Added a fix for normalizing imports from more than one level of parent modules (issue/2152)

Author: bp72

isort/identify.py

@@ -5,7 +5,7 @@
 from pathlib import Path
 from typing import Iterator, NamedTuple, Optional, TextIO, Tuple
 
-from isort.parse import _normalize_line, _strip_syntax, skip_line
+from isort.parse import _strip_syntax, normalize_line, skip_line
 
 from .comments import parse as parse_comments
 from .settings import DEFAULT_CONFIG, Config
@@ -84,7 +84,7 @@ def imports(
             statements[-1] = f"{statements[-1]}#{end_of_line_comment[0]}"
 
         for statement in statements:
-            line, _raw_line = _normalize_line(statement)
+            line, _raw_line = normalize_line(statement)
             if line.startswith(("import ", "cimport ")):
                 type_of_import = "straight"
             elif line.startswith("from "):

isort/parse.py

@@ -1,4 +1,5 @@
 """Defines parsing functions used by isort for parsing import definitions"""
+import re
 from collections import OrderedDict, defaultdict
 from functools import partial
 from itertools import chain
@@ -36,18 +37,18 @@ def _infer_line_separator(contents: str) -> str:
     return "\n"
 
 
-def _normalize_line(raw_line: str) -> Tuple[str, str]:
+def normalize_line(raw_line: str) -> Tuple[str, str]:
     """Normalizes import related statements in the provided line.
 
     Returns (normalized_line: str, raw_line: str)
     """
-    line = raw_line.replace("from.import ", "from . import ")
-    line = line.replace("from.cimport ", "from . cimport ")
+    line = re.sub(r"from(\.+)cimport ", r"from \g<1> cimport ", raw_line)
+    line = re.sub(r"from(\.+)import ", r"from \g<1> import ", line)
     line = line.replace("import*", "import *")
-    line = line.replace(" .import ", " . import ")
-    line = line.replace(" .cimport ", " . cimport ")
+    line = re.sub(r" (\.+)import ", r" \g<1> import ", line)
+    line = re.sub(r" (\.+)cimport ", r" \g<1> cimport ", line)
     line = line.replace("\t", " ")
-    return (line, raw_line)
+    return line, raw_line
 
 
 def import_type(line: str, config: Config = DEFAULT_CONFIG) -> Optional[str]:
@@ -263,7 +264,7 @@ def file_contents(contents: str, config: Config = DEFAULT_CONFIG) -> ParsedConte
             statements[-1] = f"{statements[-1]}#{end_of_line_comment[0]}"
 
         for statement in statements:
-            line, raw_line = _normalize_line(statement)
+            line, raw_line = normalize_line(statement)
             type_of_import = import_type(line, config) or ""
             raw_lines = [raw_line]
             if not type_of_import:

tests/unit/test_parse.py

@@ -1,3 +1,4 @@
+import pytest
 from hypothesis import given
 from hypothesis import strategies as st
 
@@ -81,3 +82,29 @@ def test_fuzz_skip_line(line, in_quote, index, section_comments, needs_import):
         section_comments=section_comments,
         needs_import=needs_import,
     )
+
+
+@pytest.mark.parametrize(
+    "raw_line, expected",
+    (
+        ("from . cimport a", "from . cimport a"),
+        ("from.cimport a", "from . cimport a"),
+        ("from..cimport a", "from .. cimport a"),
+        ("from . import a", "from . import a"),
+        ("from.import a", "from . import a"),
+        ("from..import a", "from .. import a"),
+        ("import *", "import *"),
+        ("import*", "import *"),
+        ("from . import a", "from . import a"),
+        ("from .import a", "from . import a"),
+        ("from ..import a", "from .. import a"),
+        ("from . cimport a", "from . cimport a"),
+        ("from .cimport a", "from . cimport a"),
+        ("from ..cimport a", "from .. cimport a"),
+        ("from\t.\timport a", "from . import a"),
+    ),
+)
+def test_normalize_line(raw_line, expected):
+    line, returned_raw_line = parse.normalize_line(raw_line)
+    assert line == expected
+    assert returned_raw_line == raw_line