Fix fstring issues when error leaves are involved

parso/python/diff.py

@@ -12,10 +12,9 @@ import logging
 
 from parso.utils import split_lines
 from parso.python.parser import Parser
-from parso.python.tree import EndMarker, PythonErrorLeaf
+from parso.python.tree import EndMarker
 from parso.python.tokenize import PythonToken
 from parso.python.token import PythonTokenTypes
-from parso.tree import search_ancestor
 
 LOG = logging.getLogger(__name__)
 DEBUG_DIFF_PARSER = False
@@ -432,9 +431,9 @@ class DiffParser(object):
         )
         stack = self._active_parser.stack
         self._replace_tos_indent = None
-        #print('start', line_offset + 1, indents)
+        # print('start', line_offset + 1, indents)
         for token in tokens:
-            #print(token, indents)
+            # print(token, indents)
             typ = token.type
             if typ == DEDENT:
                 if len(indents) < initial_indentation_count:

parso/python/tokenize.py

@@ -532,7 +532,7 @@ def tokenize_lines(lines, version_info, start_pos=(1, 0), indents=None, is_first
 
             if not pseudomatch:  # scan for tokens
                 match = whitespace.match(line, pos)
-                if pos == 0 and paren_level == 0:
+                if pos == 0 and paren_level == 0 and not fstring_stack:
                     for t in dedent_if_necessary(match.end()):
                         yield t
                 pos = match.end()

test/test_diff_parser.py

@@ -1609,3 +1609,24 @@ def test_backslash_insertion(differ):
     differ.initialize(code1)
     differ.parse(code2, parsers=2, copies=1, expect_error_leaves=True)
     differ.parse(code1, parsers=2, copies=1)
+
+
+def test_fstring_with_error_leaf(differ):
+    code1 = dedent("""\
+        def f():
+            x
+        def g():
+            y
+        """)
+    code2 = dedent("""\
+        def f():
+            x
+            F'''
+        def g():
+            y
+            {a
+        \x01
+        """)
+
+    differ.initialize(code1)
+    differ.parse(code2, parsers=1, copies=1, expect_error_leaves=True)