klippy: Reworked the MCU protocol error message (#5470)

The MCU protocol error message often confuses users, especially after getting bombarded with the config format error line. This PR tries to improve it and has the following goals:

- Put the technical error at the end to prevent confusion and avoid the immediate jump to help channels instead of continuing to read
- Inform the user first what the type of error is (In this case: MCU Protocol error) and not at the end of the long error message
- Give the users a clear instruction what to do (pretty much unchanged), but possibly more approachable because the user is not confused by the technical error anymore
- Shows the version numbers of Klipper separate from all MCU version numbers so that it is more obvious that this is the version of Klipper
- Separates the version numbers between outdated MCUs and up-to-date MCUs, so that it becomes obvious if a MCU flash failed because the MCU doesn't disappear from the outdated list
- Previously, when viewing the errors in a web frontend, additional line breaks made it extremely hard to read the message, sometimes with as little as one word on one line. The error messages are now formatted to not have rogue line breaks, improving readability.

Signed-off-by: Felicia Alexa Hummel <felicia@drachenkatze.org>

klippy/klippy.py

@@ -22,15 +22,17 @@ command to reload the config and restart the host software.
 Printer is halted
 """
 
-message_protocol_error1 = """
-This type of error is frequently caused by running an older
-version of the firmware on the micro-controller (fix by
-recompiling and flashing the firmware).
-"""
+message_protocol_error1 = "MCU Protocol error"
+
 message_protocol_error2 = """
+This is frequently caused by running an older version of the
+firmware on the MCU(s). Fix by recompiling and flashing the
+firmware.
+"""
+
+message_protocol_error3 = """
 Once the underlying issue is corrected, use the "RESTART"
 command to reload the config and restart the host software.
-Protocol error connecting to printer
 """
 
 message_mcu_connect_error = """
@@ -143,15 +145,46 @@ class Printer:
             m.add_printer_objects(config)
         # Validate that there are no undefined parameters in the config file
         pconfig.check_unused_options(config)
-    def _get_versions(self):
-        try:
-            parts = ["%s=%s" % (n.split()[-1], m.get_status()['mcu_version'])
-                     for n, m in self.lookup_objects('mcu')]
-            parts.insert(0, "host=%s" % (self.start_args['software_version'],))
-            return "\nKnown versions: %s\n" % (", ".join(parts),)
-        except:
-            logging.exception("Error in _get_versions()")
-            return ""
+
+    def _build_protocol_error_message(self, e):
+        host_version = self.start_args['software_version']
+
+        msg_update = []
+        msg_updated = []
+
+        for n,mcu_obj in self.lookup_objects('mcu'):
+            try:
+                mcu_version = mcu_obj.get_status()['mcu_version']
+            except:
+                logging.exception("Unable to retrieve mcu_version from mcu_obj")
+                continue
+
+            if mcu_version != host_version:
+                msg_update.append("%s: Current version %s" % (
+                n.split()[-1], mcu_obj.get_status()['mcu_version']))
+            else:
+                msg_updated.append("%s: Current version %s" % (
+                n.split()[-1], mcu_obj.get_status()['mcu_version']))
+
+        if len(msg_updated) == 0:
+            msg_updated.append("<none>")
+
+        version_msg = ["\nYour Klipper version is: %s\n" % host_version,
+               "MCU(s) which should be updated:",
+               "\n%s\n" % "\n".join(msg_update),
+               "Up-to-date MCU(s):",
+               "\n%s\n" % "\n".join(msg_updated)]
+
+        msg = [message_protocol_error1,
+               "",
+               ' '.join(message_protocol_error2.splitlines())[1:],
+               "\n".join(version_msg),
+               ' '.join(message_protocol_error3.splitlines())[1:],
+               "",
+               str(e)]
+
+        return "\n".join(msg)
+
     def _connect(self, eventtime):
         try:
             self._read_config()
@@ -166,9 +199,7 @@ class Printer:
             return
         except msgproto.error as e:
             logging.exception("Protocol error")
-            self._set_state("%s\n%s%s%s" % (str(e), message_protocol_error1,
-                                          self._get_versions(),
-                                          message_protocol_error2))
+            self._set_state(self._build_protocol_error_message(e))
             util.dump_mcu_build()
             return
         except mcu.error as e: