Add support for --enable-error-code and --disable-error-code (#9172)

Add ability to enable error codes globally from the command line
Add ability to disable error codes globally from the command line
Enabling error codes will always override disabling error codes
Update documentation to include new flags

Fixes #8975.

docs/source/command_line.rst

@@ -553,6 +553,36 @@ of the above sections.
     Note: the exact list of flags enabled by running :option:`--strict` may change
     over time.
 
+.. option:: --disable-error-code
+
+    This flag allows disabling one or multiple error codes globally.
+
+    .. code-block:: python
+
+        # no flag
+        x = 'a string'
+        x.trim()  # error: "str" has no attribute "trim"  [attr-defined]
+
+        # --disable-error-code attr-defined
+        x = 'a string'
+        x.trim()
+
+.. option:: --enable-error-code
+
+    This flag allows enabling one or multiple error codes globally.
+
+    Note: This flag will override disabled error codes from the --disable-error-code
+    flag
+
+    .. code-block:: python
+
+        # --disable-error-code attr-defined
+        x = 'a string'
+        x.trim()
+
+        # --disable-error-code attr-defined --enable-error-code attr-defined
+        x = 'a string'
+        x.trim()  # error: "str" has no attribute "trim"  [attr-defined]
 
 .. _configuring-error-messages:
 

mypy/build.py

@@ -223,7 +223,9 @@ def _build(sources: List[BuildSource],
                     options.show_error_codes,
                     options.pretty,
                     lambda path: read_py_file(path, cached_read, options.python_version),
-                    options.show_absolute_path)
+                    options.show_absolute_path,
+                    options.enabled_error_codes,
+                    options.disabled_error_codes)
     plugin, snapshot = load_plugins(options, errors, stdout, extra_plugins)
 
     # Add catch-all .gitignore to cache dir if we created it

mypy/errorcodes.py

@@ -3,19 +3,26 @@
 These can be used for filtering specific errors.
 """
 
-from typing import List
+from typing import Dict, List
 from typing_extensions import Final
 
 
 # All created error codes are implicitly stored in this list.
 all_error_codes = []  # type: List[ErrorCode]
 
+error_codes = {}  # type: Dict[str, ErrorCode]
+
 
 class ErrorCode:
-    def __init__(self, code: str, description: str, category: str) -> None:
+    def __init__(self, code: str,
+                 description: str,
+                 category: str,
+                 default_enabled: bool = True) -> None:
         self.code = code
         self.description = description
         self.category = category
+        self.default_enabled = default_enabled
+        error_codes[code] = self
 
     def __str__(self) -> str:
         return '<ErrorCode {}>'.format(self.code)

mypy/errors.py

@@ -164,14 +164,18 @@ def __init__(self,
                  show_error_codes: bool = False,
                  pretty: bool = False,
                  read_source: Optional[Callable[[str], Optional[List[str]]]] = None,
-                 show_absolute_path: bool = False) -> None:
+                 show_absolute_path: bool = False,
+                 enabled_error_codes: Optional[Set[ErrorCode]] = None,
+                 disabled_error_codes: Optional[Set[ErrorCode]] = None) -> None:
         self.show_error_context = show_error_context
         self.show_column_numbers = show_column_numbers
         self.show_error_codes = show_error_codes
         self.show_absolute_path = show_absolute_path
         self.pretty = pretty
         # We use fscache to read source code when showing snippets.
         self.read_source = read_source
+        self.enabled_error_codes = enabled_error_codes or set()
+        self.disabled_error_codes = disabled_error_codes or set()
         self.initialize()
 
     def initialize(self) -> None:
@@ -195,7 +199,9 @@ def copy(self) -> 'Errors':
                      self.show_error_codes,
                      self.pretty,
                      self.read_source,
-                     self.show_absolute_path)
+                     self.show_absolute_path,
+                     self.enabled_error_codes,
+                     self.disabled_error_codes)
         new.file = self.file
         new.import_ctx = self.import_ctx[:]
         new.function_or_member = self.function_or_member[:]
@@ -351,15 +357,25 @@ def add_error_info(self, info: ErrorInfo) -> None:
         self._add_error_info(file, info)
 
     def is_ignored_error(self, line: int, info: ErrorInfo, ignores: Dict[int, List[str]]) -> bool:
-        if line not in ignores:
+        if info.code and self.is_error_code_enabled(info.code) is False:
+            return True
+        elif line not in ignores:
             return False
         elif not ignores[line]:
             # Empty list means that we ignore all errors
             return True
-        elif info.code:
+        elif info.code and self.is_error_code_enabled(info.code) is True:
             return info.code.code in ignores[line]
         return False
 
+    def is_error_code_enabled(self, error_code: ErrorCode) -> bool:
+        if error_code in self.disabled_error_codes:
+            return False
+        elif error_code in self.enabled_error_codes:
+            return True
+        else:
+            return error_code.default_enabled
+
     def clear_errors_in_targets(self, path: str, targets: Set[str]) -> None:
         """Remove errors in specific fine-grained targets within a file."""
         if path in self.error_info_map:

mypy/main.py

@@ -18,6 +18,7 @@
 from mypy.find_sources import create_source_list, InvalidSourceList
 from mypy.fscache import FileSystemCache
 from mypy.errors import CompileError
+from mypy.errorcodes import error_codes
 from mypy.options import Options, BuildType
 from mypy.config_parser import parse_version, parse_config_file
 from mypy.split_namespace import SplitNamespace
@@ -612,6 +613,14 @@ def add_invertible_flag(flag: str,
         '--strict', action='store_true', dest='special-opts:strict',
         help=strict_help)
 
+    strictness_group.add_argument(
+        '--disable-error-code', metavar='NAME', action='append', default=[],
+        help="Disable a specific error code")
+    strictness_group.add_argument(
+        '--enable-error-code', metavar='NAME', action='append', default=[],
+        help="Enable a specific error code"
+    )
+
     error_group = parser.add_argument_group(
         title='Configuring error messages',
         description="Adjust the amount of detail shown in error messages.")
@@ -860,6 +869,23 @@ def set_strict_flags() -> None:
         parser.error("You can't make a variable always true and always false (%s)" %
                      ', '.join(sorted(overlap)))
 
+    # Process `--enable-error-code` and `--disable-error-code` flags
+    disabled_codes = set(options.disable_error_code)
+    enabled_codes = set(options.enable_error_code)
+
+    valid_error_codes = set(error_codes.keys())
+
+    invalid_codes = (enabled_codes | disabled_codes) - valid_error_codes
+    if invalid_codes:
+        parser.error("Invalid error code(s): %s" %
+                     ', '.join(sorted(invalid_codes)))
+
+    options.disabled_error_codes |= {error_codes[code] for code in disabled_codes}
+    options.enabled_error_codes |= {error_codes[code] for code in enabled_codes}
+
+    # Enabling an error code always overrides disabling
+    options.disabled_error_codes -= options.enabled_error_codes
+
     # Set build flags.
     if options.strict_optional_whitelist is not None:
         # TODO: Deprecate, then kill this flag

mypy/options.py

@@ -3,12 +3,15 @@
 import pprint
 import sys
 
-from typing_extensions import Final
+from typing_extensions import Final, TYPE_CHECKING
 from typing import Dict, List, Mapping, Optional, Pattern, Set, Tuple, Callable, Any
 
 from mypy import defaults
 from mypy.util import get_class_descriptors, replace_object_state
 
+if TYPE_CHECKING:
+    from mypy.errors import ErrorCode
+
 
 class BuildType:
     STANDARD = 0  # type: Final[int]
@@ -177,6 +180,14 @@ def __init__(self) -> None:
         # Variable names considered False
         self.always_false = []  # type: List[str]
 
+        # Error codes to disable
+        self.disable_error_code = []  # type: List[str]
+        self.disabled_error_codes = set()  # type: Set[ErrorCode]
+
+        # Error codes to enable
+        self.enable_error_code = []  # type: List[str]
+        self.enabled_error_codes = set()  # type: Set[ErrorCode]
+
         # Use script name instead of __main__
         self.scripts_are_modules = False
 

test-data/unit/check-flags.test

@@ -1530,3 +1530,48 @@ def f(a = None):
 no_implicit_optional = True
 \[mypy-m]
 no_implicit_optional = False
+
+[case testDisableErrorCode]
+# flags: --disable-error-code attr-defined
+x = 'should be fine'
+x.trim()
+
+[case testDisableDifferentErrorCode]
+# flags: --disable-error-code name-defined --show-error-code
+x = 'should not be fine'
+x.trim()  # E: "str" has no attribute "trim"  [attr-defined]
+
+[case testDisableMultipleErrorCode]
+# flags: --disable-error-code attr-defined --disable-error-code return-value --show-error-code
+x = 'should be fine'
+x.trim()
+
+def bad_return_type() -> str:
+    return None
+
+bad_return_type('no args taken!')  # E: Too many arguments for "bad_return_type"  [call-arg]
+
+[case testEnableErrorCode]
+# flags: --disable-error-code attr-defined --enable-error-code attr-defined --show-error-code
+x = 'should be fine'
+x.trim()  # E: "str" has no attribute "trim"  [attr-defined]
+
+[case testEnableDifferentErrorCode]
+# flags: --disable-error-code attr-defined --enable-error-code name-defined --show-error-code
+x = 'should not be fine'
+x.trim()  # E: "str" has no attribute "trim"  [attr-defined]
+
+[case testEnableMultipleErrorCode]
+# flags: \
+    --disable-error-code attr-defined \
+    --disable-error-code return-value \
+    --disable-error-code call-arg \
+    --enable-error-code attr-defined \
+    --enable-error-code return-value --show-error-code
+x = 'should be fine'
+x.trim()  # E: "str" has no attribute "trim"  [attr-defined]
+
+def bad_return_type() -> str:
+    return None  # E: Incompatible return value type (got "None", expected "str")  [return-value]
+
+bad_return_type('no args taken!')

test-data/unit/cmdline.test

@@ -1123,3 +1123,53 @@ import foo.bar
 [out]
 src/foo/bar.py: error: Source file found twice under different module names: 'src.foo.bar' and 'foo.bar'
 == Return code: 2
+
+[case testEnableInvalidErrorCode]
+# cmd: mypy --enable-error-code YOLO test.py
+[file test.py]
+x = 1
+[out]
+usage: mypy [-h] [-v] [-V] [more options; see below]
+            [-m MODULE] [-p PACKAGE] [-c PROGRAM_TEXT] [files ...]
+mypy: error: Invalid error code(s): YOLO
+== Return code: 2
+
+[case testDisableInvalidErrorCode]
+# cmd: mypy --disable-error-code YOLO test.py
+[file test.py]
+x = 1
+[out]
+usage: mypy [-h] [-v] [-V] [more options; see below]
+            [-m MODULE] [-p PACKAGE] [-c PROGRAM_TEXT] [files ...]
+mypy: error: Invalid error code(s): YOLO
+== Return code: 2
+
+[case testEnableAndDisableInvalidErrorCode]
+# cmd: mypy --disable-error-code YOLO --enable-error-code YOLO2 test.py
+[file test.py]
+x = 1
+[out]
+usage: mypy [-h] [-v] [-V] [more options; see below]
+            [-m MODULE] [-p PACKAGE] [-c PROGRAM_TEXT] [files ...]
+mypy: error: Invalid error code(s): YOLO, YOLO2
+== Return code: 2
+
+[case testEnableValidAndInvalidErrorCode]
+# cmd: mypy --enable-error-code attr-defined --enable-error-code YOLO test.py
+[file test.py]
+x = 1
+[out]
+usage: mypy [-h] [-v] [-V] [more options; see below]
+            [-m MODULE] [-p PACKAGE] [-c PROGRAM_TEXT] [files ...]
+mypy: error: Invalid error code(s): YOLO
+== Return code: 2
+
+[case testDisableValidAndInvalidErrorCode]
+# cmd: mypy --disable-error-code attr-defined --disable-error-code YOLO test.py
+[file test.py]
+x = 1
+[out]
+usage: mypy [-h] [-v] [-V] [more options; see below]
+            [-m MODULE] [-p PACKAGE] [-c PROGRAM_TEXT] [files ...]
+mypy: error: Invalid error code(s): YOLO
+== Return code: 2