BUG: Fix Index.get_level_values() mishandling of boolean, pd.NA, np.nan, and pd.NaT levels

Author: whyvineet

pandas/_libs/__init__.py

@@ -1,4 +1,5 @@
 __all__ = [
+    "NA",
     "Interval",
     "NaT",
     "NaTType",
@@ -15,6 +16,7 @@
 # see pandas_datetime_exec in pd_datetime.c
 import pandas._libs.pandas_parser  # isort: skip # type: ignore[reportUnusedImport]
 import pandas._libs.pandas_datetime  # noqa: F401 # isort: skip # type: ignore[reportUnusedImport]
+from pandas._libs.missing import NA
 from pandas._libs.interval import Interval
 from pandas._libs.tslibs import (
     NaT,

pandas/core/indexes/base.py

@@ -26,6 +26,7 @@
 )
 
 from pandas._libs import (
+    NA,
     NaT,
     algos as libalgos,
     index as libindex,
@@ -2084,7 +2085,7 @@ def _validate_index_level(self, level) -> None:
         verification must be done like in MultiIndex.
 
         """
-        if isinstance(level, int):
+        if type(level) is int:
             if level < 0 and level != -1:
                 raise IndexError(
                     "Too many levels: Index has only 1 level, "
@@ -2094,10 +2095,25 @@ def _validate_index_level(self, level) -> None:
                 raise IndexError(
                     f"Too many levels: Index has only 1 level, not {level + 1}"
                 )
-        elif level != self.name:
-            raise KeyError(
-                f"Requested level ({level}) does not match index name ({self.name})"
-            )
+
+        else:
+            if level is NA:
+                raise KeyError(
+                    "Requested level is pandas.NA, which is not a valid index name"
+                )
+            if level is NaT:
+                raise KeyError(
+                    "Requested level is pandas.NaT, which is not a valid index name"
+                )
+            if isinstance(level, float) and np.isnan(level):
+                raise KeyError(
+                    "Requested level is NaN, which is not a valid index name"
+                )
+
+            if level != self.name:
+                raise KeyError(
+                    f"Requested level ({level}) does not match index name ({self.name})"
+                )
 
     def _get_level_number(self, level) -> int:
         self._validate_index_level(level)