cli[patch]: Ignore imports that change the name of the class (#21026)

Not currently handeled by migration script

libs/cli/langchain_cli/namespaces/migrate/codemods/migrations/langchain_to_core.json

@@ -2123,4 +2123,4 @@
     "langchain.vectorstores.singlestoredb.SingleStoreDBRetriever",
     "langchain_core.vectorstores.VectorStoreRetriever"
   ]
-]
+]

libs/cli/langchain_cli/namespaces/migrate/codemods/replace_imports.py

@@ -29,7 +29,17 @@ def _load_migrations_by_file(path: str):
     migrations_path = os.path.join(HERE, "migrations", path)
     with open(migrations_path, "r", encoding="utf-8") as f:
         data = json.load(f)
-    return data
+
+    # new migrations
+    new_migrations = []
+    for migration in data:
+        old = migration[0].split(".")[-1]
+        new = migration[1].split(".")[-1]
+
+        if old == new:
+            new_migrations.append(migration)
+
+    return new_migrations
 
 
 T = TypeVar("T")

libs/cli/tests/unit_tests/migrate/test_code_migrations.py

@@ -0,0 +1,31 @@
+"""Verify that the code migrations do not involve alias changes.
+
+Migration script only updates imports not the rest of the code that uses the
+import.
+"""
+from langchain_cli.namespaces.migrate.codemods.replace_imports import (
+    RULE_TO_PATHS,
+    _load_migrations_from_fixtures,
+)
+
+
+def test_migration_files() -> None:
+    """Generate a codemod to replace imports."""
+    errors = []
+
+    for paths in list(RULE_TO_PATHS.values()):
+        for path in paths:
+            migrations = _load_migrations_from_fixtures([path])
+
+            for migration in migrations:
+                old = migration[0].split(".")[-1]
+                new = migration[1].split(".")[-1]
+                if old != new:
+                    errors.append((path, migration))
+
+    if errors:
+        raise ValueError(
+            f"Migration involves an alias change: {errors}. The "
+            f"migration script does not currently support "
+            f"corresponding code changes."
+        )