Change experiment exists from fail to skip-with-warning

- Rename check_safe_to_run to should_skip_experiment
- Return bool and print warning instead of raising FileExistsError
- Allows chained experiment commands to continue when some already exist
- --force flag still available for intentional overwrites

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: dariocazzani

experiments/paths.py

@@ -85,18 +85,18 @@ def experiment_exists(experiment_dir: Path) -> bool:
     return (experiment_dir / "results.json").exists()
 
 
-def check_safe_to_run(experiment_dir: Path, *, force: bool = False) -> None:
-    """Check if it's safe to run an experiment.
+def should_skip_experiment(experiment_dir: Path, *, force: bool = False) -> bool:
+    """Check if an experiment should be skipped.
 
     Args:
         experiment_dir: Path to experiment directory.
         force: If True, allow overwriting existing results.
 
-    Raises:
-        FileExistsError: If experiment exists and force is False.
+    Returns:
+        True if the experiment should be skipped (already exists and not forcing).
     """
     if experiment_exists(experiment_dir) and not force:
-        raise FileExistsError(
-            f"Experiment already exists: {experiment_dir}\n"
-            f"Use --force to overwrite, or check if this is a duplicate run."
-        )
+        print(f"\n[SKIP] Experiment already exists: {experiment_dir}")
+        print("       Use --force to overwrite.\n")
+        return True
+    return False

experiments/train.py

@@ -26,7 +26,7 @@
 )
 from experiments.datasets.factory import AUGMENT_CHOICES, get_dataset
 from experiments.models.factory import get_model
-from experiments.paths import check_safe_to_run
+from experiments.paths import should_skip_experiment
 from experiments.training import checkpoint, logging_config
 from experiments.training.loops import evaluate, get_scheduler, train_epoch
 
@@ -199,8 +199,9 @@ def main() -> None:
         quiet=args.quiet,
     )
 
-    # Safety check: prevent accidental overwrites
-    check_safe_to_run(Path(config.output_dir), force=args.force)
+    # Skip if experiment already exists (unless --force)
+    if should_skip_experiment(Path(config.output_dir), force=args.force):
+        return
 
     train(config)
 

experiments/train_kd.py

@@ -25,7 +25,7 @@
 )
 from experiments.datasets.factory import AUGMENT_CHOICES, get_dataset
 from experiments.models.factory import get_model
-from experiments.paths import ExperimentType, check_safe_to_run, get_experiment_dir
+from experiments.paths import ExperimentType, get_experiment_dir, should_skip_experiment
 from experiments.training import checkpoint, logging_config
 from experiments.training.kd_loss import KDLoss
 from experiments.training.loops import evaluate, get_scheduler
@@ -253,8 +253,9 @@ def main() -> None:
         )
         args.output_dir = str(experiment_dir)
 
-    # Safety check: prevent accidental overwrites
-    check_safe_to_run(Path(args.output_dir), force=args.force)
+    # Skip if experiment already exists (unless --force)
+    if should_skip_experiment(Path(args.output_dir), force=args.force):
+        return
 
     config = TrainConfig(
         model=args.model,