Better exceptions with tryceratops.

.pre-commit-config.yaml

@@ -90,6 +90,11 @@ repos:
     rev: "0.46"
     hooks:
     -   id: check-manifest
+-   repo: https://github.com/guilatrova/tryceratops
+    rev: v0.6.0
+    hooks:
+    -   id: tryceratops
+        exclude: (console\.py|test_mark_expression\.py)
 -   repo: meta
     hooks:
     -   id: check-hooks-apply

docs/source/changes.rst

@@ -12,6 +12,8 @@ all releases are available on `PyPI <https://pypi.org/project/pytask>`_ and
 
 - :gh:`142` removes the display of skipped and persisted tasks from the live execution
   table for the default verbosity level of 1. They are displayed at 2.
+- :gh:`144` adds tryceratops to the pre-commit hooks for catching issues with
+  exceptions.
 
 
 0.1.1 - 2021-08-25

pyproject.toml

@@ -4,3 +4,7 @@ requires = ["setuptools>=45", "wheel", "setuptools_scm[toml]>=6.0"]
 
 [tool.setuptools_scm]
 write_to = "src/_pytask/_version.py"
+
+
+[tool.tryceratops]
+ignore = ["TC003"]

src/_pytask/collect.py

@@ -192,7 +192,7 @@ def pytask_collect_node(session, path, node):
         ):
             case_sensitive_path = find_case_sensitive_path(node, "win32")
             if str(node) != str(case_sensitive_path):
-                raise Exception(_TEMPLATE_ERROR.format(node, case_sensitive_path))
+                raise ValueError(_TEMPLATE_ERROR.format(node, case_sensitive_path))
 
         return FilePathNode.from_path(node)
 

src/_pytask/config.py

@@ -229,7 +229,7 @@ def _find_project_root_and_ini(paths: List[Path]):
         if path.exists():
             try:
                 _read_config(path)
-            except Exception:
+            except KeyError:
                 pass
             else:
                 config_path = path

src/_pytask/debugging.py

@@ -7,6 +7,7 @@
 from _pytask.config import hookimpl
 from _pytask.console import console
 from _pytask.nodes import PythonFunctionTask
+from _pytask.outcomes import Exit
 from _pytask.shared import convert_truthy_or_falsy_to_bool
 from _pytask.shared import get_first_non_none_value
 from _pytask.traceback import remove_internal_traceback_frames_from_exc_info
@@ -238,7 +239,7 @@ def do_quit(self, arg):
                 ret = super().do_quit(arg)
 
                 if cls._recursive_debug == 0:
-                    raise Exception("Quitting debugger")
+                    raise Exit("Quitting debugger")
 
                 return ret
 
@@ -341,7 +342,7 @@ def wrapper(*args, **kwargs):
         try:
             task_function(*args, **kwargs)
 
-        except Exception as e:
+        except Exception:
             # Order is important! Pausing the live object before the capturemanager
             # would flush the table to stdout and it will be visible in the captured
             # output.
@@ -371,7 +372,7 @@ def wrapper(*args, **kwargs):
             live_manager.resume()
             capman.resume()
 
-            raise e
+            raise
 
     task.function = wrapper
 
@@ -432,4 +433,4 @@ def post_mortem(t) -> None:
     p.reset()
     p.interaction(None, t)
     if p.quitting:
-        raise Exception("Quitting debugger")
+        raise Exit("Quitting debugger")

src/_pytask/execute.py

@@ -12,10 +12,12 @@
 from _pytask.exceptions import NodeNotFoundError
 from _pytask.mark import Mark
 from _pytask.nodes import FilePathNode
+from _pytask.outcomes import Exit
 from _pytask.outcomes import Persisted
 from _pytask.outcomes import Skipped
 from _pytask.report import ExecutionReport
 from _pytask.shared import reduce_node_name
+from _pytask.traceback import format_exception_without_traceback
 from _pytask.traceback import remove_traceback_from_exc_info
 from _pytask.traceback import render_exc_info
 
@@ -96,10 +98,10 @@ def pytask_execute_task_setup(session, task):
         node = session.dag.nodes[dependency]["node"]
         try:
             node.state()
-        except NodeNotFoundError:
+        except NodeNotFoundError as e:
             raise NodeNotFoundError(
                 f"{node.name} is missing and required for {task.name}."
-            )
+            ) from e
 
     # Create directory for product if it does not exist. Maybe this should be a `setup`
     # method for the node classes.
@@ -122,8 +124,10 @@ def pytask_execute_task_teardown(session, task):
         node = session.dag.nodes[product]["node"]
         try:
             node.state()
-        except NodeNotFoundError:
-            raise NodeNotFoundError(f"{node.name} was not produced by {task.name}.")
+        except NodeNotFoundError as e:
+            raise NodeNotFoundError(
+                f"{node.name} was not produced by {task.name}."
+            ) from e
 
 
 @hookimpl(trylast=True)
@@ -156,6 +160,9 @@ def pytask_execute_task_process_report(session, report):
         if session.n_tasks_failed >= session.config["max_failures"]:
             session.should_stop = True
 
+        if report.exc_info and isinstance(report.exc_info[1], Exit):
+            session.should_stop = True
+
     return True
 
 
@@ -198,7 +205,10 @@ def pytask_execute_log_end(session, reports):
 
             console.print()
 
-            console.print(render_exc_info(*report.exc_info, show_locals))
+            if report.exc_info and isinstance(report.exc_info[1], Exit):
+                console.print(format_exception_without_traceback(report.exc_info))
+            else:
+                console.print(render_exc_info(*report.exc_info, show_locals))
 
             console.print()
             show_capture = session.config["show_capture"]

src/_pytask/outcomes.py

@@ -1,3 +1,6 @@
+from typing import Optional
+
+
 class PytaskOutcome(Exception):
     """Base outcome of a task."""
 
@@ -16,3 +19,14 @@ class SkippedUnchanged(PytaskOutcome):
 
 class Persisted(PytaskOutcome):
     """Outcome if task should persist."""
+
+
+class Exit(Exception):
+    """Raised for immediate program exits (no tracebacks/summaries)."""
+
+    def __init__(
+        self, msg: str = "unknown reason", returncode: Optional[int] = None
+    ) -> None:
+        self.msg = msg
+        self.returncode = returncode
+        super().__init__(msg)

src/_pytask/traceback.py

@@ -21,6 +21,11 @@ def render_exc_info(exc_type, exc_value, traceback, show_locals=False):
     return renderable
 
 
+def format_exception_without_traceback(exc_info):
+    """Format an exception without displaying the traceback."""
+    return f"[red bold]{exc_info[0].__name__}:[/] {exc_info[1]}"
+
+
 def remove_traceback_from_exc_info(exc_info):
     """Remove traceback from exception."""
     return (*exc_info[:2], None)

tests/test_config.py

@@ -1,8 +1,10 @@
 import os
 import textwrap
+from contextlib import ExitStack as does_not_raise  # noqa: N813
 
 import pytest
 from _pytask.config import _find_project_root_and_ini
+from _pytask.config import _read_config
 from pytask import main
 
 
@@ -131,3 +133,22 @@ def test_passing_paths_via_configuration_file(tmp_path, config_path, file_or_fol
 
     assert session.exit_code == 0
     assert len(session.tasks) == 1
+
+
+@pytest.mark.unit
+@pytest.mark.parametrize(
+    "file_exists, content, expectation, expected",
+    [
+        (False, None, pytest.raises(KeyError), None),
+        (True, "[pytask]", does_not_raise(), {}),
+        (True, "[pytask]\nvalue = 1", does_not_raise(), {"value": "1"}),
+    ],
+)
+def test_read_config(tmp_path, file_exists, content, expectation, expected):
+    path = tmp_path / "config.ini"
+    if file_exists:
+        path.write_text(content)
+
+    with expectation:
+        result = _read_config(path)
+        assert result == expected