This improves the performance of deployment, by aggregating uncached select calls for vars generate into two batches.
batch 1: Get all generators of all machines
batch 2: get all final scripts for generators which need to run
For either(oneOf) types, we skip introspection as we cannot
determine which branch of the union was taken without more context
This *should* be safe, as it can currently mostly be triggered through
The `extraModules` setting of inventory modules.
Example:
```
importer.roles.default.extraModules = [
../../modules/nixos/common.nix
];
```
Error Message:
```
Traceback (most recent call last):
File "/nix/store/zaz4r4fic03m4whgz46p5jjszzlkq694-clan-cli/lib/python3.13/site-packages/clan_lib/templates/handler.py", line 91, in machine_template
yield dst_machine_dir
File "/nix/store/zaz4r4fic03m4whgz46p5jjszzlkq694-clan-cli/lib/python3.13/site-packages/clan_cli/machines/create.py", line 95, in create_machine
inventory_store.write(inventory, message=f"machine '{machine_name}'")
~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/nix/store/zaz4r4fic03m4whgz46p5jjszzlkq694-clan-cli/lib/python3.13/site-packages/clan_lib/persist/inventory_store.py", line 269, in write
write_info = self._write_map()
File "/nix/store/zaz4r4fic03m4whgz46p5jjszzlkq694-clan-cli/lib/python3.13/site-packages/clan_lib/persist/inventory_store.py", line 214, in _write_map
current_priority = self._get_inventory_current_priority()
File "/nix/store/zaz4r4fic03m4whgz46p5jjszzlkq694-clan-cli/lib/python3.13/site-packages/clan_lib/persist/inventory_store.py", line 206, in _get_inventory_current_priority
return self._flake.select("clanInternals.inventoryClass.introspection")
~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/nix/store/zaz4r4fic03m4whgz46p5jjszzlkq694-clan-cli/lib/python3.13/site-packages/clan_lib/flake/flake.py", line 1129, in select
self.get_from_nix([selector])
~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
File "/nix/store/zaz4r4fic03m4whgz46p5jjszzlkq694-clan-cli/lib/python3.13/site-packages/clan_lib/flake/flake.py", line 1054, in get_from_nix
raise ClanSelectError(
...<3 lines>...
) from e
clan_lib.flake.flake.ClanSelectError: Error on: $ clan select 'clanInternals.inventoryClass.introspection'
Reason: Yet Unsupported type: either
Removing left-over machine directory: /tmp/hyperconfig/machines/trooo
Error on: $ clan select 'clanInternals.inventoryClass.introspection'
Reason: Yet Unsupported type: either
```
Closes: #5387
Add documentation explaining that services defining vars need to run
update-vars before tests can execute. Clarifies how `clan.directory`
determines where vars are generated and loaded from during testing.
Closes: #5380
Resolves the "RuntimeError: generator didn't stop after throw()" issue
by replacing the generator-based @contextmanager with an explicit class.
This maintains backward compatibility through a factory function.
