From 81ca3676b025ed27987a1b8a6a875ea2e125bf93 Mon Sep 17 00:00:00 2001
From: Jason Kai <21226986+kaitj@users.noreply.github.com>
Date: Mon, 6 Apr 2026 10:05:56 -0400
Subject: [PATCH] Remove ambiguity for polars filter

Calls on `implode` to turn pl.Series to a flattened list to remove ambiguity regarding how the matching should be performed (row-wise vs column-wise).
`is_in` now operates by performing column-wise matching.
---
 src/rbc/bids/session.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/rbc/bids/session.py b/src/rbc/bids/session.py
index 7760f602..aa5ebefb 100644
--- a/src/rbc/bids/session.py
+++ b/src/rbc/bids/session.py
@@ -65,7 +65,7 @@ def _resolve_anat(
 ) -> pl.DataFrame:
     """Resolve the anat subset for a given primary group."""
     if runs_correspond:
-        run_vals = primary_group["run"].drop_nulls().unique()
+        run_vals = primary_group["run"].drop_nulls().unique().implode()
         matched = anat.filter(pl.col("run").is_in(run_vals))
         return matched if not matched.is_empty() else fallback_anat
     return fallback_anat