CLN: address FIXME/TODO/XXX comments (#33858)

Author: jbrockmendel

ci/setup_env.sh

@@ -128,7 +128,7 @@ conda list pandas
 echo "[Build extensions]"
 python setup.py build_ext -q -i -j2
 
-# XXX: Some of our environments end up with old versions of pip (10.x)
+# TODO: Some of our environments end up with old versions of pip (10.x)
 # Adding a new enough version of pip to the requirements explodes the
 # solve time. Just using pip to update itself.
 # - py35_macos

pandas/_libs/src/parser/tokenizer.h

@@ -52,8 +52,8 @@ See LICENSE for the license
 #define PARSER_OUT_OF_MEMORY -1
 
 /*
- *  XXX Might want to couple count_rows() with read_rows() to avoid duplication
- *      of some file I/O.
+ *  TODO: Might want to couple count_rows() with read_rows() to avoid
+ *        duplication of some file I/O.
  */
 
 typedef enum {

pandas/_libs/tslibs/strptime.pyx

@@ -544,7 +544,7 @@ class TimeRE(dict):
             'w': r"(?P<w>[0-6])",
             # W is set below by using 'U'
             'y': r"(?P<y>\d\d)",
-            # XXX: Does 'Y' need to worry about having less or more than
+            # TODO: Does 'Y' need to worry about having less or more than
             #     4 digits?
             'Y': r"(?P<Y>\d\d\d\d)",
             'z': r"(?P<z>[+-]\d\d:?[0-5]\d(:?[0-5]\d(\.\d{1,6})?)?|Z)",

pandas/core/algorithms.py

@@ -142,6 +142,7 @@ def _ensure_data(values, dtype=None):
             if values.ndim > 1 and is_datetime64_ns_dtype(values):
                 # Avoid calling the DatetimeIndex constructor as it is 1D only
                 # Note: this is reached by DataFrame.rank calls GH#27027
+                # TODO(EA2D): special case not needed with 2D EAs
                 asi8 = values.view("i8")
                 dtype = values.dtype
                 return asi8, dtype

pandas/core/arrays/sparse/array.py

@@ -335,7 +335,7 @@ def __init__(
         # TODO: disentangle the fill_value dtype inference from
         # dtype inference
         if data is None:
-            # XXX: What should the empty dtype be? Object or float?
+            # TODO: What should the empty dtype be? Object or float?
             data = np.array([], dtype=dtype)
 
         if not is_array_like(data):

pandas/core/dtypes/concat.py

@@ -178,6 +178,7 @@ def concat_categorical(to_concat, axis: int = 0):
     ]
     result = concat_compat(to_concat)
     if axis == 1:
+        # TODO(EA2D): not necessary with 2D EAs
         result = result.reshape(1, len(result))
     return result
 

pandas/core/groupby/generic.py

@@ -1129,6 +1129,7 @@ def _cython_agg_blocks(
                     # e.g. block.values was an IntegerArray
                     # (1, N) case can occur if block.values was Categorical
                     #  and result is ndarray[object]
+                    # TODO(EA2D): special casing not needed with 2D EAs
                     assert result.ndim == 1 or result.shape[0] == 1
                     try:
                         # Cast back if feasible

pandas/core/groupby/ops.py

@@ -476,8 +476,8 @@ def _cython_operation(
 
         if is_datetime64tz_dtype(values.dtype):
             # Cast to naive; we'll cast back at the end of the function
-            # TODO: possible need to reshape?  kludge can be avoided when
-            #  2D EA is allowed.
+            # TODO: possible need to reshape?
+            # TODO(EA2D):kludge can be avoided when 2D EA is allowed.
             values = values.view("M8[ns]")
 
         is_datetimelike = needs_i8_conversion(values.dtype)
@@ -717,7 +717,7 @@ def _aggregate_series_pure_python(
                 if isinstance(res, (Series, Index, np.ndarray)):
                     if len(res) == 1:
                         # e.g. test_agg_lambda_with_timezone lambda e: e.head(1)
-                        # FIXME: are we potentially losing import res.index info?
+                        # FIXME: are we potentially losing important res.index info?
                         res = res.item()
                     else:
                         raise ValueError("Function does not reduce")

pandas/core/internals/blocks.py

@@ -1721,7 +1721,7 @@ def take_nd(
         return self.make_block_same_class(new_values, new_mgr_locs)
 
     def _can_hold_element(self, element: Any) -> bool:
-        # XXX: We may need to think about pushing this onto the array.
+        # TODO: We may need to think about pushing this onto the array.
         # We're doing the same as CategoricalBlock here.
         return True
 

pandas/core/internals/concat.py

@@ -218,6 +218,7 @@ def is_na(self):
         elif is_sparse(self.block.values.dtype):
             return False
         elif self.block.is_extension:
+            # TODO(EA2D): no need for special case with 2D EAs
             values_flat = values
         else:
             values_flat = values.ravel(order="K")