Add vendored packages back

lib/spack/external/_vendoring/attr/_compat.py

@@ -0,0 +1,185 @@
+# SPDX-License-Identifier: MIT
+
+
+import inspect
+import platform
+import sys
+import threading
+import types
+import warnings
+
+from collections.abc import Mapping, Sequence  # noqa
+
+
+PYPY = platform.python_implementation() == "PyPy"
+PY36 = sys.version_info[:2] >= (3, 6)
+HAS_F_STRINGS = PY36
+PY310 = sys.version_info[:2] >= (3, 10)
+
+
+if PYPY or PY36:
+    ordered_dict = dict
+else:
+    from collections import OrderedDict
+
+    ordered_dict = OrderedDict
+
+
+def just_warn(*args, **kw):
+    warnings.warn(
+        "Running interpreter doesn't sufficiently support code object "
+        "introspection.  Some features like bare super() or accessing "
+        "__class__ will not work with slotted classes.",
+        RuntimeWarning,
+        stacklevel=2,
+    )
+
+
+class _AnnotationExtractor:
+    """
+    Extract type annotations from a callable, returning None whenever there
+    is none.
+    """
+
+    __slots__ = ["sig"]
+
+    def __init__(self, callable):
+        try:
+            self.sig = inspect.signature(callable)
+        except (ValueError, TypeError):  # inspect failed
+            self.sig = None
+
+    def get_first_param_type(self):
+        """
+        Return the type annotation of the first argument if it's not empty.
+        """
+        if not self.sig:
+            return None
+
+        params = list(self.sig.parameters.values())
+        if params and params[0].annotation is not inspect.Parameter.empty:
+            return params[0].annotation
+
+        return None
+
+    def get_return_type(self):
+        """
+        Return the return type if it's not empty.
+        """
+        if (
+            self.sig
+            and self.sig.return_annotation is not inspect.Signature.empty
+        ):
+            return self.sig.return_annotation
+
+        return None
+
+
+def make_set_closure_cell():
+    """Return a function of two arguments (cell, value) which sets
+    the value stored in the closure cell `cell` to `value`.
+    """
+    # pypy makes this easy. (It also supports the logic below, but
+    # why not do the easy/fast thing?)
+    if PYPY:
+
+        def set_closure_cell(cell, value):
+            cell.__setstate__((value,))
+
+        return set_closure_cell
+
+    # Otherwise gotta do it the hard way.
+
+    # Create a function that will set its first cellvar to `value`.
+    def set_first_cellvar_to(value):
+        x = value
+        return
+
+        # This function will be eliminated as dead code, but
+        # not before its reference to `x` forces `x` to be
+        # represented as a closure cell rather than a local.
+        def force_x_to_be_a_cell():  # pragma: no cover
+            return x
+
+    try:
+        # Extract the code object and make sure our assumptions about
+        # the closure behavior are correct.
+        co = set_first_cellvar_to.__code__
+        if co.co_cellvars != ("x",) or co.co_freevars != ():
+            raise AssertionError  # pragma: no cover
+
+        # Convert this code object to a code object that sets the
+        # function's first _freevar_ (not cellvar) to the argument.
+        if sys.version_info >= (3, 8):
+
+            def set_closure_cell(cell, value):
+                cell.cell_contents = value
+
+        else:
+            args = [co.co_argcount]
+            args.append(co.co_kwonlyargcount)
+            args.extend(
+                [
+                    co.co_nlocals,
+                    co.co_stacksize,
+                    co.co_flags,
+                    co.co_code,
+                    co.co_consts,
+                    co.co_names,
+                    co.co_varnames,
+                    co.co_filename,
+                    co.co_name,
+                    co.co_firstlineno,
+                    co.co_lnotab,
+                    # These two arguments are reversed:
+                    co.co_cellvars,
+                    co.co_freevars,
+                ]
+            )
+            set_first_freevar_code = types.CodeType(*args)
+
+            def set_closure_cell(cell, value):
+                # Create a function using the set_first_freevar_code,
+                # whose first closure cell is `cell`. Calling it will
+                # change the value of that cell.
+                setter = types.FunctionType(
+                    set_first_freevar_code, {}, "setter", (), (cell,)
+                )
+                # And call it to set the cell.
+                setter(value)
+
+        # Make sure it works on this interpreter:
+        def make_func_with_cell():
+            x = None
+
+            def func():
+                return x  # pragma: no cover
+
+            return func
+
+        cell = make_func_with_cell().__closure__[0]
+        set_closure_cell(cell, 100)
+        if cell.cell_contents != 100:
+            raise AssertionError  # pragma: no cover
+
+    except Exception:
+        return just_warn
+    else:
+        return set_closure_cell
+
+
+set_closure_cell = make_set_closure_cell()
+
+# Thread-local global to track attrs instances which are already being repr'd.
+# This is needed because there is no other (thread-safe) way to pass info
+# about the instances that are already being repr'd through the call stack
+# in order to ensure we don't perform infinite recursion.
+#
+# For instance, if an instance contains a dict which contains that instance,
+# we need to know that we're already repr'ing the outside instance from within
+# the dict's repr() call.
+#
+# This lives here rather than in _make.py so that the functions in _make.py
+# don't have a direct reference to the thread-local in their globals dict.
+# If they have such a reference, it breaks cloudpickle.
+repr_context = threading.local()