Config adapter for pytext XLM (#1172)

Summary:
Pull Request resolved: #1172

Config adapter for adding Union in XLMModel class from D18107524

The Encoder is a super type and will always have a class specified, adding this for the Tensorizer.

Reviewed By: rutyrinott

Differential Revision: D18717196

fbshipit-source-id: 50839d97220e77ed08a30345a4e6a293e0213a6c

pytext/config/config_adapter.py

@@ -653,6 +653,22 @@ def rename_fl_task(json_config):
     return json_config
 
 
+@register_adapter(from_version=18)
+def upgrade_if_xlm(json_config):
+    """
+    Make `XLMModel` Union changes for encoder and tokens config.
+    Since they are now unions, insert the old class into the config if
+    no class name is mentioned.
+    """
+    _, _, model = find_parameter(json_config, "task.model")
+    if model and "XLMModel" in model:
+        _, inputs, tokens = find_parameter(json_config, "task.model.inputs.tokens")
+        inputs["tokens"] = {}
+        inputs["tokens"]["XLMTensorizer"] = tokens
+
+    return json_config
+
+
 def upgrade_one_version(json_config):
     current_version = json_config.get("version", 0)
     adapter = ADAPTERS.get(current_version)

pytext/config/pytext_config.py

@@ -154,4 +154,4 @@ class LogitsConfig(TestConfig):
     dump_raw_input: bool = False
 
 
-LATEST_VERSION = 18
+LATEST_VERSION = 19