Add partial support for unused import removal

Author: albertas

README.md

@@ -173,6 +173,8 @@ code base is implemented in.
 - [ ] Check if file is still valid/parsable after automatic fixing, if not: halt the change and report error.
 
 ## Release notes
+- v2.3.1:
+    - Added support for automatic removal of imports.
 - v2.3.0:
     - Add `--dry` option.
     - Update error codes to use DCXX format instead of DCXXX.

deadcode/actions/remove_file_parts_from_content.py

@@ -34,6 +34,13 @@ def remove_as_from_end(line: str) -> str:
     return line
 
 
+def remove_comma_from_begining(line: str) -> str:
+    if not line.lstrip().startswith(','):
+        return line
+
+    return line.lstrip()[1:].lstrip()
+
+
 def remove_file_parts_from_content(content_lines: List[str], unused_file_parts: List[Part]) -> List[str]:
     """ """
     # How should move through the lines of content?
@@ -63,10 +70,14 @@ def remove_file_parts_from_content(content_lines: List[str], unused_file_parts:
             indentation_of_first_removed_line = get_indentation(line)
 
             if from_line == to_line:
+                # TODO: this check is a workaround for an assignment expression.
+                # Clean-ups have to be applied based on removable expression type.
                 if (line[:from_col] + line[to_col:]).strip().startswith('='):
                     line = line[:from_col]
                 else:
-                    line = remove_as_from_end(line[:from_col]) + line[to_col:]
+                    # TODO: should apply `as` removal rule only for particular expression type only
+                    # as well as comma removal.
+                    line = remove_as_from_end(line[:from_col]) + remove_comma_from_begining(line[to_col:])
 
                 unused_part_index += 1
 
@@ -87,6 +98,12 @@ def remove_file_parts_from_content(content_lines: List[str], unused_file_parts:
         # Is it last line, from the block, which have to be ignored?
         elif current_lineno == to_line:
             line = line[to_col:]
+
+            # Remove trailing comma, if we have removed something.
+            # TODO: this should be applied only for specific expression types only.
+            if line.lstrip().startswith(","):
+                line = line.lstrip()[1:].lstrip()
+
             unused_part_index += 1
             # TODO: Add tests for case, when comments are added at the start or end of the removed block
             if line.strip() and not line.startswith('#'):

deadcode/visitor/code_item.py

@@ -46,6 +46,7 @@ class CodeItem:  # TODO: This should also be a dataclass, because hash and tuple
         'type_',
         'filename',
         'code_parts',
+        'expression_code_parts',
         'scope',
         'inherits_from',
         'name_line',
@@ -66,6 +67,7 @@ def __init__(
         # first_column: int = 0,
         # last_column: Optional[int] = None,
         code_parts: Optional[List[Part]] = None,  # TODO: I should use a dataclass instead of a tuple for Part.
+        expression_code_parts: Optional[List[Part]] = None,
         scope: Optional[str] = None,
         inherits_from: Optional[List[str]] = None,
         name_line: Optional[int] = None,
@@ -85,6 +87,11 @@ def __init__(
         else:
             self.code_parts = code_parts
 
+        if expression_code_parts is None:
+            self.expression_code_parts = []
+        else:
+            self.expression_code_parts = expression_code_parts
+
         # if first_lineno is not None:
         #     pass
 

deadcode/visitor/dead_code_visitor.py

@@ -187,7 +187,8 @@ def _add_aliases(self, node: Union[ast.Import, ast.ImportFrom]) -> None:
             self._define(
                 self.defined_imports,
                 alias or name,
-                node,
+                first_node=name_and_alias,
+                expression_node=node,
                 ignore=_ignore_import,
             )
             if alias is not None:
@@ -234,6 +235,7 @@ def _define(
         name: str,
         first_node: ast.AST,
         last_node: Optional[ast.AST] = None,
+        expression_node: Optional[ast.AST] = None,
         message: str = '',
         ignore: Optional[Callable[[Path, str], bool]] = None,
     ) -> None:
@@ -255,8 +257,8 @@ def ignored(lineno: int, type_: UnusedCodeType) -> bool:
 
         last_node = last_node or first_node
         type_: UnusedCodeType = collection.type_  # type: ignore
-        first_lineno = lines.get_first_line_number(first_node)
 
+        first_lineno = lines.get_first_line_number(first_node)
         last_lineno = lines.get_last_line_number(last_node)
 
         inherits_from = getattr(first_node, 'inherits_from', None)
@@ -271,6 +273,20 @@ def ignored(lineno: int, type_: UnusedCodeType) -> bool:
             message=message,
             inherits_from=inherits_from,
         )
+
+        # TODO: Remaining import expressions has to be removed, when all imported
+        # names get removed. Pass whole import expression parts and evaluate if its still
+        # empty after making code adjustments.
+        # This feature is not yet implemented.
+        if expression_node:
+            expression_first_lineno = lines.get_first_line_number(expression_node)
+            expression_last_lineno = lines.get_last_line_number(expression_node)
+            code_item.expression_code_parts = [Part(
+                expression_first_lineno,
+                expression_last_lineno,
+                expression_node.col_offset,
+                expression_node.end_col_offset or 0)]
+
         self.scopes.add(code_item)
 
         if ignored(first_lineno, type_=type_):

tests/fix/test_unused_imports.py

@@ -0,0 +1,59 @@
+"""
+Test unused import detection and removal.
+"""
+
+from unittest import skip
+
+from deadcode.cli import main
+from deadcode.utils.base_test_case import BaseTestCase
+from deadcode.utils.fix_indent import fix_indent
+
+
+class TestAssignmentExpressionRemoval(BaseTestCase):
+    def test_variable(self):
+        self.files = {
+            'file2.py': """
+                from file1 import (
+                    foo,
+                    bar,
+                    xyz
+                )
+
+                from file1 import foo
+
+                def fn():
+                    pass
+
+                fn()
+                """
+        }
+
+        unused_names = main('file2.py --no-color --fix -v'.split())
+
+        self.assertEqual(
+            unused_names,
+            fix_indent("""\
+                file2.py:2:4: DC07 Import `foo` is never used
+                file2.py:3:4: DC07 Import `bar` is never used
+                file2.py:4:4: DC07 Import `xyz` is never used
+                file2.py:7:18: DC07 Import `foo` is never used
+
+                Removed 4 unused code items!""")
+        )
+
+        # TODO: empty imports statements should be removed as well.
+        self.assertFiles(
+            {
+                'file2.py': """
+                    from file1 import (
+                    )
+                    from file1 import 
+
+
+                    def fn():
+                        pass
+
+                    fn()
+                    """
+            }
+        )