Handle empty cells in default sheet

src/ert/config/design_matrix.py

@@ -221,14 +221,23 @@ def _read_defaultssheet(
  return {}
  if len(default_df.columns) < 2:
  raise ValueError("Defaults sheet must have at least two columns")
+ empty_cells = [
+ f"Row {default_df.index[i]}, column {default_df.columns[j]}"
+ for i, j in zip(*np.where(pd.isna(default_df)))
+ ]
+ if empty_cells > 0:
+ raise ValueError(f"Default sheet contains empty cells {empty_cells}")
  # Look for initial or trailing whitespace in parameter names. This
  # is disallowed as it can create user confusion and has no use-case.
+ whitespace_errors = []
  for paramname in default_df.loc[:, 0]:
  if paramname != paramname.strip():
- raise ValueError(
+ whitespace_errors.append(
  f"Parameter name '{paramname}' in default values contains "
  "initial or trailing whitespace."
  )
+ if whitespace_errors > 0:
+ raise ValueError(whitespace_errors)
 
  return {row[0]: convert_to_numeric(row[1]) for _, row in default_df.iterrows()}