From b3ca68b7d9cc7a100a9ba4550c0de442146865f4 Mon Sep 17 00:00:00 2001
From: Lonami Exo <totufals@hotmail.com>
Date: Tue, 24 Oct 2017 10:07:31 +0200
Subject: [PATCH] Avoid cyclic imports caused by #348 (fix #357)

---
 telethon_generator/error_generator.py  |  3 +--
 telethon_generator/parser/tl_object.py |  3 +--
 telethon_generator/tl_generator.py     | 26 +++++++++++++++++++-------
 3 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/telethon_generator/error_generator.py b/telethon_generator/error_generator.py
index feb32b5a..30163dfc 100644
--- a/telethon_generator/error_generator.py
+++ b/telethon_generator/error_generator.py
@@ -154,11 +154,10 @@ def generate_code(output, json_file, errors_desc):
                 patterns.append((pattern, name))
                 capture = capture_names.get(name, 'x') if has_captures else None
                 # TODO Some errors have the same name but different code,
-                # split this accross different files?
+                # split this across different files?
                 write_error(f, error_code, name, description, capture)
 
         f.write('\n\nrpc_errors_all = {\n')
         for pattern, name in patterns:
             f.write('    {}: {},\n'.format(repr(pattern), name))
         f.write('}\n')
-
diff --git a/telethon_generator/parser/tl_object.py b/telethon_generator/parser/tl_object.py
index 79b4385d..278a66eb 100644
--- a/telethon_generator/parser/tl_object.py
+++ b/telethon_generator/parser/tl_object.py
@@ -104,8 +104,7 @@ class TLObject:
     def class_name_for(typename, is_function=False):
         """Gets the class name following the Python style guidelines"""
         # Courtesy of http://stackoverflow.com/a/31531797/4759433
-        result = re.sub(r'_([a-z])', lambda m: m.group(1).upper(),
-                typename)
+        result = re.sub(r'_([a-z])', lambda m: m.group(1).upper(), typename)
         result = result[:1].upper() + result[1:].replace('_', '')
         # If it's a function, let it end with "Request" to identify them
         if is_function:
diff --git a/telethon_generator/tl_generator.py b/telethon_generator/tl_generator.py
index f0a14fbc..b5d43656 100644
--- a/telethon_generator/tl_generator.py
+++ b/telethon_generator/tl_generator.py
@@ -129,11 +129,6 @@ class TLGenerator:
                 builder.writeln(
                     'from {}.tl.tlobject import TLObject'.format('.' * depth)
                 )
-                if ns:
-                    # Only import the parent types if we're not in such file
-                    builder.writeln(
-                            'from {}.tl import types'.format('.' * depth)
-                    )
 
                 # Add the relative imports to the namespaces,
                 # unless we already are in a namespace.
@@ -646,8 +641,25 @@ class TLGenerator:
             if not arg.skip_constructor_id:
                 builder.writeln('{} = reader.tgread_object()'.format(name))
             else:
-                builder.writeln('{} = types.{}.from_reader(reader)'.format(
-                        name, TLObject.class_name_for(arg.type)))
+                # Import the correct type inline to avoid cyclic imports.
+                # There may be better solutions so that we can just access
+                # all the types before the files have been parsed, but I
+                # don't know of any.
+                sep_index = arg.type.find('.')
+                if sep_index == -1:
+                    ns, t = '.', arg.type
+                else:
+                    ns, t = '.' + arg.type[:sep_index], arg.type[sep_index+1:]
+                class_name = TLObject.class_name_for(t)
+
+                # There would be no need to import the type if we're in the
+                # file with the same namespace, but since it does no harm
+                # and we don't have information about such thing in the
+                # method we just ignore that case.
+                builder.writeln('from {} import {}'.format(ns, class_name))
+                builder.writeln('{} = {}.from_reader(reader)'.format(
+                    name, class_name
+                ))
 
         # End vector and flag blocks if required (if we opened them before)
         if arg.is_vector: