Add deepcopy and pickle support to figures and graph objects (#1191)

* Allow kwargs to override properties in codegen validator subclasses

This will make it easier to implement generic validator deepcopy support

* Make all validators support deepcopy

* Avoid infinite loops when checking for existence of _subplotid_props in Layout

* Add __reduce__ methods to BaseFigure and BasePlotlyType

This method provides pickle and deep copy support

* Add tests for deepcopy and pickle support

Author: jonmmease

Diff for: _plotly_utils/basevalidators.py

@@ -3,6 +3,7 @@
 import textwrap
 import uuid
 from importlib import import_module
+import copy
 
 import io
 from copy import deepcopy
@@ -373,6 +374,7 @@ def __init__(self,
         self.array_ok = array_ok
         # coerce_number is rarely used and not implemented
         self.coerce_number = coerce_number
+        self.kwargs = kwargs
 
         # Handle regular expressions
         # --------------------------
@@ -398,6 +400,17 @@ def __init__(self,
                 self.val_regexs.append(None)
                 self.regex_replacements.append(None)
 
+    def __deepcopy__(self, memodict={}):
+        """
+        A custom deepcopy method is needed here because compiled regex
+        objects don't support deepcopy
+        """
+        cls = self.__class__
+        return cls(
+            self.plotly_name,
+            self.parent_name,
+            values=self.values)
+
     @staticmethod
     def build_regex_replacement(regex_str):
         # Example: regex_str == r"^y([2-9]|[1-9][0-9]+)?$"

Diff for: codegen/validators.py

@@ -63,7 +63,7 @@ def __init__(self, plotly_name={params['plotly_name']},
             continue
 
         buffer.write(f""",
-                 {attr_name}={attr_val}""")
+                 {attr_name}=kwargs.pop('{attr_name}', {attr_val})""")
 
     buffer.write(f""",
         **kwargs""")