Clean up warning capture (#577)

* Clean up warning capture
* Move from DeprecationWarning (dev-focussed) to FutureWarning (user-focussed)

src/calliope/exceptions.py

@@ -9,20 +9,6 @@
 import warnings
 from typing import Optional, Union
 
-# Enable simple format when printing ModelWarnings
-formatwarning_orig = warnings.showwarning
-
-
-def _formatwarning(message, category, filename, lineno, file=None, line=None):
-    """Formats ModelWarnings as "Warning: message" without extra crud"""
-    if category == ModelWarning:
-        return "Warning: " + str(message) + "\n"
-    else:
-        return formatwarning_orig(message, category, filename, lineno, file, line)
-
-
-warnings.showwarning = _formatwarning
-
 
 class ModelError(Exception):
     """
@@ -52,8 +38,12 @@ class BackendWarning(Warning):
     pass
 
 
-def warn(message, _class=ModelWarning):
+def warn(message: str, _class: type[Warning] = ModelWarning):
+    warnings.formatwarning = (
+        lambda message, category, *args, **kwargs: f"{category.__name__}: {message}\n"
+    )
     warnings.warn(message, _class)
+    warnings.formatwarning = warnings._formatwarning_orig
 
 
 def print_warnings_and_raise_errors(

src/calliope/model.py

@@ -10,7 +10,6 @@
 from __future__ import annotations
 
 import logging
-import warnings
 from pathlib import Path
 from typing import TYPE_CHECKING, Callable, Optional, TypeVar, Union
 
@@ -482,10 +481,10 @@ def run(self, force_rerun=False, **kwargs):
         Additional kwargs are passed to the backend.
 
         """
-        warnings.warn(
+        exceptions.warn(
             "`run()` is deprecated and will be removed in a "
             "future version. Use `model.build()` followed by `model.solve()`.",
-            DeprecationWarning,
+            FutureWarning,
         )
         self.build(force=force_rerun)
         self.solve(force=force_rerun)

src/calliope/preprocess/load.py

@@ -152,7 +152,7 @@ def _apply_overrides(
         exceptions.warn(
             "`locations` has been renamed to `nodes` and will stop working "
             "in v0.7.1. Please update your model configuration accordingly.",
-            DeprecationWarning,
+            FutureWarning,
         )
         model_def_copy["nodes"] = model_def_copy["locations"]
         del model_def_copy["locations"]

src/calliope/util/logging.py

@@ -12,6 +12,8 @@
 
 _time_format = "%Y-%m-%d %H:%M:%S"
 
+_orig_py_warning_handlers = logging.getLogger("py.warnings").handlers
+
 
 def setup_root_logger(
     verbosity: str | int, capture_warnings: bool = True
@@ -49,12 +51,15 @@ def setup_root_logger(
     root_logger.addHandler(console)
     root_logger.setLevel(verbosity)
 
+    py_warnings_logger = logging.getLogger("py.warnings")
     if capture_warnings:
         logging.captureWarnings(True)
-        logging.getLogger("py.warnings").setLevel(verbosity)
+        py_warnings_logger.handlers = _orig_py_warning_handlers + [console]
+        py_warnings_logger.setLevel(verbosity)
     else:
         logging.captureWarnings(False)
         logging.getLogger("py.warnings").setLevel("WARNING")
+        py_warnings_logger.handlers = _orig_py_warning_handlers
 
     return root_logger
 

tests/test_core_future_warnings.py

@@ -4,19 +4,19 @@
 from .common.util import check_error_or_warning
 
 
-class TestDeprecationWarnings:
-    def test_run_deprecationwarning(self):
+class TestFutureWarnings:
+    def test_run_futurewarning(self):
         model = build_model(scenario="simple_supply,two_hours,investment_costs")
 
-        with pytest.warns(DeprecationWarning) as warning:
+        with pytest.warns(FutureWarning) as warning:
             model.run()
 
         assert check_error_or_warning(warning, "`run()` is deprecated")
         assert hasattr(model, "backend")
         assert hasattr(model, "results")
 
     def test_locations_instead_of_nodes(self):
-        with pytest.warns(DeprecationWarning) as warning:
+        with pytest.warns(FutureWarning) as warning:
             model = build_model(
                 scenario="simple_supply_locations,one_day,investment_costs"
             )

tests/test_core_util.py

@@ -69,11 +69,19 @@ def test_timing_log(self):
             time_since_solve_start=True,
         )
 
-    @pytest.mark.parametrize(["capture", "expected_level"], [(True, 20), (False, 30)])
-    def test_capture_warnings(self, capture, expected_level):
+    @pytest.mark.parametrize(
+        ["capture", "expected_level", "n_handlers"], [(True, 20, 1), (False, 30, 0)]
+    )
+    def test_capture_warnings(self, capture, expected_level, n_handlers):
         calliope.set_log_verbosity("info", capture_warnings=capture)
 
         assert logging.getLogger("py.warnings").getEffectiveLevel() == expected_level
+        assert len(logging.getLogger("py.warnings").handlers) == n_handlers
+
+    def test_capture_warnings_handlers_dont_append(self):
+        for level in ["critical", "warning", "info", "debug"]:
+            calliope.set_log_verbosity(level, capture_warnings=True)
+            assert len(logging.getLogger("py.warnings").handlers) == 1
 
 
 class TestGenerateRuns: