improved

browsergym/experiments/src/browsergym/experiments/benchmark/base.py

@@ -96,57 +96,74 @@ def prepare_backends(self):
             prepare_backend(backend)
             logger.info(f"{backend} backend ready")
 
-    def subset_from_split(
+    def subset_from_split(self, split: Literal["train", "valid", "test"]):
+        split_column = "browsergym_split"
+
+        # check for a split column in metadata
+        if split_column not in self.task_metadata.columns:
+            raise NotImplementedError(
+                f"This benchmark does not provide default train/valid/test splits (missing a {repr(split_column)} column in task metadata)"
+            )
+
+        # recover the target split
+        sub_benchmark = self.subset_from_regexp(split_column, regexp=f"^{split}$")
+        sub_benchmark.name = f"{self.name}_{split}"
+
+        # check that the split exists (non-empty task list)
+        if not sub_benchmark.env_args_list:
+            raise ValueError(f"The default {split} split for this benchmark is empty.")
+
+        return sub_benchmark
+
+    def subset_from_list(
         self,
-        split: Literal["train", "valid", "test"],
-        task_splits: Optional[dict[str, list[str]]] = None,
+        task_list: list[str],
         benchmark_name_suffix: Optional[str] = "custom",
+        split: Optional[str] = None,
     ):
-        """Create a subset of the benchmark containing only tasks from the specified split.
+        """Create a sub-benchmark containing only the specified tasks.
 
         Args:
-            split: The split to filter for ("train", "valid", or "test")
-            task_splits: Optional dictionary mapping splits to lists of task names.
-                        Example: {"train": ["task1", "task2"], "valid": ["task3", "task4"], "test": ["task5", "task6"]}
-            benchmark_name_suffix: Optional suffix to append to the new benchmark name
+            task_list: List of task names to include in the sub-benchmark.
+            benchmark_name_suffix: Optional suffix to append to the benchmark name. Defaults to "custom".
+            split: Optional split name to append to the benchmark name. Useful for organization.
 
         Returns:
-            A new Benchmark instance containing only tasks from the specified split.
+            Benchmark: A new benchmark instance containing only the specified tasks.
 
         Raises:
-            NotImplementedError: If task_splits is None and the metadata has no 'browsergym_split' column
-            ValueError: If the resulting split would be empty
+            ValueError: If the resulting task list is empty or if any specified task doesn't exist.
         """
-        if task_splits is not None:
-
-            sub_benchmark = Benchmark(
-                name=f"{self.name}_{benchmark_name_suffix}_{split}",
-                high_level_action_set_args=self.high_level_action_set_args,
-                is_multi_tab=self.is_multi_tab,
-                supports_parallel_seeds=self.supports_parallel_seeds,
-                backends=self.backends,
-                env_args_list=[
-                    env_args
-                    for env_args in self.env_args_list
-                    if env_args.task_name in task_splits[split]
-                ],
-                task_metadata=self.task_metadata,
-            )
-        else:
-            split_column = "browsergym_split"
-            # check for a split column in metadata
-            if split_column not in self.task_metadata.columns:
-                raise NotImplementedError(
-                    f"This benchmark does not provide default train/valid/test splits (missing a {repr(split_column)} column in task metadata)"
-                )
+        if not task_list:
+            raise ValueError("Task list cannot be empty")
 
-            # recover the target split
-            sub_benchmark = self.subset_from_regexp(split_column, regexp=f"^{split}$")
-            sub_benchmark.name = f"{self.name}_{split}"
+        # Validate that all requested tasks exist in the original benchmark
+        existing_tasks = {env_args.task_name for env_args in self.env_args_list}
+        invalid_tasks = set(task_list) - existing_tasks
+        if invalid_tasks:
+            raise ValueError(f"The following tasks do not exist in the benchmark: {invalid_tasks}")
 
-        # check that the split exists (non-empty task list)
+        name = f"{self.name}_{benchmark_name_suffix}"
+        if split:
+            name += f"_{split}"
+
+        sub_benchmark = Benchmark(
+            name=name,
+            high_level_action_set_args=self.high_level_action_set_args,
+            is_multi_tab=self.is_multi_tab,
+            supports_parallel_seeds=self.supports_parallel_seeds,
+            backends=self.backends,
+            env_args_list=[
+                env_args for env_args in self.env_args_list if env_args.task_name in task_list
+            ],
+            task_metadata=self.task_metadata,
+        )
+
+        # This check is redundant now due to the validation above, but kept for safety
         if not sub_benchmark.env_args_list:
-            raise ValueError(f"The {split} split for this benchmark is empty.")
+            raise ValueError(
+                f"The custom {split if split else ''} split for this benchmark is empty."
+            )
 
         return sub_benchmark