Fix bug where template file was interpreted as parameters file

src/ert/config/ert_config.py

@@ -408,12 +408,6 @@ def _validate_dict(
     ) -> List[Union[ErrorInfo, ConfigValidationError]]:
         errors = []
 
-        gen_kws = config_dict.get("GEN_KW", [])
-        for gen_kw in gen_kws:
-            file_path = Path(gen_kw[1])
-            if file_path.stat().st_size == 0:
-                raise ConfigValidationError(f"No parameters specified in {file_path}")
-
         if ConfigKeys.SUMMARY in config_dict and ConfigKeys.ECLBASE not in config_dict:
             errors.append(
                 ErrorInfo(

src/ert/config/gen_kw_config.py

@@ -105,12 +105,13 @@ def from_config_list(cls, gen_kw: List[str]) -> Self:
 
         if len(positional_args) == 2:
             parameter_file = _get_abs_path(positional_args[1])
+            parameter_file_context = positional_args[1]
             template_file = None
             output_file = None
         elif len(positional_args) == 4:
             output_file = positional_args[2]
             parameter_file = _get_abs_path(positional_args[3])
-
+            parameter_file_context = positional_args[3]
             template_file = _get_abs_path(positional_args[1])
             if not os.path.isfile(template_file):
                 errors.append(
@@ -125,7 +126,14 @@ def from_config_list(cls, gen_kw: List[str]) -> Self:
         if not os.path.isfile(parameter_file):
             errors.append(
                 ConfigValidationError.with_context(
-                    f"No such parameter file: {parameter_file}", positional_args[3]
+                    f"No such parameter file: {parameter_file}", parameter_file_context
+                )
+            )
+        elif Path(parameter_file).stat().st_size == 0:
+            errors.append(
+                ConfigValidationError.with_context(
+                    f"No parameters specified in {parameter_file}",
+                    parameter_file_context,
                 )
             )
 

tests/unit_tests/config/test_ensemble_config.py

@@ -112,7 +112,7 @@ def test_that_files_for_refcase_exists(existing_suffix, expected_suffix):
 @pytest.mark.usefixtures("use_tmpdir")
 def test_ensemble_config_duplicate_node_names():
     duplicate_name = "Test_name"
-    Path("MULTFLT.TXT").write_text("", encoding="utf-8")
+    Path("MULTFLT.TXT").write_text("a UNIFORM 0 1", encoding="utf-8")
     Path("FAULT_TEMPLATE").write_text("", encoding="utf-8")
     config_dict = {
         ConfigKeys.GEN_DATA: [

tests/unit_tests/config/test_ert_config.py

@@ -1618,12 +1618,15 @@ def test_using_relative_path_to_eclbase_sets_jobname_to_basename(tmp_path):
     )
 
 
-def test_that_empty_params_file_gives_reasonable_error(tmpdir):
+@pytest.mark.parametrize(
+    "param_config", ["coeffs_priors", "template.txt output.txt coeffs_priors"]
+)
+def test_that_empty_params_file_gives_reasonable_error(tmpdir, param_config):
     with tmpdir.as_cwd():
         config = """
         NUM_REALIZATIONS 1
-        GEN_KW COEFFS coeffs_priors
-        """
+        GEN_KW COEFFS """
+        config += param_config
 
         with open("config.ert", mode="w", encoding="utf-8") as fh:
             fh.writelines(config)
@@ -1632,5 +1635,9 @@ def test_that_empty_params_file_gives_reasonable_error(tmpdir):
         with open("coeffs_priors", mode="w", encoding="utf-8") as fh:
             pass
 
+        # Create an empty file named 'template.txt'
+        with open("template.txt", mode="w", encoding="utf-8") as fh:
+            pass
+
         with pytest.raises(ConfigValidationError, match="No parameters specified in"):
             ErtConfig.from_file("config.ert")