Add ability to enable/disable checks: (#41)

There is now a new "enabled" flag which can be used to skip the loading of a
check unless the user explictly opts into the check. By default, all checks
are enabled unless the author disables them.

I only added --enable, since adding --disable will require some additional
logic for parsing. Either way, --ignore does almost the same thing, but --disable
would prevent the check from even being loaded, whereas --ignore only suppresses
an error.

refurb/error.py

@@ -19,6 +19,7 @@ def __str__(self) -> str:
 
 @dataclass
 class Error:
+    enabled: ClassVar[bool] = True
     prefix: ClassVar[str] = "FURB"
     code: ClassVar[int]
     line: int

refurb/loader.py

@@ -13,6 +13,7 @@
 
 from . import checks as checks_module
 from .error import Error, ErrorCode
+from .settings import Settings
 
 Check = Callable[[Node, list[Error]], None]
 
@@ -40,15 +41,22 @@ def get_error_class(module: ModuleType) -> type[Error] | None:
     return None
 
 
-def load_checks(
-    ignore: set[ErrorCode], paths: list[str]
-) -> defaultdict[Type[Node], list[Check]]:
+def load_checks(settings: Settings) -> defaultdict[Type[Node], list[Check]]:
     found: defaultdict[Type[Node], list[Check]] = defaultdict(list)
+    ignore = settings.ignore or set()
+    paths = settings.load or []
+    enabled = settings.enable or set()
 
     for module in get_modules(paths):
         error = get_error_class(module)
+        if not error:
+            continue
+
+        error_code = ErrorCode.from_error(error)
+
+        is_enabled = error.enabled or error_code in enabled
 
-        if not error or ErrorCode.from_error(error) in ignore:
+        if not is_enabled or error_code in ignore:
             continue
 
         if func := getattr(module, "check", None):

refurb/main.py

@@ -103,7 +103,7 @@ def run_refurb(settings: Settings) -> Sequence[Error | str]:
             if settings.debug:
                 errors.append(str(tree))
 
-            checks = load_checks(settings.ignore or set(), settings.load or [])
+            checks = load_checks(settings)
             visitor = RefurbVisitor(checks)
 
             tree.accept(visitor)

refurb/settings.py

@@ -17,6 +17,7 @@ class Settings:
     explain: ErrorCode | None = None
     ignore: set[ErrorCode] | None = None
     load: list[str] | None = None
+    enable: set[ErrorCode] | None = None
     debug: bool = False
     generate: bool = False
     help: bool = False
@@ -45,8 +46,13 @@ def parse_config_file(contents: str) -> Settings:
                 parse_error_id(str(x)) for x in settings.get("ignore", [])
             )
 
+            enable = set(
+                parse_error_id(str(x)) for x in settings.get("enable", [])
+            )
+
             return Settings(
                 ignore=ignore or None,
+                enable=enable or None,
                 load=settings.get("load"),
                 quiet=settings.get("quiet", False),
             )
@@ -67,6 +73,7 @@ def parse_command_line_args(args: list[str]) -> Settings:
     iargs = iter(args)
     files: list[str] = []
     ignore: set[ErrorCode] = set()
+    enable: set[ErrorCode] = set()
     load: list[str] = []
     explain: ErrorCode | None = None
     debug = False
@@ -95,6 +102,14 @@ def parse_command_line_args(args: list[str]) -> Settings:
 
             ignore.add(parse_error_id(value))
 
+        elif arg == "--enable":
+            value = next(iargs, None)
+
+            if value is None:
+                raise ValueError(f'refurb: missing argument after "{arg}"')
+
+            enable.add(parse_error_id(value))
+
         elif arg == "--load":
             value = next(iargs, None)
 
@@ -112,6 +127,7 @@ def parse_command_line_args(args: list[str]) -> Settings:
     return Settings(
         files=files or None,
         ignore=ignore or None,
+        enable=enable or None,
         load=load or None,
         debug=debug,
         explain=explain,
@@ -123,6 +139,9 @@ def merge_settings(command_line: Settings, config_file: Settings) -> Settings:
     if not command_line.ignore:
         command_line.ignore = config_file.ignore
 
+    if not command_line.enable:
+        command_line.enable = config_file.enable
+
     if not command_line.load:
         command_line.load = config_file.load
 

test/custom_checks/disabled_check.py

@@ -0,0 +1,17 @@
+from dataclasses import dataclass
+
+from mypy.nodes import MypyFile
+
+from refurb.error import Error
+
+
+@dataclass
+class ErrorInfo(Error):
+    enabled = False
+    prefix = "XYZ"
+    code = 999
+    msg: str = "This message is disabled by default"
+
+
+def check(node: MypyFile, errors: list[Error]) -> None:
+    errors.append(ErrorInfo(node.line, node.column))

test/test_arg_parsing.py

@@ -64,6 +64,20 @@ def test_parse_ignore_check_missing_arg() -> None:
         parse_args(["--ignore"])
 
 
+def test_parse_enable() -> None:
+    got = parse_args(["--enable", "FURB123", "--enable", "321"])
+    expected = Settings(enable=set((ErrorCode(123), ErrorCode(321))))
+
+    assert got == expected
+
+
+def test_parse_enable_check_missing_arg() -> None:
+    with pytest.raises(
+        ValueError, match='refurb: missing argument after "--enable"'
+    ):
+        parse_args(["--enable"])
+
+
 def test_debug_parsing() -> None:
     assert parse_args(["--debug", "file"]) == Settings(
         files=["file"], debug=True
@@ -98,12 +112,15 @@ def test_parse_config_file() -> None:
 [tool.refurb]
 load = ["some", "folders"]
 ignore = [100, "FURB101"]
+enable = ["FURB111", "FURB222"]
 """
 
     config = parse_config_file(contents)
 
     assert config == Settings(
-        load=["some", "folders"], ignore=set((ErrorCode(100), ErrorCode(101)))
+        load=["some", "folders"],
+        ignore=set((ErrorCode(100), ErrorCode(101))),
+        enable=set((ErrorCode(111), ErrorCode(222))),
     )
 
 
@@ -131,14 +148,21 @@ def test_command_line_args_override_config_file() -> None:
 [tool.refurb]
 load = ["some", "folders"]
 ignore = [100, "FURB101"]
+enable = ["FURB111", "FURB222"]
 """
 
-    command_line_args = parse_args(["--load", "x", "--ignore", "123"])
+    command_line_args = parse_args(
+        ["--load", "x", "--ignore", "123", "--enable", "FURB200"]
+    )
     config_file = parse_config_file(contents)
 
     config = merge_settings(command_line_args, config_file)
 
-    assert config == Settings(load=["x"], ignore=set((ErrorCode(123),)))
+    assert config == Settings(
+        load=["x"],
+        ignore=set((ErrorCode(123),)),
+        enable=set((ErrorCode(200),)),
+    )
 
 
 def test_config_missing_ignore_option_is_allowed() -> None:

test/test_checks.py

@@ -69,3 +69,29 @@ def test_system_exit_is_caught() -> None:
     assert errors == [
         "refurb: There are no .py[i] files in directory 'test/e2e/empty_package'"
     ]
+
+
+DISABLED_CHECK = "test.custom_checks.disabled_check"
+
+
+def test_disabled_check_is_not_ran_by_default() -> None:
+    errors = run_refurb(
+        Settings(files=["test/e2e/dummy.py"], load=[DISABLED_CHECK])
+    )
+
+    assert not errors
+
+
+def test_disabled_check_ran_if_explicitly_enabled() -> None:
+    errors = run_refurb(
+        Settings(
+            files=["test/e2e/dummy.py"],
+            load=[DISABLED_CHECK],
+            enable=set((ErrorCode(prefix="XYZ", id=999),)),
+        )
+    )
+
+    expected = "test/e2e/dummy.py:1:1 [XYZ999]: This message is disabled by default"  # noqa: E501
+
+    assert len(errors) == 1
+    assert str(errors[0]) == expected