Add a DeprecationWarning about deprecating the list API for Component…

…Graphs (#2488)


* filter warnings unless for pipeline init

docs/source/release_notes.rst

@@ -10,6 +10,7 @@ Release Notes
         * Added custom exception message for partial dependence on features with scales that are too small :pr:`2455`
         * Updated to work with Pandas 1.3.0 :pr:`2442`
     * Changes
+        * Added a ``DeprecationWarning`` about deprecating the list API for ``ComponentGraph`` :pr:`2488`
     * Documentation Changes
         * Moved docstrings from ``__init__`` to class pages, added missing docstrings for missing classes, and updated missing default values :pr:`2452`
     * Testing Changes

evalml/pipelines/component_graph.py

@@ -1,3 +1,5 @@
+import warnings
+
 import networkx as nx
 import pandas as pd
 import woodwork as ww
@@ -101,6 +103,10 @@ def from_list(cls, component_list, random_seed=0):
             component_list (list): String names or ComponentBase subclasses in
                                    an order that represents a valid linear graph
         """
+        warnings.warn(
+            "ComponentGraph.from_list will be deprecated in the next release. Please use a dictionary to specify your graph instead.",
+            DeprecationWarning,
+        )
         component_dict = {}
         previous_component = None
 

evalml/pipelines/pipeline_base.py

@@ -3,6 +3,7 @@
 import os
 import sys
 import traceback
+import warnings
 from abc import ABC, abstractmethod
 from collections import OrderedDict
 
@@ -66,9 +67,14 @@ def __init__(
         self.random_seed = random_seed
 
         if isinstance(component_graph, list):  # Backwards compatibility
-            self.component_graph = ComponentGraph().from_list(
-                component_graph, random_seed=self.random_seed
-            )
+            with warnings.catch_warnings():
+                warnings.filterwarnings(
+                    "ignore",
+                    message="ComponentGraph.from_list will be deprecated in the next release. Please use a dictionary to specify your graph instead.",
+                )
+                self.component_graph = ComponentGraph().from_list(
+                    component_graph, random_seed=self.random_seed
+                )
         elif isinstance(component_graph, dict):
             self.component_graph = ComponentGraph(
                 component_dict=component_graph, random_seed=self.random_seed

evalml/tests/pipeline_tests/test_component_graph.py

@@ -1,3 +1,4 @@
+import warnings
 from datetime import datetime, timedelta
 from unittest.mock import patch
 
@@ -289,6 +290,16 @@ def test_from_list_repeat_component():
     assert component_graph.get_component("One Hot Encoder_2").parameters["top_n"] == 11
 
 
+def test_component_graph_from_list_deprecation_warning():
+    component_list = ["Imputer", "One Hot Encoder", RandomForestClassifier]
+    with warnings.catch_warnings(record=True) as w:
+        warnings.simplefilter("always")
+        ComponentGraph.from_list(component_list)
+        assert len(w) == 1
+        assert issubclass(w[-1].category, DeprecationWarning)
+        assert "deprecated" in str(w[-1].message)
+
+
 def test_instantiate_with_parameters(example_graph):
     graph = example_graph
     component_graph = ComponentGraph(graph)