Merge pull request #1490 from PyCQA/issue/1488/isort-mangling-lines-that-start-with-from

Issue/1488/isort mangling lines that start with from

4 files changed, 166 insertions, 2 deletions

diff --git a/.cruft.json b/.cruft.json
index f70213bc..dcbd6c8e 100644
--- a/.cruft.json
+++ b/.cruft.json
@@ -1,6 +1,6 @@
 {
     "template": "https://github.com/timothycrosley/cookiecutter-python/",
-    "commit": "4fe165a760a98a06d3fbef89aae3149767e489f3",
+    "commit": "ff6836bfaa247c65ff50b39c520ed12d91bf5a20",
     "context": {
         "cookiecutter": {
             "full_name": "Timothy Crosley",
@@ -13,4 +13,4 @@
         }
     },
     "directory": ""
-}
+}
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f6a0ce5a..1d8a50bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,9 @@ Changelog
 NOTE: isort follows the [semver](https://semver.org/) versioning standard.
 Find out more about isort's release policy [here](https://pycqa.github.io/isort/docs/major_releases/release_policy/).
 
+### 5.5.3 [Hotfix] September 20, 2020
+  - Fixed #1488: in rare cases isort can mangle `yield from` or `raise from` statements.
+
 ### 5.5.2 [Hotfix] September 9, 2020
   - Fixed #1469: --diff option is ignored when input is from stdin.
 
diff --git a/isort/core.py b/isort/core.py
index f3197b99..d1e945d4 100644
--- a/isort/core.py
+++ b/isort/core.py
@@ -306,6 +306,7 @@ def process(
                     raw_import_section += line
                 if not contains_imports:
                     output_stream.write(import_section)
+
                 else:
                     leading_whitespace = import_section[: -len(import_section.lstrip())]
                     trailing_whitespace = import_section[len(import_section.rstrip()) :]
@@ -361,6 +362,34 @@ def process(
                 output_stream.write(line)
                 not_imports = False
 
+            if stripped_line and not in_quote and not import_section and not next_import_section:
+                if stripped_line == "yield":
+                    while not stripped_line or stripped_line == "yield":
+                        new_line = input_stream.readline()
+                        if not new_line:
+                            break
+
+                        output_stream.write(new_line)
+                        stripped_line = new_line.strip().split("#")[0]
+
+                if stripped_line.startswith("raise") or stripped_line.startswith("yield"):
+                    if "(" in stripped_line:
+                        while ")" not in stripped_line:
+                            new_line = input_stream.readline()
+                            if not new_line:
+                                break
+
+                            output_stream.write(new_line)
+                            stripped_line = new_line.strip().split("#")[0]
+
+                    while stripped_line.endswith("\\"):
+                        new_line = input_stream.readline()
+                        if not new_line:
+                            break
+
+                        output_stream.write(new_line)
+                        stripped_line = new_line.strip().split("#")[0]
+
     return made_changes
 
 
diff --git a/tests/unit/test_regressions.py b/tests/unit/test_regressions.py
index 752adc34..4869d444 100644
--- a/tests/unit/test_regressions.py
+++ b/tests/unit/test_regressions.py
@@ -949,3 +949,135 @@ except ImportError as e:
         import_heading_thirdparty="related third party imports",
         show_diff=True,
     )
+
+
+def test_isort_should_leave_non_import_from_lines_alone_issue_1488():
+    """isort should never mangle non-import from statements.
+    See: https://github.com/PyCQA/isort/issues/1488
+    """
+    raise_from_should_be_ignored = """
+raise SomeException("Blah") \\
+    from exceptionsInfo.popitem()[1]
+"""
+    assert isort.check_code(raise_from_should_be_ignored, show_diff=True)
+
+    yield_from_should_be_ignored = """
+def generator_function():
+    yield \\
+        from other_function()[1]
+"""
+    assert isort.check_code(yield_from_should_be_ignored, show_diff=True)
+
+    wont_ignore_comment_contiuation = """
+# one
+
+# two
+
+
+def function():
+    # three \\
+    import b
+    import a
+"""
+    assert (
+        isort.code(wont_ignore_comment_contiuation)
+        == """
+# one
+
+# two
+
+
+def function():
+    # three \\
+    import a
+    import b
+"""
+    )
+
+    will_ignore_if_non_comment_continuation = """
+# one
+
+# two
+
+
+def function():
+    raise \\
+    import b
+    import a
+"""
+    assert isort.check_code(will_ignore_if_non_comment_continuation, show_diff=True)
+
+    yield_from_parens_should_be_ignored = """
+def generator_function():
+    (
+     yield
+     from other_function()[1]
+    )
+"""
+    assert isort.check_code(yield_from_parens_should_be_ignored, show_diff=True)
+
+    yield_from_lots_of_parens_and_space_should_be_ignored = """
+def generator_function():
+    (
+    (
+    ((((
+    (((((
+    ((
+    (((
+     yield
+
+
+
+     from other_function()[1]
+    )))))))))))))
+    )))
+"""
+    assert isort.check_code(yield_from_lots_of_parens_and_space_should_be_ignored, show_diff=True)
+
+    yield_from_should_be_ignored_when_following_import_statement = """
+def generator_function():
+    import os
+
+    yield \\
+    from other_function()[1]
+"""
+    assert isort.check_code(
+        yield_from_should_be_ignored_when_following_import_statement, show_diff=True
+    )
+
+    yield_at_file_end_ignored = """
+def generator_function():
+    (
+    (
+    ((((
+    (((((
+    ((
+    (((
+     yield
+"""
+    assert isort.check_code(yield_at_file_end_ignored, show_diff=True)
+
+    raise_at_file_end_ignored = """
+def generator_function():
+    (
+    (
+    ((((
+    (((((
+    ((
+    (((
+     raise (
+"""
+    assert isort.check_code(raise_at_file_end_ignored, show_diff=True)
+
+    raise_from_at_file_end_ignored = """
+def generator_function():
+    (
+    (
+    ((((
+    (((((
+    ((
+    (((
+     raise \\
+     from \\
+"""
+    assert isort.check_code(raise_from_at_file_end_ignored, show_diff=True)