No crash on bad plugin provided in configuration file

Raise an error 'bad-plugin-value' instead.
See #4555

ChangeLog

@@ -110,6 +110,11 @@ modules are added.
 
   Closes #585
 
+* Fix a crash when a plugin from the configuration could not be loaded and raise an error
+  'bad-plugin-value' instead
+
+Closes #4555
+
 * Added handling of floating point values when parsing configuration from pyproject.toml
 
   Closes #4518

pylint/lint/pylinter.py

@@ -128,6 +128,11 @@ def _load_reporter_by_class(reporter_class: str) -> type:
         "bad-option-value",
         "Used when a bad value for an inline option is encountered.",
     ),
+    "E0013": (
+        "Plugin '%s' is impossible to load, is it installed ? ('%s')",
+        "bad-plugin-value",
+        "Used when a bad value is used in 'load-plugins'.",
+    ),
 }
 
 
@@ -531,8 +536,11 @@ def load_plugin_modules(self, modnames):
             if modname in self._dynamic_plugins:
                 continue
             self._dynamic_plugins.add(modname)
-            module = astroid.modutils.load_module_from_name(modname)
-            module.register(self)
+            try:
+                module = astroid.modutils.load_module_from_name(modname)
+                module.register(self)
+            except ModuleNotFoundError:
+                pass
 
     def load_plugin_configuration(self):
         """Call the configuration hook for plugins
@@ -542,9 +550,12 @@ def load_plugin_configuration(self):
         settings.
         """
         for modname in self._dynamic_plugins:
-            module = astroid.modutils.load_module_from_name(modname)
-            if hasattr(module, "load_configuration"):
-                module.load_configuration(self)
+            try:
+                module = astroid.modutils.load_module_from_name(modname)
+                if hasattr(module, "load_configuration"):
+                    module.load_configuration(self)
+            except ModuleNotFoundError as e:
+                self.add_message("bad-plugin-value", args=(modname, e), line=0)
 
     def _load_reporters(self) -> None:
         sub_reporters = []

pylint/message/message_handler_mix_in.py

@@ -274,6 +274,17 @@ def add_one_message(
         # update stats
         msg_cat = MSG_TYPES[message_definition.msgid[0]]
         self.msg_status |= MSG_TYPES_STATUS[message_definition.msgid[0]]
+        if self.stats is None:
+            # pylint: disable=fixme
+            # TODO self.stats should make sense,
+            # class should make sense as soon as instantiated
+            # This is not true for Linter and Reporter at least
+            # pylint: enable=fixme
+            self.stats = {
+                msg_cat: 0,
+                "by_module": {self.current_name: {msg_cat: 0}},
+                "by_msg": {},
+            }
         self.stats[msg_cat] += 1
         self.stats["by_module"][self.current_name][msg_cat] += 1
         try:
@@ -291,7 +302,10 @@ def add_one_message(
         else:
             module, obj = get_module_and_frameid(node)
             abspath = node.root().file
-        path = abspath.replace(self.reporter.path_strip_prefix, "", 1)
+        if abspath is not None:
+            path = abspath.replace(self.reporter.path_strip_prefix, "", 1)
+        else:
+            path = "configuration"
         # add the message
         self.reporter.handle_message(
             Message(

pylint/reporters/text.py

@@ -133,10 +133,10 @@ class TextReporter(BaseReporter):
     def __init__(self, output=None):
         BaseReporter.__init__(self, output)
         self._modules = set()
-        self._template = None
+        self._template = self.line_format
 
     def on_set_current_module(self, module, filepath):
-        self._template = str(self.linter.config.msg_template or self.line_format)
+        self._template = str(self.linter.config.msg_template or self._template)
 
     def write_message(self, msg):
         """Convenience method to write a formatted message with class default template"""

tests/functional/p/plugin_does_not_exists.py

@@ -0,0 +1,5 @@
+# pylint: disable=missing-docstring
+
+from shadok import ShadokInteger  # [import-error]
+
+ShadokInteger("Buga ZoMeu")

tests/functional/p/plugin_does_not_exists.rc

@@ -0,0 +1,3 @@
+[master]
+load-plugins=
+    pylint.extensions.check_does_not_exists_in_venv,

tests/functional/p/plugin_does_not_exists.txt

@@ -0,0 +1 @@
+import-error:3:0::Unable to import 'shadok':HIGH