BUG: Fix case where SlurmExecutor.finalize() is called but no work (#256)

Author: basnijholt

adaptive_scheduler/_executor.py

@@ -36,8 +36,11 @@ def submit(self, fn: Callable[..., Any], /, *args: Any, **kwargs: Any) -> Future
         """Submit a task to the executor."""
 
     @abc.abstractmethod
-    def finalize(self, *, start: bool = True) -> adaptive_scheduler.RunManager:
-        """Finalize the executor and return the RunManager."""
+    def finalize(self, *, start: bool = True) -> adaptive_scheduler.RunManager | None:
+        """Finalize the executor and return the RunManager.
+
+        Returns None if no learners were submitted.
+        """
 
     def map(  # type: ignore[override]
         self,
@@ -408,11 +411,13 @@ def _to_learners(self) -> tuple[list[SequenceLearner], list[Path]]:
                 fnames.append(self.folder / f"{name}-{i}-{uuid.uuid4().hex}.pickle")
         return learners, fnames
 
-    def finalize(self, *, start: bool = True) -> adaptive_scheduler.RunManager:
+    def finalize(self, *, start: bool = True) -> adaptive_scheduler.RunManager | None:
         if self._run_manager is not None:
             msg = "RunManager already initialized. Create a new SlurmExecutor instance."
             raise RuntimeError(msg)
         learners, fnames = self._to_learners()
+        if not learners:
+            return None
         assert self.folder is not None
         self._run_manager = adaptive_scheduler.slurm_run(
             learners=learners,

readthedocs.yml

@@ -5,5 +5,8 @@ build:
     tools:
         python: "mambaforge-4.10"
 
+sphinx:
+    configuration: docs/source/conf.py
+
 conda:
     environment: docs/environment.yml