oppia · aks681 · Apr 19, 2019 · Nov 26, 2018 · Nov 26, 2018 · Nov 27, 2018
diff --git a/scripts/pre_commit_linter.py b/scripts/pre_commit_linter.py
@@ -1249,6 +1249,76 @@ def _check_docstrings(all_files):
     return summary_messages
 
 
+def _check_args_order(all_files):
+    """If class args like self and cls are there
+    in function then it come first.
+    """
+    print 'Starting arguments order check'
+    print '----------------------------------------'
+    wrong_ordself_message = ('The first arg of the function should be self')
+    wrong_ordcls_message = ('The first arg of the function should be cls')
+    summary_messages = []
+    files_to_check = [
+        filename for filename in all_files if not
+        any(fnmatch.fnmatch(filename, pattern) for pattern in EXCLUDED_PATHS)
+        and filename.endswith('.py')]
+    failed = False
+    for filename in files_to_check:
+        with open(filename, 'r') as f:
+            file_content = f.readlines()
+            file_length = len(file_content)
+            for line_num in range(file_length):
+                line = file_content[line_num].lstrip().rstrip()
+                if line[0:3] == 'def ':
+                    START = '('
+                    END = ')'
+                    # Find index of '('.
+                    while 1:
+                        try:
+                            start_index = line.index(START)
+                            break
+                        except ValueError:
+                            line_num = line_num + 1
+                            line = file_content[line_num].lstrip().rstrip()
+                    # Find index of ')'.
+                    while 1:
+                        try:
+                            end_index = line.index(END)
+                            break
+                        except ValueError:
+                            line_num = line_num + 1
+                            line = file_content[line_num].lstrip().rstrip()
+                    if start_index + 1 != end_index:
+                        # Getting the list of all the arguments.
+                        args_list = line[start_index + 1:end_index].split(',')
+                        if 'self' in args_list:
+                            if args_list[0] != 'self':
+                                failed = True
+                                print '%s --> Line %s: %s' % (
+                                    filename, line_num + 1,
+                                    wrong_ordself_message)
+                            elif 'cls' in args_list:
+                                if args_list[0] != 'cls':
+                                    failed = True
+                                    print '%s --> Line %s: %s' % (
+                                        filename, line_num + 1,
+                                        wrong_ordcls_message)
+    print ''
+    print '----------------------------------------'
+    print ''
+    if failed:
+        summary_message = (
+            '%s   Arguments order check failed' % _MESSAGE_TYPE_FAILED)
+        print summary_message
+        summary_messages.append(summary_message)
+    else:
+        summary_message = (
+            '%s   Arguments order check passed' % _MESSAGE_TYPE_SUCCESS)
+        print summary_message
+        summary_messages.append(summary_message)
+    return summary_messages
+
+
 def _check_html_directive_name(all_files):
     """This function checks that all HTML directives end
     with _directive.html.
@@ -1743,6 +1813,7 @@ def main():
     import_order_messages = _check_import_order(all_files)
     newline_messages = _check_newline_character(all_files)
     docstring_messages = _check_docstrings(all_files)
+    args_order_messages = _check_args_order(all_files)
     comment_messages = _check_comments(all_files)
     # The html tags and attributes check has an additional
     # debug mode which when enabled prints the tag_stack for each file.
@@ -1754,9 +1825,10 @@ def main():
     all_messages = (
         directive_scope_messages + controller_dependency_messages +
         html_directive_name_messages + import_order_messages +
-        newline_messages + docstring_messages + comment_messages +
-        html_tag_and_attribute_messages + html_linter_messages +
-        linter_messages + pattern_messages + copyright_notice_messages)
+        newline_messages + docstring_messages + args_order_messages +
+        comment_messages + html_tag_and_attribute_messages +
+        html_linter_messages + linter_messages + pattern_messages +
+        copyright_notice_messages)
     if any([message.startswith(_MESSAGE_TYPE_FAILED) for message in
             all_messages]):
         sys.exit(1)