[MAINTENANCE] move prepare_prior_versions to allow one version at a t…

…ime (#9246)

docs/docs_build.py

@@ -13,7 +13,6 @@
 
 from docs.docs_version_bucket_info import S3_URL
 from docs.logging import Logger
-from docs.prepare_prior_versions import prepare_prior_versions
 
 if TYPE_CHECKING:
     from invoke.context import Context
@@ -52,16 +51,18 @@ def build_docs_locally(self) -> None:
         self._context.run("yarn start")
 
     def _prepare(self) -> None:
+        from docs.prepare_prior_versions import prepare_prior_versions, Version
+
         """A whole bunch of common work we need"""
         self.logger.print_header("Preparing to build docs...")
-        self._load_files()
+        versions_loaded = self._load_files()
 
         self.logger.print_header(
             "Updating versioned code and docs via prepare_prior_versions.py..."
         )
         # TODO: none of this messing with current directory stuff
         os.chdir("..")
-        prepare_prior_versions()
+        prepare_prior_versions([Version.from_string(v) for v in versions_loaded])
         os.chdir("docusaurus")
         self.logger.print("Updated versioned code and docs")
 
@@ -77,11 +78,13 @@ def _load_zip(self, url: str) -> Generator[zipfile.ZipFile, None, None]:
         with zipfile.ZipFile(zip_data, "r") as zip_ref:
             yield zip_ref
 
-    def _load_files(self) -> None:
+    def _load_files(self) -> List[str]:
         """Load oss_docs_versions zip and relevant versions from github.
 
         oss_docs_versions contains the versioned docs to be used later by prepare_prior_versions, as well
         as the versions.json file, which contains the list of versions that we then download from github.
+
+        Returns a list of verions loaded.
         """
 
         if os.path.exists("versioned_code"):
@@ -108,6 +111,7 @@ def _load_files(self) -> None:
                     self._current_directory / f"versioned_code/version-{version}"
                 )
                 shutil.move(str(old_location), str(new_location))
+        return versions
 
     def _invoke_api_docs(self) -> None:
         """Invokes the invoke api-docs command.