Update generate.py with correct features check

Merge command accidentally included two else statements. Crashing when no primers pass filtering and are written is acceptable behavior because no primers will be outputted anyways.

Author: kbryanhsu

src/qprimer_designer/commands/generate.py

@@ -174,18 +174,9 @@ def run(args):
             features[seq]["forrev"] = "r"
             fout.write(f">{pname}\n{seq}\n")
 
-    features_df = pd.DataFrame(features).T
-    # Original code: crashed with KeyError when no primers passed filtering,
-    # because 'pname' and 'forrev' columns are only added for primers written to output.
-    # if features_df.empty:
-    #     features_df = pd.DataFrame(columns=["pname", "pseq", "forrev", "len", "Tm", "GC", "dG"])
-    # else:
-    #     features_df = features_df.reset_index(names="pseq")[["pname", "pseq", "forrev", "len", "Tm", "GC", "dG"]]
-    #
-    # Fixed: check for 'pname' column presence, not just empty DataFrame.
-    if features_df.empty or "pname" not in features_df.columns:
-        features_df = pd.DataFrame(columns=["pname", "pseq", "forrev", "len", "Tm", "GC", "dG"])
-    else:
+    # Write features CSV
+    if features:
+        features_df = pd.DataFrame(features).T
         features_df = features_df.reset_index(names="pseq")[["pname", "pseq", "forrev", "len", "Tm", "GC", "dG"]]
     else:
         features_df = pd.DataFrame(columns=["pname", "pseq", "forrev", "len", "Tm", "GC", "dG"])