Method patch

pex/variables.py:365–390

Update the environment for the duration of a context. Any environment variable with a value of `None` will be removed from the environment if present. The rest will be added to the environment or else updated if already present in the environment.

(self, **kw)

    @contextmanager
    def patch(self, **kw):
        # type: (**Optional[str]) -> Iterator[Dict[str, str]]
        """Update the environment for the duration of a context.

        Any environment variable with a value of `None` will be removed from the environment if
        present. The rest will be added to the environment or else updated if already present in
        the environment.
        """
        disable_env = self._maybe_get_bool_var("PEX_DISABLE_VARIABLES", kw)

        old_environ = self._environ
        self._environ = self._environ.copy()
        if disable_env:
            for k in list(self._environ):
                if k != "PEX_DISABLE_VARIABLES" and k.startswith("PEX_"):
                    self._environ.pop(k)
        for k, v in kw.items():
            if v is None:
                self._environ.pop(k, None)
            elif disable_env and k != "PEX_DISABLE_VARIABLES" and k.startswith("PEX_"):
                self._environ.pop(k, None)
            else:
                self._environ[k] = v

        yield self._environ
        self._environ = old_environ

    @defaulted_property(default=False)
    def PEX_DISABLE_VARIABLES(self):