Fixed #1315: Extra newline before comment with -n + --fss.

CHANGELOG.md

@@ -3,12 +3,13 @@ Changelog
 
 NOTE: isort follows the [semver](https://semver.org/) versioning standard.
 
-### 5.1.0 July 12, 2020
+### 5.1.0 July TBD, 2020
   - isort now throws an exception if an invalid settings path is given (issue #1174).
   - Fixed #1178: support for semicolons in decorators.
+  - Fixed #1315: Extra newline before comment with -n + --fss.
 
 ### 5.0.9 July 11, 2020
-  - Fixed #1301: Import headings in nested sections leads to check errors
+is
 
 ### 5.0.8 July 11, 2020
   - Fixed #1277 & #1278: New line detection issues on Windows.

isort/output.py

@@ -132,7 +132,7 @@ def sorted_imports(
             for line in new_section_output:
                 comments = getattr(line, "comments", ())
                 if comments:
-                    if new_section_output and config.ensure_newline_before_comments:
+                    if section_output and config.ensure_newline_before_comments:
                         section_output.append("")
                     section_output.extend(comments)
                 section_output.append(str(line))

tests/test_regressions.py

@@ -289,3 +289,37 @@ def test_isort_shouldnt_fail_on_long_from_with_dot_issue_1190():
 )
 """
     )
+
+
+def test_isort_shouldnt_add_extra_new_line_when_fass_and_n_issue_1315():
+    """Test to ensure isort doesnt add a second extra new line when combining --fss and -n options.
+    See: https://github.com/timothycrosley/isort/issues/1315
+    """
+    assert isort.check_code(
+        """import sys
+
+# Comment canary
+from . import foo
+""",
+        ensure_newline_before_comments=True,  # -n
+        force_sort_within_sections=True,  # -fss
+        show_diff=True,  # for better debugging in the case the test case fails.
+    )
+
+    assert (
+        isort.code(
+            """
+from . import foo
+# Comment canary
+from .. import foo
+""",
+            ensure_newline_before_comments=True,
+            force_sort_within_sections=True,
+        )
+        == """
+from . import foo
+
+# Comment canary
+from .. import foo
+"""
+    )