insert lines between packages

lib/python/pyflyby/_imports2s.py

@@ -1,6 +1,8 @@
 # pyflyby/_imports2s.py.
 # Copyright (C) 2011-2018 Karl Chen.
 # License: MIT http://opensource.org/licenses/MIT
+from collections import defaultdict
+
 import isort
 from   pyflyby._autoimp         import scan_for_import_issues
 from   pyflyby._file            import FileText, Filename
@@ -538,7 +540,33 @@ def sort_imports(codeblock):
     :param codeblock:
     :return: codeblock
     """
-    return isort.code(codeblock)
+    sorted_imports = isort.code(str(codeblock), force_sort_within_sections=True)
+    # Step 1: Split the input string into a list of lines
+    lines = sorted_imports.strip().split('\n')
+
+    # Step 2: Identify groups of imports and keep track of their line numbers
+    pkg_lines = defaultdict(list)
+    line_pkg_dict = {}
+    for i, line in enumerate(lines):
+        match = re.match(r'(from (\w+)|import (\w+))', line)
+        current_pkg = match.groups()[1:3]
+        current_pkg = current_pkg[0] if current_pkg[0] is not None else current_pkg[1]
+
+        pkg_lines[current_pkg].append(i)
+        line_pkg_dict[i] = current_pkg
+
+    # Step 3: Create the output list of lines with blank lines around groups with more than one import
+    output_lines = []
+    for i, line in enumerate(lines):
+        if i > 0 and line_pkg_dict[i] != line_pkg_dict[i-1] and len(pkg_lines[line_pkg_dict[i]]) > 1:
+            output_lines.append('')
+        output_lines.append(line)
+        if i < len(lines) - 1 and line_pkg_dict[i] != line_pkg_dict[i+1] and len(pkg_lines[line_pkg_dict[i]]) > 1:
+            output_lines.append('')
+
+    # Step 4: Join the lines to create the output string
+    sorted_output_str = '\n'.join(output_lines)
+    return PythonBlock(sorted_output_str)
 
 
 def transform_imports(codeblock, transformations, params=None):