pylint/checkers/base_checker.py

# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
# For details: https://github.com/pylint-dev/pylint/blob/main/LICENSE
# Copyright (c) https://github.com/pylint-dev/pylint/blob/main/CONTRIBUTORS.txt

from __future__ import annotations

import abc
import functools
from collections.abc import Iterable, Sequence
from inspect import cleandoc
from tokenize import TokenInfo
from typing import TYPE_CHECKING, Any

from astroid import nodes

from pylint.config.arguments_provider import _ArgumentsProvider
from pylint.constants import _MSG_ORDER, MAIN_CHECKER_NAME, WarningScope
from pylint.exceptions import InvalidMessageError
from pylint.interfaces import Confidence
from pylint.message.message_definition import MessageDefinition
from pylint.typing import (
    ExtraMessageOptions,
    MessageDefinitionTuple,
    OptionDict,
    Options,
    ReportsCallable,
)
from pylint.utils import get_rst_section, get_rst_title

if TYPE_CHECKING:
    from pylint.lint import PyLinter


@functools.total_ordering
class BaseChecker(_ArgumentsProvider):
    # checker name (you may reuse an existing one)
    name: str = ""
    # ordered list of options to control the checker behaviour
    options: Options = ()
    # messages issued by this checker
    msgs: dict[str, MessageDefinitionTuple] = {}
    # reports issued by this checker
    reports: tuple[tuple[str, str, ReportsCallable], ...] = ()
    # mark this checker as enabled or not.
    enabled: bool = True

    def __init__(self, linter: PyLinter) -> None:
        """Checker instances should have the linter as argument."""
        if self.name is not None:
            self.name = self.name.lower()
        self.linter = linter
        _ArgumentsProvider.__init__(self, linter)

    def __gt__(self, other: Any) -> bool:
        """Permits sorting checkers for stable doc and tests.

        The main checker is always the first one, then builtin checkers in alphabetical
        order, then extension checkers in alphabetical order.
        """
        if not isinstance(other, BaseChecker):
            return False
        if self.name == MAIN_CHECKER_NAME:
            return False
        if other.name == MAIN_CHECKER_NAME:
            return True
        self_is_builtin = type(self).__module__.startswith("pylint.checkers")
        if self_is_builtin ^ type(other).__module__.startswith("pylint.checkers"):
            return not self_is_builtin
        return self.name > other.name

    def __eq__(self, other: object) -> bool:
        """Permit to assert Checkers are equal."""
        if not isinstance(other, BaseChecker):
            return False
        return f"{self.name}{self.msgs}" == f"{other.name}{other.msgs}"

    def __hash__(self) -> int:
        """Make Checker hashable."""
        return hash(f"{self.name}{self.msgs}")

    def __repr__(self) -> str:
        status = "Checker" if self.enabled else "Disabled checker"
        msgs = "', '".join(self.msgs.keys())
        return f"{status} '{self.name}' (responsible for '{msgs}')"

    def __str__(self) -> str:
        """This might be incomplete because multiple classes inheriting BaseChecker
        can have the same name.

        See: MessageHandlerMixIn.get_full_documentation()
        """
        return self.get_full_documentation(
            msgs=self.msgs, options=self._options_and_values(), reports=self.reports
        )

    def get_full_documentation(
        self,
        msgs: dict[str, MessageDefinitionTuple],
        options: Iterable[tuple[str, OptionDict, Any]],
        reports: Sequence[tuple[str, str, ReportsCallable]],
        doc: str | None = None,
        module: str | None = None,
        show_options: bool = True,
    ) -> str:
        result = ""
        checker_title = f"{self.name.replace('_', ' ').title()} checker"
        if module:
            # Provide anchor to link against
            result += f".. _{module}:\n\n"
        result += f"{get_rst_title(checker_title, '~')}\n"
        if module:
            result += f"This checker is provided by ``{module}``.\n"
        result += f"Verbatim name of the checker is ``{self.name}``.\n\n"
        if doc:
            # Provide anchor to link against
            result += get_rst_title(f"{checker_title} Documentation", "^")
            result += f"{cleandoc(doc)}\n\n"
        # options might be an empty generator and not be False when cast to boolean
        options_list = list(options)
        if options_list:
            if show_options:
                result += get_rst_title(f"{checker_title} Options", "^")
                result += f"{get_rst_section(None, options_list)}\n"
            else:
                result += f"See also :ref:`{self.name} checker's options' documentation <{self.name}-options>`\n\n"
        if msgs:
            result += get_rst_title(f"{checker_title} Messages", "^")
            for msgid, msg in sorted(
                msgs.items(), key=lambda kv: (_MSG_ORDER.index(kv[0][0]), kv[1])
            ):
                msg_def = self.create_message_definition_from_tuple(msgid, msg)
                result += f"{msg_def.format_help(checkerref=False)}\n"
            result += "\n"
        if reports:
            result += get_rst_title(f"{checker_title} Reports", "^")
            for report in reports:
                result += f":{report[0]}: {report[1]}\n"
            result += "\n"
        result += "\n"
        return result

    def add_message(
        self,
        msgid: str,
        line: int | None = None,
        node: nodes.NodeNG | None = None,
        args: Any = None,
        confidence: Confidence | None = None,
        col_offset: int | None = None,
        end_lineno: int | None = None,
        end_col_offset: int | None = None,
    ) -> None:
        self.linter.add_message(
            msgid, line, node, args, confidence, col_offset, end_lineno, end_col_offset
        )

    def check_consistency(self) -> None:
        """Check the consistency of msgid.

        msg ids for a checker should be a string of len 4, where the two first
        characters are the checker id and the two last the msg id in this
        checker.

        :raises InvalidMessageError: If the checker id in the messages are not
        always the same.
        """
        checker_id = None
        existing_ids = []
        for message in self.messages:
            # Id's for shared messages such as the 'deprecated-*' messages
            # can be inconsistent with their checker id.
            if message.shared:
                continue
            if checker_id is not None and checker_id != message.msgid[1:3]:
                error_msg = "Inconsistent checker part in message id "
                error_msg += f"'{message.msgid}' (expected 'x{checker_id}xx' "
                error_msg += f"because we already had {existing_ids})."
                raise InvalidMessageError(error_msg)
            checker_id = message.msgid[1:3]
            existing_ids.append(message.msgid)

    def create_message_definition_from_tuple(
        self, msgid: str, msg_tuple: MessageDefinitionTuple
    ) -> MessageDefinition:
        if isinstance(self, (BaseTokenChecker, BaseRawFileChecker)):
            default_scope = WarningScope.LINE
        else:
            default_scope = WarningScope.NODE
        options: ExtraMessageOptions = {}
        if len(msg_tuple) == 4:
            (msg, symbol, descr, msg_options) = msg_tuple
            options = ExtraMessageOptions(**msg_options)
        elif len(msg_tuple) == 3:
            (msg, symbol, descr) = msg_tuple
        else:
            error_msg = """Messages should have a msgid, a symbol and a description. Something like this :

"W1234": (
    "message",
    "message-symbol",
    "Message description with detail.",
    ...
),
"""
            raise InvalidMessageError(error_msg)
        options.setdefault("scope", default_scope)
        return MessageDefinition(self, msgid, msg, descr, symbol, **options)

    @property
    def messages(self) -> list[MessageDefinition]:
        return [
            self.create_message_definition_from_tuple(msgid, msg_tuple)
            for msgid, msg_tuple in sorted(self.msgs.items())
        ]

    def open(self) -> None:
        """Called before visiting project (i.e. set of modules)."""

    def close(self) -> None:
        """Called after visiting project (i.e set of modules)."""

    def get_map_data(self) -> Any:
        return None

    # pylint: disable-next=unused-argument
    def reduce_map_data(self, linter: PyLinter, data: list[Any]) -> None:
        return None


class BaseTokenChecker(BaseChecker):
    """Base class for checkers that want to have access to the token stream."""

    @abc.abstractmethod
    def process_tokens(self, tokens: list[TokenInfo]) -> None:
        """Should be overridden by subclasses."""
        raise NotImplementedError()


class BaseRawFileChecker(BaseChecker):
    """Base class for checkers which need to parse the raw file."""

    @abc.abstractmethod
    def process_module(self, node: nodes.Module) -> None:
        """Process a module.

        The module's content is accessible via ``astroid.stream``
        """
        raise NotImplementedError()