Fix attribute error in log message

Author: melanieclarke

changes/9848.combine_1d.rst

@@ -0,0 +1,2 @@
+Fixed a log message that caused a crashing error in the ``master_background_mos`` step,
+when attempting to combine one or more background spectra with no valid values.

jwst/combine_1d/combine1d.py

@@ -735,10 +735,17 @@ def _read_input_spectra(input_model, exptime_key, input_spectra):
         spectra = input_model.spec
     for in_spec in spectra:
         if not np.any(np.isfinite(in_spec.spec_table.field("flux"))):
-            log.warning(
-                f"Input spectrum {in_spec.source_id} order {in_spec.spectral_order} "
-                f"from group_id {in_spec.meta.group_id} has no valid flux values; skipping."
-            )
+            if in_spec.meta.hasattr("group_id"):
+                msg = (
+                    f"Input spectrum {in_spec.source_id} order {in_spec.spectral_order} "
+                    f"from group_id {in_spec.meta.group_id} has no valid flux values; skipping."
+                )
+            else:
+                msg = (
+                    f"Input spectrum {in_spec.source_id} order {in_spec.spectral_order} "
+                    "has no valid flux values; skipping."
+                )
+            log.warning(msg)
             continue
         spectral_order = in_spec.spectral_order
         if spectral_order not in input_spectra:

jwst/combine_1d/tests/test_combine1d.py

@@ -265,6 +265,28 @@ def test_allnan_skip(wfss_multiexposure, monkeypatch):
     watcher2.assert_seen()
 
 
+def test_allnan_skip_non_wfss(caplog, three_spectra):
+    """Test that all-nan spectra are skipped."""
+    # Set all flux values to NaN
+    for spec in three_spectra.spec:
+        spec.spec_table["FLUX"][:] = np.nan
+
+    result = Combine1dStep.call(three_spectra)
+    assert result.meta.cal_step.combine_1d == "SKIPPED"
+
+    # message when a single spectrum has no valid flux values
+    msg1 = "Input spectrum 0 order 1 has no valid flux values; skipping."
+    assert msg1 in caplog.text
+
+    # message when no valid input spectra are found for the source
+    msg2 = "No valid input spectra found for source. Skipping."
+    assert msg2 in caplog.text
+
+    # message when no valid input spectra at all are found
+    msg3 = "No valid input spectra found in WFSSMultiSpecModel"
+    assert msg2 in caplog.text
+
+
 def test_output_is_not_input(two_spectra):
     """Test that input is not modified."""
     result = Combine1dStep.call(two_spectra)