Add Option to extend the list of immutable calls (#204)

* add option to extend the list of immutable calls

* update README.rst about `extend-immutable-calls` option

Co-authored-by: Tobias Klare <[email protected]>
Co-authored-by: Cooper Lees <[email protected]>

README.rst

@@ -206,6 +206,14 @@ by default.  Those get enabled as soon as there is an ``ignore =`` line
 in your configuration.  I think this behavior is surprising so Bugbear's
 opinionated warnings require explicit selection.
 
+Configuration
+-------------
+
+The plugin currently has one setting:
+
+``extend-immutable-calls``: Specify a list of additional immutable calls.
+This could be useful, when using other libraries that provide more immutable calls,
+beside those already handled by ``flake8-bugbear``. Calls to these method will no longer raise a ``B008`` warning.
 
 Tests
 -----

bugbear.py

@@ -32,7 +32,17 @@ class BugBearChecker:
     def run(self):
         if not self.tree or not self.lines:
             self.load_file()
-        visitor = self.visitor(filename=self.filename, lines=self.lines)
+
+        if self.options and hasattr(self.options, "extend_immutable_calls"):
+            b008_extend_immutable_calls = set(self.options.extend_immutable_calls)
+        else:
+            b008_extend_immutable_calls = set()
+
+        visitor = self.visitor(
+            filename=self.filename,
+            lines=self.lines,
+            b008_extend_immutable_calls=b008_extend_immutable_calls,
+        )
         visitor.visit(self.tree)
         for e in itertools.chain(visitor.errors, self.gen_line_based_checks()):
             if self.should_warn(e.message[:4]):
@@ -73,6 +83,13 @@ def load_file(self):
     def add_options(optmanager):
         """Informs flake8 to ignore B9xx by default."""
         optmanager.extend_default_ignore(disabled_by_default)
+        optmanager.add_option(
+            "--extend-immutable-calls",
+            comma_separated_list=True,
+            parse_from_config=True,
+            default=[],
+            help="Skip B008 test for additional immutable calls.",
+        )
 
     @lru_cache()
     def should_warn(self, code):
@@ -146,6 +163,7 @@ def _typesafe_issubclass(cls, class_or_tuple):
 class BugBearVisitor(ast.NodeVisitor):
     filename = attr.ib()
     lines = attr.ib()
+    b008_extend_immutable_calls = attr.ib(default=attr.Factory(set))
     node_stack = attr.ib(default=attr.Factory(list))
     node_window = attr.ib(default=attr.Factory(list))
     errors = attr.ib(default=attr.Factory(list))
@@ -338,7 +356,10 @@ def check_for_b006(self, node):
                 call_path = ".".join(self.compose_call_path(default.func))
                 if call_path in B006.mutable_calls:
                     self.errors.append(B006(default.lineno, default.col_offset))
-                elif call_path not in B008.immutable_calls:
+                elif (
+                    call_path
+                    not in B008.immutable_calls | self.b008_extend_immutable_calls
+                ):
                     # Check if function call is actually a float infinity/NaN literal
                     if call_path == "float" and len(default.args) == 1:
                         float_arg = default.args[0]

tests/b008_extended.py

@@ -0,0 +1,16 @@
+from typing import List
+
+import fastapi
+from fastapi import Query
+
+
+def this_is_okay_extended(db=fastapi.Depends(get_db)):
+    ...
+
+
+def this_is_okay_extended_second(data: List[str] = fastapi.Query(None)):
+    ...
+
+
+def this_is_not_okay_relative_import_not_listed(data: List[str] = Query(None)):
+    ...

tests/test_bugbear.py

@@ -5,6 +5,7 @@
 import sys
 import unittest
 from pathlib import Path
+from unittest.mock import Mock
 
 from hypothesis import HealthCheck, given, settings
 from hypothesmith import from_grammar
@@ -125,6 +126,20 @@ def test_b007(self):
             ),
         )
 
+    def test_b008_extended(self):
+        filename = Path(__file__).absolute().parent / "b008_extended.py"
+
+        mock_options = Mock()
+        mock_options.extend_immutable_calls = ["fastapi.Depends", "fastapi.Query"]
+
+        bbc = BugBearChecker(filename=str(filename), options=mock_options)
+        errors = list(bbc.run())
+
+        self.assertEqual(
+            errors,
+            self.errors(B008(15, 66)),
+        )
+
     def test_b009_b010(self):
         filename = Path(__file__).absolute().parent / "b009_b010.py"
         bbc = BugBearChecker(filename=str(filename))