mypy.messages

module documentation

(source)

Facilities for generating error messages during type checking.

Don't add any non-trivial message construction logic to the type checker, as it can compromise clarity and make messages less consistent. Add such logic to this module instead. Literal messages, including those with format args, should be defined as constants in mypy.message_registry.

Historically we tried to avoid all message string literals in the type checker but we are moving away from this convention.

Class	`CollectAllInstancesQuery`	Undocumented
Class	`MessageBuilder`	Helper class for reporting type checker error messages with parameters.
Function	`append_invariance_notes`	Explain that the type is invariant and give notes for how to solve the issue.
Function	`best_matches`	Undocumented
Function	`callable_name`	Undocumented
Function	`capitalize`	Capitalize the first character of a string.
Function	`collect_all_instances`	Return all instances that `t` contains (including `t`).
Function	`extract_type`	If the argument is the name of a method (of form C.m), return the type portion in quotes (e.g. "y"). Otherwise, return the string unmodified.
Function	`find_defining_module`	Undocumented
Function	`find_type_overlaps`	Return a set of fullnames that share a short name and appear in either type.
Function	`for_function`	Undocumented
Function	`format_item_name_list`	Undocumented
Function	`format_key_list`	Undocumented
Function	`format_string_list`	Undocumented
Function	`format_type`	Convert a type to a relatively short string suitable for error messages.
Function	`format_type_bare`	Convert a type to a relatively short string suitable for error messages.
Function	`format_type_distinctly`	Jointly format types to distinct strings.
Function	`format_type_inner`	Convert a type to a relatively short string suitable for error messages.
Function	`get_bad_protocol_flags`	Return all incompatible attribute flags for members that are present in both 'left' and 'right'.
Function	`get_conflict_protocol_types`	Find members that are defined in 'left' but have incompatible types. Return them as a list of ('member', 'got', 'expected').
Function	`get_missing_protocol_members`	Find all protocol members of 'right' that are not implemented (i.e. completely missing) in 'left'.
Function	`make_inferred_type_note`	Explain that the user may have forgotten to type a variable.
Function	`plural_s`	Undocumented
Function	`pretty_callable`	Return a nice easily-readable representation of a callable type. For example: def [T <: int] f(self, x: int, y: T) -> None
Function	`pretty_class_or_static_decorator`	Return @classmethod or @staticmethod, if any, for the given callable type.
Function	`pretty_seq`	Undocumented
Function	`quote_type_string`	Quotes a type representation for use in messages.
Function	`strip_quotes`	Strip a double quote at the beginning and end of the string, if any.
Function	`variance_string`	Undocumented
Constant	`ARG_CONSTRUCTOR_NAMES`	Undocumented
Constant	`COMMON_MISTAKES`	Undocumented
Constant	`SUGGESTED_TEST_FIXTURES`	Undocumented
Constant	`TYPES_FOR_UNIMPORTED_HINTS`	Undocumented

def append_invariance_notes(notes, arg_type, expected_type): (source)

Explain that the type is invariant and give notes for how to solve the issue.

Parameters
notes:`List[str]`	Undocumented
arg_type:`Instance`	Undocumented
expected_type:`Instance`	Undocumented
Returns
`List[str]`	Undocumented

def best_matches(current, options): (source)

Undocumented

Parameters
current:`str`	Undocumented
options:`Iterable[str]`	Undocumented
Returns
`List[str]`	Undocumented

def callable_name(type): (source)

Undocumented

Parameters
type:`FunctionLike`	Undocumented
Returns
`Optional[str]`	Undocumented

def capitalize(s): (source)

Capitalize the first character of a string.

Parameters
s:`str`	Undocumented
Returns
`str`	Undocumented

def collect_all_instances(t): (source)

Return all instances that t contains (including t).

This is similar to collect_all_inner_types from typeanal but only returns instances and will recurse into fallbacks.

Parameters
t:`Type`	Undocumented
Returns
`List[Instance]`	Undocumented

def extract_type(name): (source)

If the argument is the name of a method (of form C.m), return the type portion in quotes (e.g. "y"). Otherwise, return the string unmodified.

Parameters
name:`str`	Undocumented
Returns
`str`	Undocumented

def find_defining_module(modules, typ): (source)

Undocumented

Parameters
modules:`Dict[str, MypyFile]`	Undocumented
typ:`CallableType`	Undocumented
Returns
`Optional[MypyFile]`	Undocumented

def find_type_overlaps(*types): (source)

Return a set of fullnames that share a short name and appear in either type.

This is used to ensure that distinct types with the same short name are printed with their fullname.

Parameters
*types:`Type`	Undocumented
Returns
`Set[str]`	Undocumented

def for_function(callee): (source)

Undocumented

Parameters
callee:`CallableType`	Undocumented
Returns
`str`	Undocumented

def format_item_name_list(s): (source)

Undocumented

Parameters
s:`Iterable[str]`	Undocumented
Returns
`str`	Undocumented

def format_key_list(keys, *, short=False): (source)

Undocumented

Parameters
keys:`List[str]`	Undocumented
short:`bool`	Undocumented
Returns
`str`	Undocumented

def format_string_list(lst): (source)

Undocumented

Parameters
lst:`List[str]`	Undocumented
Returns
`str`	Undocumented

def format_type(typ, verbosity=0): (source)

Convert a type to a relatively short string suitable for error messages.

verbosity is a coarse grained control on the verbosity of the type

This function returns a string appropriate for unmodified use in error messages; this means that it will be quoted in most cases. If modification of the formatted string is required, callers should use format_type_bare.

Parameters
typ:`Type`	Undocumented
verbosity:`int`	Undocumented
Returns
`str`	Undocumented

def format_type_bare(typ, verbosity=0, fullnames=None): (source)

Convert a type to a relatively short string suitable for error messages.

verbosity is a coarse grained control on the verbosity of the type fullnames specifies a set of names that should be printed in full

This function will return an unquoted string. If a caller doesn't need to perform post-processing on the string output, format_type should be used instead. (The caller may want to use quote_type_string after processing has happened, to maintain consistent quoting in messages.)

Parameters
typ:`Type`	Undocumented
verbosity:`int`	Undocumented
fullnames:`Optional[Set[str]]`	Undocumented
Returns
`str`	Undocumented

def format_type_distinctly(*types, bare=False): (source)

Jointly format types to distinct strings.

Increase the verbosity of the type strings until they become distinct while also requiring that distinct types with the same short name are formatted distinctly.

By default, the returned strings are created using format_type() and will be quoted accordingly. If bare is True, the returned strings will not be quoted; callers who need to do post-processing of the strings before quoting them (such as prepending * or **) should use this.

Parameters
*types:`Type`	Undocumented
bare:`bool`	Undocumented
Returns
`Tuple[str, ...]`	Undocumented

def format_type_inner(typ, verbosity, fullnames): (source)

Convert a type to a relatively short string suitable for error messages.

Args:: verbosity: a coarse grained control on the verbosity of the type fullnames: a set of names that should be printed in full

Parameters
typ:`Type`	Undocumented
verbosity:`int`	Undocumented
fullnames:`Optional[Set[str]]`	Undocumented
Returns
`str`	Undocumented

def get_bad_protocol_flags(left, right): (source)

Return all incompatible attribute flags for members that are present in both 'left' and 'right'.

Parameters
left:`Instance`	Undocumented
right:`Instance`	Undocumented
Returns
`List[Tuple[str, Set[int], Set[int]]]`	Undocumented

def get_conflict_protocol_types(left, right): (source)

Find members that are defined in 'left' but have incompatible types. Return them as a list of ('member', 'got', 'expected').

Parameters
left:`Instance`	Undocumented
right:`Instance`	Undocumented
Returns
`List[Tuple[str, Type, Type]]`	Undocumented

def get_missing_protocol_members(left, right): (source)

Find all protocol members of 'right' that are not implemented (i.e. completely missing) in 'left'.

Parameters
left:`Instance`	Undocumented
right:`Instance`	Undocumented
Returns
`List[str]`	Undocumented

def make_inferred_type_note(context, subtype, supertype, supertype_str): (source)

Explain that the user may have forgotten to type a variable.

The user does not expect an error if the inferred container type is the same as the return type of a function and the argument type(s) are a subtype of the argument type(s) of the return type. This note suggests that they add a type annotation with the return type instead of relying on the inferred type.

Parameters
context:`Context`	Undocumented
subtype:`Type`	Undocumented
supertype:`Type`	Undocumented
supertype_str:`str`	Undocumented
Returns
`str`	Undocumented

def plural_s(s): (source)

Undocumented

Parameters
s:`Union[int, Sequence[Any]]`	Undocumented
Returns
`str`	Undocumented

def pretty_callable(tp): (source)

Return a nice easily-readable representation of a callable type. For example:

def [T <: int] f(self, x: int, y: T) -> None

Parameters
tp:`CallableType`	Undocumented
Returns
`str`	Undocumented

def pretty_class_or_static_decorator(tp): (source)

Return @classmethod or @staticmethod, if any, for the given callable type.

Parameters
tp:`CallableType`	Undocumented
Returns
`Optional[str]`	Undocumented

def pretty_seq(args, conjunction): (source)

Undocumented

Parameters
args:`Sequence[str]`	Undocumented
conjunction:`str`	Undocumented
Returns
`str`	Undocumented

def quote_type_string(type_string): (source)

Quotes a type representation for use in messages.

Parameters
type_string:`str`	Undocumented
Returns
`str`	Undocumented

def strip_quotes(s): (source)

Strip a double quote at the beginning and end of the string, if any.

Parameters
s:`str`	Undocumented
Returns
`str`	Undocumented

def variance_string(variance): (source)

Undocumented

Parameters
variance:`int`	Undocumented
Returns
`str`	Undocumented

ARG_CONSTRUCTOR_NAMES = (source)

Undocumented

Value

{ARG_POS: 'Arg',
 ARG_OPT: 'DefaultArg',
 ARG_NAMED: 'NamedArg',
 ARG_NAMED_OPT: 'DefaultNamedArg',
 ARG_STAR: 'VarArg',
 ARG_STAR2: 'KwArg'}

COMMON_MISTAKES: Dict[str, Sequence[str]] = (source)

Undocumented

Value

{'add': ('append', 'extend')}

SUGGESTED_TEST_FIXTURES: dict[str, str] = (source)

Undocumented

Value

{'builtins.list': 'list.pyi',
 'builtins.dict': 'dict.pyi',
 'builtins.set': 'set.pyi',
 'builtins.tuple': 'tuple.pyi',
 'builtins.bool': 'bool.pyi',
 'builtins.Exception': 'exception.pyi',
 'builtins.BaseException': 'exception.pyi',
...

TYPES_FOR_UNIMPORTED_HINTS: set[str] = (source)

Undocumented

Value

set(['typing.Any',
     'typing.Callable',
     'typing.Dict',
     'typing.Iterable',
     'typing.Iterator',
     'typing.List',
     'typing.Optional',
...