CLI: Fix verdi plugin list incorrectly not displaying description (#…

…6411)

The implementation would call `get_description` on the plugin to retrieve
a verbose description and would catch the `AttributeError` in case the
method was not defined. However, the conditional determining whether the
plugin is a process or process function was flawed and it would always
call `plugin.is_process_function` for plugins that were not processes.
This would therefore raise an `AttributeError` for any other plugins
besides process functions and so the command would always print that no
additional information was available.

src/aiida/cmdline/commands/cmd_plugin.py

@@ -48,7 +48,9 @@ def plugin_list(entry_point_group, entry_point):
             echo.echo_critical(str(exception))
         else:
             try:
-                if (inspect.isclass(plugin) and issubclass(plugin, Process)) or plugin.is_process_function:
+                if (inspect.isclass(plugin) and issubclass(plugin, Process)) or (
+                    hasattr(plugin, 'is_process_function') and plugin.is_process_function
+                ):
                     print_process_info(plugin)
                 else:
                     echo.echo(str(plugin.get_description()))

tests/cmdline/commands/test_plugin.py

@@ -10,7 +10,8 @@
 
 import pytest
 from aiida.cmdline.commands import cmd_plugin
-from aiida.plugins import CalculationFactory, WorkflowFactory
+from aiida.parsers import Parser
+from aiida.plugins import CalculationFactory, ParserFactory, WorkflowFactory
 from aiida.plugins.entry_point import ENTRY_POINT_GROUP_TO_MODULE_PATH_MAP
 
 
@@ -56,3 +57,19 @@ def test_plugin_list_detail(run_cli_command, entry_point_string):
 
     result = run_cli_command(cmd_plugin.plugin_list, [entry_point_group, entry_point_name])
     assert entry_point.__doc__ in result.output
+
+
+class CustomParser(Parser):
+    @classmethod
+    def get_description(cls) -> str:
+        return 'str69'
+
+
+def test_plugin_description(run_cli_command, entry_points):
+    """Test that ``verdi plugin list`` uses ``get_description`` if defined."""
+
+    entry_points.add(CustomParser, 'aiida.parsers:custom.parser')
+    assert ParserFactory('custom.parser') is CustomParser
+
+    result = run_cli_command(cmd_plugin.plugin_list, ['aiida.parsers', 'custom.parser'])
+    assert result.output.strip() == 'str69'