Fix diff parser: issue with opening brackets

parso/python/diff.py

@@ -608,13 +608,6 @@ class _NodesTree(object):
                 break
 
             if node.type == 'endmarker':
-                # We basically removed the endmarker, but we are not allowed to
-                # remove the newline at the end of the line, otherwise it's
-                # going to be missing.
-                newline_index = max(node.prefix.rfind('\n'), node.prefix.rfind('\r'))
-                if newline_index > -1:
-                    new_prefix = node.prefix[:newline_index + 1]
-                # Endmarkers just distort all the checks below. Remove them.
                 break
 
             if node.type == 'error_leaf' and node.token_type in ('DEDENT', 'ERROR_DEDENT'):
@@ -677,6 +670,16 @@ class _NodesTree(object):
                     new_nodes.pop()
 
         if new_nodes:
+            if not _ends_with_newline(new_nodes[-1].get_last_leaf()) and not had_valid_suite_last:
+                p = new_nodes[-1].get_next_leaf().prefix
+                # We are not allowed to remove the newline at the end of the
+                # line, otherwise it's going to be missing. This happens e.g.
+                # if a bracket is around before that moves newlines to
+                # prefixes.
+                newline_index = max(p.rfind('\n'), p.rfind('\r'))
+                if newline_index > -1:
+                    new_prefix = p[:newline_index + 1]
+
             if had_valid_suite_last:
                 last = new_nodes[-1]
                 if last.type == 'decorated':

test/test_diff_parser.py

@@ -1176,9 +1176,9 @@ def test_error_dedent_in_between(differ):
     differ.parse(code1, copies=1, parsers=2)
 
 
-def test_x(differ):
+def test_some_other_indentation_issues(differ):
     code1 = dedent('''\
-        class SocketIO:
+        class C:
             x
             def f():
                 ""
@@ -1198,5 +1198,19 @@ def test_x(differ):
         a
         ''')
     differ.initialize(code1)
-    differ.parse(code2, copies=ANY, parsers=ANY, expect_error_leaves=True)
+    differ.parse(code2, copies=2, parsers=1, expect_error_leaves=True)
-    differ.parse(code1, copies=ANY, parsers=ANY)
+    differ.parse(code1, copies=2, parsers=2)
+
+
+def test_open_bracket(differ):
+    code1 = dedent('''\
+        class C:
+            1
+            2 # ha
+        ''')
+    code2 = insert_line_into_code(code1, 2, '    [str\n')
+    code3 = insert_line_into_code(code2, 4, '    str\n')
+    differ.initialize(code1)
+    differ.parse(code2, copies=1, parsers=1, expect_error_leaves=True)
+    differ.parse(code3, copies=1, parsers=1, expect_error_leaves=True)
+    differ.parse(code1, copies=1, parsers=1)