Repository: pypa/pip
File: src/pip/_internal/req/req_install.py (Python)

Code before:
        # The static build requirements (from pyproject.toml)
        self.pyproject_requires: Optional[List[str]] = None

        # Build requirements that we will check are available
        self.requirements_to_check: List[str] = []

        # The PEP 517 backend we should use to build the project
        self.pep517_backend: Optional[BuildBackendHookCaller] = None

        # Are we using PEP 517 for this requirement?
        # After pyproject.toml has been loaded, the only valid values are True
        # and False. Before loading, None is valid (meaning "use the default").
        # Setting an explicit value before loading pyproject.toml is supported,
        # but after loading this flag should be treated as read only.
        self.use_pep517 = use_pep517

        # This requirement needs more preparation before it can be built
        self.needs_more_preparation = False

        # This requirement needs to be unpacked before it can be installed.
        self._archive_source: Optional[Path] = None

    def __str__(self) -> str:
        if self.req:
            s = str(self.req)
            if self.link:
                s += " from {}".format(redact_auth_from_url(self.link.url))
        elif self.link:
            s = redact_auth_from_url(self.link.url)
        else:
            s = "<InstallRequirement>"
        if self.satisfied_by is not None:
            if self.satisfied_by.location is not None:
                location = display_path(self.satisfied_by.location)
            else:
                location = "<memory>"
            s += f" in {location}"
        if self.comes_from:
            if isinstance(self.comes_from, str):
                comes_from: Optional[str] = self.comes_from
            else:
                comes_from = self.comes_from.from_path()
            if comes_from:
                s += f" (from {comes_from})"
        return s

    def __repr__(self) -> str:
        return "<{} object: {} editable={!r}>".format(
            self.__class__.__name__, str(self), self.editable
        )


Review comment (bug):
Note to reviewers: this specific change is unrelated to the bug fix, but this should prevent similar issues popping up elsewhere.

Code after:

        # The static build requirements (from pyproject.toml)
        self.pyproject_requires: Optional[List[str]] = None

        # Build requirements that we will check are available
        self.requirements_to_check: List[str] = []

        # The PEP 517 backend we should use to build the project
        self.pep517_backend: Optional[BuildBackendHookCaller] = None

        # Are we using PEP 517 for this requirement?
        # After pyproject.toml has been loaded, the only valid values are True
        # and False. Before loading, None is valid (meaning "use the default").
        # Setting an explicit value before loading pyproject.toml is supported,
        # but after loading this flag should be treated as read only.
        self.use_pep517 = use_pep517

        # This requirement needs more preparation before it can be built
        self.needs_more_preparation = False

        # This requirement needs to be unpacked before it can be installed.
        self._archive_source: Optional[Path] = None

    def __str__(self) -> str:
        if self.req:
            s = redact_auth_from_requirement(self.req)
            if self.link:
                s += " from {}".format(redact_auth_from_url(self.link.url))
        elif self.link:
            s = redact_auth_from_url(self.link.url)
        else:
            s = "<InstallRequirement>"
        if self.satisfied_by is not None:
            if self.satisfied_by.location is not None:
                location = display_path(self.satisfied_by.location)
            else:
                location = "<memory>"
            s += f" in {location}"
        if self.comes_from:
            if isinstance(self.comes_from, str):
                comes_from: Optional[str] = self.comes_from
            else:
                comes_from = self.comes_from.from_path()
            if comes_from:
                s += f" (from {comes_from})"
        return s

    def __repr__(self) -> str:
        return "<{} object: {} editable={!r}>".format(
            self.__class__.__name__, str(self), self.editable
        )