Don't display a table when no entry is present.

docs/source/changes.rst

@@ -14,6 +14,7 @@ all releases are available on `PyPI <https://pypi.org/project/pytask>`_ and
 - :gh:`187` allows to enable and disable showing tracebacks and potentially different
   styles in the future with :confval:`show_traceback=True|False`.
 - :gh:`188` refactors some code related to :class:`_pytask.enums.ExitCode`.
+- :gh:`189` do not display a table in the execution if no task was run.
 
 
 0.1.4 - 2022-01-04

src/_pytask/live.py

@@ -156,7 +156,9 @@ def pytask_execute_build(self) -> Generator[None, None, None]:
         self._live_manager.start()
         yield
         self._live_manager.stop(transient=True)
-        console.print(self._generate_table(reduce_table=False, sort_table=True))
+        table = self._generate_table(reduce_table=False, sort_table=True)
+        if table is not None:
+            console.print(table)
 
     @hookimpl(tryfirst=True)
     def pytask_execute_task_log_start(self, task: MetaTask) -> bool:
@@ -179,53 +181,53 @@ def _generate_table(self, reduce_table: bool, sort_table: bool) -> Optional[Tabl
         if more entries are requested, the list is filled up with completed tasks.
 
         """
-        if self._running_tasks or self._reports:
-
-            n_reports_to_display = self._n_entries_in_table - len(self._running_tasks)
-            if not reduce_table:
-                relevant_reports = self._reports
-            elif n_reports_to_display >= 1:
-                relevant_reports = self._reports[-n_reports_to_display:]
-            else:
-                relevant_reports = []
-
-            if sort_table:
-                relevant_reports = sorted(
-                    relevant_reports, key=lambda report: report["name"]
+        n_reports_to_display = self._n_entries_in_table - len(self._running_tasks)
+        if not reduce_table:
+            relevant_reports = self._reports
+        elif n_reports_to_display >= 1:
+            relevant_reports = self._reports[-n_reports_to_display:]
+        else:
+            relevant_reports = []
+
+        if sort_table:
+            relevant_reports = sorted(
+                relevant_reports, key=lambda report: report["name"]
+            )
+
+        table = Table()
+        table.add_column("Task", overflow="fold")
+        table.add_column("Outcome")
+        for report in relevant_reports:
+            if (
+                report["outcome"]
+                in (
+                    TaskOutcome.SKIP,
+                    TaskOutcome.SKIP_UNCHANGED,
+                    TaskOutcome.SKIP_PREVIOUS_FAILED,
+                    TaskOutcome.PERSISTENCE,
                 )
-
-            table = Table()
-            table.add_column("Task", overflow="fold")
-            table.add_column("Outcome")
-            for report in relevant_reports:
-                if (
-                    report["outcome"]
-                    in (
-                        TaskOutcome.SKIP,
-                        TaskOutcome.SKIP_UNCHANGED,
-                        TaskOutcome.SKIP_PREVIOUS_FAILED,
-                        TaskOutcome.PERSISTENCE,
-                    )
-                    and self._verbose < 2
-                ):
-                    pass
-                else:
-                    table.add_row(
-                        format_task_id(
-                            report["task"],
-                            editor_url_scheme=self._editor_url_scheme,
-                            short_name=True,
-                        ),
-                        Text(report["outcome"].symbol, style=report["outcome"].style),
-                    )
-            for task in self._running_tasks.values():
+                and self._verbose < 2
+            ):
+                pass
+            else:
                 table.add_row(
                     format_task_id(
-                        task, editor_url_scheme=self._editor_url_scheme, short_name=True
+                        report["task"],
+                        editor_url_scheme=self._editor_url_scheme,
+                        short_name=True,
                     ),
-                    "running",
+                    Text(report["outcome"].symbol, style=report["outcome"].style),
                 )
-        else:
+        for task in self._running_tasks.values():
+            table.add_row(
+                format_task_id(
+                    task, editor_url_scheme=self._editor_url_scheme, short_name=True
+                ),
+                "running",
+            )
+
+        # If the table is empty, do not display anything.
+        if table.rows == []:
             table = None
 
         return table

tests/test_live.py

@@ -131,18 +131,22 @@ def test_live_execution_displays_skips_and_persists(capsys, tmp_path, verbose, o
 
     # Test final table with reported outcome.
     captured = capsys.readouterr()
-    assert "Task" in captured.out
-    assert "Outcome" in captured.out
 
     if verbose < 2 and outcome in (
         TaskOutcome.SKIP,
         TaskOutcome.SKIP_UNCHANGED,
         TaskOutcome.SKIP_PREVIOUS_FAILED,
         TaskOutcome.PERSISTENCE,
     ):
+        # An empty table is not shown.
+        assert "Task" not in captured.out
+        assert "Outcome" not in captured.out
+
         assert "task_module.py::task_example" not in captured.out
         assert f"│ {outcome.symbol}" not in captured.out
     else:
+        assert "Task" in captured.out
+        assert "Outcome" in captured.out
         assert "task_module.py::task_example" in captured.out
         assert f"│ {outcome.symbol}" in captured.out