == ty

src/runtime/python/transactions.c

@@ -47,6 +47,7 @@ Transaction_commit(TransactionObject *self, PyObject *args)
         return NULL;
     }
 
+    pgf_free_revision(self->pgf->db, self->pgf->revision);
     self->pgf->revision = self->revision;
 
     Py_RETURN_TRUE;
@@ -156,10 +157,10 @@ Transaction_dropCategory(TransactionObject *self, PyObject *args)
     Py_RETURN_NONE;
 }
 
-static PyObject *
+static TransactionObject *
 Transaction_enter(TransactionObject *self, PyObject *Py_UNUSED(ignored))
 {
-    Py_RETURN_TRUE;
+    return self;
 }
 
 static PyObject *