Add --show-locals which prints local variables in tracebacks.

README.rst

@@ -193,7 +193,8 @@ and pytest's many contributors, this project would not have been possible. Thank
 Citation
 --------
 
-If you rely on pytask to manage your research project, please cite it with
+If you rely on pytask to manage your research project, please cite it with the following
+key to help others to discover the tool.
 
 .. code-block::
 

docs/changes.rst

@@ -21,6 +21,7 @@ all releases are available on `PyPI <https://pypi.org/project/pytask>`_ and
 - :gh:`88` adds a ``profile`` command to show information on tasks like duration and
   file size of products.
 - :gh:`93` fixes the display of parametrized arguments in the console.
+- :gh:`94` adds ``--show-locals`` which allows to print local variables in tracebacks.
 
 
 0.0.14 - 2021-03-23

docs/reference_guides/configuration.rst

@@ -130,6 +130,20 @@ The options
         pdb = True
 
 
+.. confval:: show_locals
+
+    If you want to print local variables of each stack frame in the tracebacks, set this
+    value to true.
+
+    .. code-block:: console
+
+        pytask build --show-locals
+
+    .. code-block:: ini
+
+        show_locals = True
+
+
 .. confval:: strict_markers
 
     If you want to raise an error for unregistered markers, pass

docs/tutorials/how_to_debug.rst

@@ -10,6 +10,17 @@ be more productive and gain more confidence in your code.
 To facilitate debugging, pytask offers two command-line options.
 
 
+Tracebacks
+----------
+
+You can enrich the display of tracebacks by show local variables in each stack frame.
+Just execute pytask with
+
+.. code-block:: console
+
+    $ pytask --show-locals
+
+
 Debugging
 ---------
 
@@ -30,7 +41,7 @@ prompt will enter the debugger enabling you to discover the source of the except
 .. tip::
 
     Instead of Python's :mod:`pdb`, use `pdb++ <https://github.com/pdbpp/pdbpp>`_ which
-    is more convenient, colorful has some useful features like the `sticky mode
+    is more convenient, colorful, and has some useful features like the `sticky mode
     <https://github.com/pdbpp/pdbpp#sticky-mode>`_.
 
 

src/_pytask/cli.py

@@ -43,6 +43,7 @@ def pytask_add_hooks(pm):
     from _pytask import collect
     from _pytask import collect_command
     from _pytask import config
+    from _pytask import console
     from _pytask import database
     from _pytask import debugging
     from _pytask import execute
@@ -61,6 +62,7 @@ def pytask_add_hooks(pm):
     pm.register(collect)
     pm.register(collect_command)
     pm.register(config)
+    pm.register(console)
     pm.register(database)
     pm.register(debugging)
     pm.register(execute)

src/_pytask/collect.py

@@ -265,7 +265,7 @@ def pytask_collect_log(session, reports, tasks):
 
             console.print()
 
-            console.print(Traceback.from_exception(*report.exc_info))
+            console.print(Traceback.from_exception(*report.exc_info, show_locals=True))
 
             console.print()
 

src/_pytask/console.py

@@ -3,9 +3,14 @@
 import sys
 from typing import List
 
+import click
+from _pytask.config import hookimpl
+from _pytask.shared import convert_truthy_or_falsy_to_bool
+from _pytask.shared import get_first_non_none_value
 from rich.console import Console
 from rich.tree import Tree
 
+
 _IS_WSL = "IS_WSL" in os.environ or "WSL_DISTRO_NAME" in os.environ
 _IS_WINDOWS_TERMINAL = "WT_SESSION" in os.environ
 _IS_WINDOWS = sys.platform == "win32"
@@ -29,6 +34,28 @@
 console = Console(color_system=_COLOR_SYSTEM)
 
 
+@hookimpl
+def pytask_extend_command_line_interface(cli):
+    show_locals_option = click.Option(
+        ["--show-locals"],
+        is_flag=True,
+        default=None,
+        help="Show local variables in tracebacks.",
+    )
+    cli.commands["build"].params.append(show_locals_option)
+
+
+@hookimpl
+def pytask_parse_config(config, config_from_file, config_from_cli):
+    config["show_locals"] = get_first_non_none_value(
+        config_from_cli,
+        config_from_file,
+        key="show_locals",
+        default=False,
+        callback=convert_truthy_or_falsy_to_bool,
+    )
+
+
 def format_strings_as_flat_tree(strings: List[str], title: str, icon: str) -> str:
     """Format list of strings as flat tree."""
     tree = Tree(title)

src/_pytask/execute.py

@@ -161,6 +161,7 @@ def pytask_execute_task_log_end(report):
 @hookimpl
 def pytask_execute_log_end(session, reports):
     session.execution_end = time.time()
+    show_locals = session.config["show_locals"]
 
     n_successful = sum(report.success for report in reports)
     n_failed = len(reports) - n_successful
@@ -183,7 +184,9 @@ def pytask_execute_log_end(session, reports):
 
             console.print()
 
-            console.print(Traceback.from_exception(*report.exc_info))
+            console.print(
+                Traceback.from_exception(*report.exc_info, show_locals=show_locals)
+            )
 
             console.print()
             show_capture = session.config["show_capture"]

src/_pytask/resolve_dependencies.py

@@ -119,13 +119,16 @@ def _has_node_changed(task_name: str, node_dict):
     try:
         state = node.state()
     except NodeNotFoundError:
-        return True
-    try:
-        state_in_db = State[task_name, node.name].state
-    except orm.ObjectNotFound:
-        return True
-
-    return state != state_in_db
+        out = True
+    else:
+        try:
+            state_in_db = State[task_name, node.name].state
+        except orm.ObjectNotFound:
+            out = True
+        else:
+            out = state != state_in_db
+
+    return out
 
 
 def _check_if_dag_has_cycles(dag):

tests/test_console.py

@@ -0,0 +1,26 @@
+import textwrap
+
+import pytest
+from pytask import cli
+
+
+@pytest.mark.end_to_end
+def test_printing_of_local_variables(tmp_path, runner):
+    source = """
+    def task_dummy():
+        a = 1
+        helper()
+
+    def helper():
+        b = 2
+        raise Exception
+    """
+    tmp_path.joinpath("task_dummy.py").write_text(textwrap.dedent(source))
+
+    result = runner.invoke(cli, [tmp_path.as_posix(), "--show-locals"])
+    assert result.exit_code == 1
+
+    captured = result.output
+    assert " locals " in captured
+    assert "a = 1" in captured
+    assert "b = 2" in captured