fix: connection leak, Rice index excludes absences, per-party motion count guard

explorer.py

@@ -258,7 +258,10 @@ def compute_party_discipline(
 
     Rice index per motion per party = fraction of party MPs voting with the party majority.
     The per-party score is the average Rice index across all motions in the date range.
+    Only 'voor' and 'tegen' votes are counted; absent and abstaining MPs are excluded from the
+    Rice index calculation.
     """
+    conn = None
     try:
         conn = duckdb.connect(db_path, read_only=True)
         result = conn.execute(
@@ -272,7 +275,7 @@ def compute_party_discipline(
                 WHERE mp_name LIKE '%,%'
                   AND date >= CAST(? AS DATE)
                   AND date <= CAST(? AS DATE)
-                  AND vote IN ('voor', 'tegen', 'afwezig', 'onthouden')
+                  AND vote IN ('voor', 'tegen')
             ),
             vote_counts AS (
                 SELECT
@@ -313,11 +316,16 @@ def compute_party_discipline(
             """,
             [start_date, end_date],
         ).fetchdf()
-        conn.close()
         return result
     except Exception as exc:
         logger.warning("compute_party_discipline failed: %s", exc)
         return pd.DataFrame(columns=["party", "n_motions", "discipline"])
+    finally:
+        if conn is not None:
+            try:
+                conn.close()
+            except Exception:
+                pass
 
 
 @st.cache_data(show_spinner="Partijposities op SVD-assen laden…")
@@ -955,14 +963,19 @@ def build_compass_tab(db_path: str, window_size: str) -> None:
     disc_df = compute_party_discipline(db_path, start_date, end_date)
 
     st.subheader("Stemgedrag cohesie")
-    if disc_df.empty or disc_df["n_motions"].max() < _MIN_MOTIONS_FOR_DISCIPLINE:
+    if disc_df.empty:
+        st.caption(
+            "Te weinig hoofdelijke stemmingen in dit venster voor een cohesieanalyse."
+        )
+    else:
+        disc_df = disc_df[disc_df["n_motions"] >= _MIN_MOTIONS_FOR_DISCIPLINE].copy()
+        if disc_df.empty:
             st.caption(
                 "Te weinig hoofdelijke stemmingen in dit venster voor een cohesieanalyse."
             )
         else:
             compass_parties = set(df_pos["party"].unique())
             disc_df = disc_df[disc_df["party"].isin(compass_parties)].copy()
-
             if disc_df.empty:
                 st.caption("Geen overlappende partijen tussen kompas en stemmingsdata.")
             else: