Fix lines_before_imports appending lines after comments

isort/core.py

@@ -72,6 +72,7 @@ def process(
     stripped_line: str = ""
     end_of_file: bool = False
     verbose_output: List[str] = []
+    lines_before: List[str] = []
 
     if config.float_to_top:
         new_input = ""
@@ -333,6 +334,15 @@ def process(
                     not_imports = True
 
         if not_imports:
+
+            if not was_in_quote and config.lines_before_imports > -1:
+                if line.strip() == "":
+                    lines_before += line
+                    continue
+                if not import_section:
+                    output_stream.write("".join(lines_before))
+                lines_before = []
+
             raw_import_section: str = import_section
             if (
                 add_imports

tests/unit/test_isort.py

@@ -1716,14 +1716,28 @@ def test_order_by_type() -> None:
 
 def test_custom_lines_before_import_section() -> None:
     """Test the case where the number of lines to output after imports has been explicitly set."""
-    test_input = "from a import b\nfrom c import d\nfoo = 'bar'\n"
+    test_input = """from a import b
+
+foo = 'bar'
+"""
+
+    ln = "\n"
 
     # default case is no line added before the import
-    assert isort.code(test_input) == ("from a import b\nfrom c import d\n\nfoo = 'bar'\n")
+    assert isort.code(test_input) == (test_input)
 
     # test again with a custom number of lines before the import section
-    assert isort.code(test_input, lines_before_imports=2) == (
-        "\n\nfrom a import b\nfrom c import d\n\nfoo = 'bar'\n"
+    assert isort.code(test_input, lines_before_imports=2) == 2 * ln + test_input
+
+    comment = "# Comment\n"
+
+    # test with a comment above
+    assert isort.code(comment + ln + test_input, lines_before_imports=0) == comment + test_input
+
+    # test with comments with empty lines
+    assert (
+        isort.code(comment + ln + comment + 3 * ln + test_input, lines_before_imports=1)
+        == comment + ln + comment + 1 * ln + test_input
     )