Update malariagen_data/anoph/genome_features.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: kunal-10-cloud

malariagen_data/anoph/genome_features.py

@@ -372,6 +372,11 @@ def canonical_transcript(
         # Normalize input: strip whitespace
         gene_normalized = gene.strip()
 
+        # Reject empty identifiers after normalization to avoid ambiguous matches
+        if not gene_normalized:
+            raise ValueError(
+                "Gene identifier is empty after stripping whitespace; please provide a valid gene ID or name."
+            )
         # Try exact ID match first (case-sensitive)
         debug(f"Attempting ID match for '{gene_normalized}'")
         gene_id_match = df_genes[df_genes["ID"].str.strip() == gene_normalized]