BUG: also copy uuid in Styler.copy (pandas-dev#43044)

Author: attack68

doc/source/whatsnew/v1.4.0.rst

@@ -239,6 +239,7 @@ Categorical
 - Bug in :meth:`Series.where` with ``CategoricalDtype`` when passing a dtype-incompatible value raising ``ValueError`` instead of ``TypeError`` (:issue:`41919`)
 - Bug in :meth:`Categorical.fillna` when passing a dtype-incompatible value raising ``ValueError`` instead of ``TypeError`` (:issue:`41919`)
 - Bug in :meth:`Categorical.fillna` with a tuple-like category raising ``ValueError`` instead of ``TypeError`` when filling with a non-category tuple (:issue:`41919`)
+- Bug in :meth:`.Styler.copy` where ``uuid`` was not previously copied (:issue:`40675`)
 -
 
 Datetimelike

pandas/io/formats/style.py

@@ -1079,14 +1079,15 @@ def _copy(self, deepcopy: bool = False) -> Styler:
         # GH 40675
         styler = Styler(
             self.data,  # populates attributes 'data', 'columns', 'index' as shallow
-            uuid_len=self.uuid_len,
         )
         shallow = [  # simple string or boolean immutables
             "hide_index_",
             "hide_columns_",
             "table_attributes",
             "cell_ids",
             "caption",
+            "uuid",
+            "uuid_len",
         ]
         deep = [  # nested lists or dicts
             "_display_funcs",

pandas/io/formats/style_render.py

@@ -89,8 +89,8 @@ def __init__(
         self.columns: Index = data.columns
         if not isinstance(uuid_len, int) or not uuid_len >= 0:
             raise TypeError("``uuid_len`` must be an integer in range [0, 32].")
-        self.uuid_len = min(32, uuid_len)
-        self.uuid = uuid or uuid4().hex[: self.uuid_len]
+        self.uuid = uuid or uuid4().hex[: min(32, uuid_len)]
+        self.uuid_len = len(self.uuid)
         self.table_styles = table_styles
         self.table_attributes = table_attributes
         self.caption = caption

pandas/tests/io/formats/style/test_style.py

@@ -203,7 +203,6 @@ def test_copy(comprehensive, render, deepcopy, mi_styler, mi_styler_comp):
     excl = [
         "na_rep",  # deprecated
         "precision",  # deprecated
-        "uuid",  # special
         "cellstyle_map",  # render time vars..
         "cellstyle_map_columns",
         "cellstyle_map_index",
@@ -217,6 +216,7 @@ def test_copy(comprehensive, render, deepcopy, mi_styler, mi_styler_comp):
             "columns",
             "index",
             "uuid_len",
+            "uuid",
             "caption",
             "cell_ids",
             "hide_index_",
@@ -242,7 +242,7 @@ def test_clear(mi_styler_comp):
     # to ensure proper testing of the 'copy', 'clear', 'export' methods with new feature
     # GH 40675
     styler = mi_styler_comp
-    styler.to_html()  # new attrs maybe created on render
+    styler._compute()  # execute applied methods
 
     clean_copy = Styler(styler.data, uuid=styler.uuid)
 
@@ -251,7 +251,7 @@ def test_clear(mi_styler_comp):
         "index",
         "columns",
         "uuid",
-        "uuid_len",
+        "uuid_len",  # uuid is set to be the same on styler and clean_copy
         "cell_ids",
         "cellstyle_map",  # execution time only
         "cellstyle_map_columns",  # execution time only