cli[minor]: Add script to generate migrations for partner packages (#20932)

Add script to help generate migrations.

This works well for partner packages. Migrations are generated based on run time rather than static analysis (much simpler to get the correct migrations implemented).

The script for generating migrations from langchain to community still needs work.

libs/cli/tests/unit_tests/migrate/generate/test_partner_migrations.py

@@ -0,0 +1,31 @@
+import pytest
+
+from langchain_cli.namespaces.migrate.generate.partner import (
+    get_migrations_for_partner_package,
+)
+
+pytest.importorskip(modname="langchain_openai")
+
+
+def test_generate_migrations() -> None:
+    migrations = get_migrations_for_partner_package("langchain_openai")
+    assert migrations == [
+        ("langchain_community.llms.openai.OpenAI", "langchain_openai.OpenAI"),
+        ("langchain_community.llms.openai.AzureOpenAI", "langchain_openai.AzureOpenAI"),
+        (
+            "langchain_community.embeddings.openai.OpenAIEmbeddings",
+            "langchain_openai.OpenAIEmbeddings",
+        ),
+        (
+            "langchain_community.embeddings.azure_openai.AzureOpenAIEmbeddings",
+            "langchain_openai.AzureOpenAIEmbeddings",
+        ),
+        (
+            "langchain_community.chat_models.openai.ChatOpenAI",
+            "langchain_openai.ChatOpenAI",
+        ),
+        (
+            "langchain_community.chat_models.azure_openai.AzureChatOpenAI",
+            "langchain_openai.AzureChatOpenAI",
+        ),
+    ]

libs/cli/tests/unit_tests/migrate/generate/test_utils.py

@@ -0,0 +1,5 @@
+from langchain_cli.namespaces.migrate.generate.utils import PKGS_ROOT
+
+
+def test_root() -> None:
+    assert PKGS_ROOT.name == "libs"