Filter to avoid manually selecting packages/distributions multiple times

Signed-off-by: Xiaochao Dong (@damnever) <[email protected]>

Author: damnever

Diff for: pigar/core.py

@@ -10,7 +10,7 @@
 import importlib
 import importlib.util
 import importlib.machinery
-from typing import NamedTuple, List, Dict, Any, Optional, Tuple
+from typing import NamedTuple, List, Dict, Any, Optional, Tuple, Set, AnyStr
 import asyncio
 
 from .db import database
@@ -168,8 +168,12 @@ def analyze_requirements(
         importables = dict()
         tryimports = set()
         importlib.invalidate_caches()
+        visited_import_names = set()
 
-        def _resolve(module: Module, from_annotation: bool):
+        def _resolve(
+            module: Module, from_annotation: bool,
+            visited_import_names: Set[AnyStr]
+        ):
             name = module.name
             if is_user_module(module, self._project_root):
                 logger.debug(
@@ -199,6 +203,10 @@ def _resolve(module: Module, from_annotation: bool):
                 names.append(name)
 
             for name in names:
+                if name in visited_import_names:
+                    continue
+                visited_import_names.add(name)
+
                 if name in self._installed_dists_by_imports:
                     reqs = self._installed_dists_by_imports[name]
                     locs = _Locations.build_from(module.file, module.lineno)
@@ -218,7 +226,7 @@ def _resolve(module: Module, from_annotation: bool):
                                                            ] = from_annotation
 
         for module in imported_modules:
-            _resolve(module, False)
+            _resolve(module, False, visited_import_names)
         for annotation in annotations:
             if annotation.top_level_import_name is not None:
                 module = Module(
@@ -227,7 +235,7 @@ def _resolve(module: Module, from_annotation: bool):
                     lineno=annotation.lineno,
                     try_=False
                 )
-                _resolve(module, True)
+                _resolve(module, True, visited_import_names)
             elif annotation.distribution_name is not None:
                 req = self._installed_dists.get(
                     canonicalize_name(annotation.distribution_name), None
@@ -394,15 +402,15 @@ def write_requirements(
 
         if self._uncertain_requirements:
             stream.write(
-                '\nWARNING(pigar): some manual fixes are required since pigar has found duplicate requirements for the same import name.\n'
+                '\n# WARNING(pigar): some manual fixes might be required as pigar has detected duplicate requirements for the same import name (possibly for different submodules).\n'
             )
             uncertain_requirements = sorted(
                 self._uncertain_requirements.items(),
                 key=lambda item: item[0].lower()
             )
             for import_name, reqs in uncertain_requirements:
                 stream.write(
-                    f'# WARNING(pigar): the following duplicate requirements are for import name: {import_name}\n'
+                    f'# WARNING(pigar): the following duplicate requirements are for the import name: {import_name}\n'
                 )
                 with_ref_comments_once = with_ref_comments
                 for _, req in reqs.sorted_items():