Do not capture DeprecationWarning and PendingDeprecationWarning by default. (#277)

Author: tobiasraabe

docs/source/changes.md

@@ -8,6 +8,9 @@ releases are available on [PyPI](https://pypi.org/project/pytask) and
 ## 0.2.3 - 2022-xx-xx
 
 - {pull}`276` fixes `pytask clean` when git is not installed. Fixes {issue}`275`.
+- {pull}`277` ignores `DeprecationWarning` and `PendingDeprecationWarning` by default.
+  Previously, they were enabled, but they should be shown when testing the project with
+  pytest, not after the execution with pytask. Fixes {issue}`269`.
 
 ## 0.2.2 - 2022-05-14
 

docs/source/how_to_guides/capture_warnings.md

@@ -78,28 +78,6 @@ configured by the `filterwarnings` configuration option.
 Although not recommended, you can use the `--disable-warnings` command-line option to
 suppress the warning summary entirely from the test run output.
 
-## `DeprecationWarning` and `PendingDeprecationWarning`
-
-By default pytask will display `DeprecationWarning` and `PendingDeprecationWarning`
-warnings from user code and third-party libraries. This helps users keep their code
-modern and avoid breakages when deprecated warnings are effectively removed.
-
-Sometimes it is useful to hide some specific deprecation warnings that happen in code
-that you have no control over (such as third-party libraries), in which case you might
-use the warning filters options (ini or marks) to ignore those warnings.
-
-For example:
-
-```toml
-[tool.pytask.ini_options]
-filterwarnings  = [
-    "ignore:.*U.*mode is deprecated:DeprecationWarning"
-]
-```
-
-This will ignore all warnings of type `DeprecationWarning` where the start of the
-message matches the regular expression `".*U.*mode is deprecated"`.
-
 ## Debugging warnings
 
 Sometimes it is not clear which line of code triggered a warning. To find the location,

src/_pytask/collect_command.py

@@ -126,8 +126,8 @@ def _find_common_ancestor_of_all_nodes(
     for task in tasks:
         all_paths.append(task.path)
         if show_nodes:
-            all_paths.extend(map(lambda x: x.path, tree_just_flatten(task.depends_on)))
-            all_paths.extend(map(lambda x: x.path, tree_just_flatten(task.produces)))
+            all_paths.extend(x.path for x in tree_just_flatten(task.depends_on))
+            all_paths.extend(x.path for x in tree_just_flatten(task.produces))
 
     common_ancestor = find_common_ancestor(*all_paths, *paths)
 

src/_pytask/warnings.py

@@ -3,7 +3,6 @@
 
 import functools
 import re
-import sys
 import textwrap
 import warnings
 from collections import defaultdict
@@ -90,12 +89,6 @@ def catch_warnings_for_item(
         # mypy can't infer that record=True means log is not None; help it.
         assert log is not None
 
-        if not sys.warnoptions:
-            # If user is not explicitly configuring warning filters, show deprecation
-            # warnings by default (#2908).
-            warnings.filterwarnings("always", category=DeprecationWarning)
-            warnings.filterwarnings("always", category=PendingDeprecationWarning)
-
         for arg in session.config["filterwarnings"]:
             warnings.filterwarnings(*parse_warning_filter(arg, escape=False))
 

tests/test_warnings.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import subprocess
 import textwrap
 
 import pytest
@@ -119,3 +120,38 @@ def task_example():
     assert result.exit_code == ExitCode.OK
     assert ("Warnings" in result.output) is not add_config
     assert ("warning!!!" in result.output) is not add_config
+
+
+@pytest.mark.parametrize("warning", ["DeprecationWarning", "PendingDeprecationWarning"])
+def test_deprecation_warnings_are_not_captured(tmp_path, warning):
+    path_to_warn_module = tmp_path.joinpath("warning.py")
+    source = """
+    import importlib.util
+    import sys
+    from pathlib import Path
+
+    def task_example():
+        spec = importlib.util.spec_from_file_location(
+            "warning", Path(__file__).parent / "warning.py"
+        )
+        warning_module = importlib.util.module_from_spec(spec)
+        sys.modules["warning"] = warning_module
+        spec.loader.exec_module(warning_module)
+        warning_module.warn_now()
+    """
+    tmp_path.joinpath("task_example.py").write_text(textwrap.dedent(source))
+
+    warn_module = f"""
+    import warnings
+
+    def warn_now():
+        warnings.warn("warning!!!", {warning})
+    """
+    path_to_warn_module.write_text(textwrap.dedent(warn_module))
+
+    # Cannot use runner since then warnings are not ignored by default.
+    result = subprocess.run(("pytask"), cwd=tmp_path, capture_output=True)
+
+    assert result.returncode == ExitCode.OK
+    assert "Warnings" not in result.stdout.decode()
+    assert "warning!!!" not in result.stdout.decode()