Returning only modified cloud function. Not all cloud function

[rickmak]

Current implementation is to grep the changed files with pattern. Which is okay to return all cloud function to in a files.

There will be problem to apply this searching method to the patch files.

Scenario.
patch with the following

+     with _get_engine().begin() as conn:
+        trans = conn.begin()
+            conn.execute(sa.text('''SQL'''))

The patch file can contain no skygear.op declaration. But it modify the op function.

To achieve the goal, we will need to do a context analysis to see which function is got modify and see if that function is skygear.op or not. Cannot just grep the diff.

To make it happen, we need to parse the source code. We take a look at parser for python and Esprima for js