mcu: Generate a dummy response to query commands when in debugging mode

Previously a querycmd.send() request would silently hang if the code
is run in "file output" mode (that is, it is not communicating with a
real micro-controller).  This behavior makes it hard to implement
regression tests and is generally confusing.

Change the code to respond with a dummy response (typically all zeros
and empty strings) instead.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/extras/ads1220.py

@@ -175,6 +175,8 @@ class ADS1220:
         # read startup register state and validate
         val = self.read_reg(0x0, 4)
         if val != RESET_STATE:
+            if self.mcu.is_fileoutput():
+                return
             raise self.printer.command_error(
                 "Invalid ads1220 reset state (got %s vs %s).\n"
                 "This is generally indicative of connection problems\n"
@@ -209,6 +211,8 @@ class ADS1220:
         self.spi.spi_send(write_command)
         stored_val = self.read_reg(reg, len(register_bytes))
         if bytearray(register_bytes) != stored_val:
+            if self.mcu.is_fileoutput():
+                return
             raise self.printer.command_error(
                 "Failed to set ADS1220 register [0x%x] to %s: got %s. "
                 "This may be a connection problem (e.g. faulty wiring)" % (

klippy/mcu.py

@@ -22,6 +22,20 @@ MAX_NOMINAL_DURATION = 3.0
 # Command transmit helper classes
 ######################################################################
 
+# Generate a dummy response to query commands when in debugging mode
+class DummyResponse:
+    def __init__(self, serial, name, oid=None):
+        params = {}
+        if oid is not None:
+            params['oid'] = oid
+        msgparser = serial.get_msgparser()
+        resp = msgparser.create_dummy_response(name, params)
+        resp['#sent_time'] = 0.
+        resp['#receive_time'] = 0.
+        self._response = resp
+    def get_response(self, cmds, cmd_queue, minclock=0, reqclock=0, retry=True):
+        return dict(self._response)
+
 # Class to retry sending of a query command until a given response is received
 class RetryAsyncCommand:
     TIMEOUT_TIME = 5.0
@@ -69,7 +83,9 @@ class CommandQueryWrapper:
         self._oid = oid
         self._error = conn_helper.get_mcu().get_printer().command_error
         self._xmit_helper = serialhdl.SerialRetryCommand
-        if is_async:
+        if conn_helper.get_mcu().is_fileoutput():
+            self._xmit_helper = DummyResponse
+        elif is_async:
             self._xmit_helper = RetryAsyncCommand
         if cmd_queue is None:
             cmd_queue = serial.get_default_command_queue()

klippy/msgproto.py

@@ -353,6 +353,27 @@ class MessageParser:
             #logging.exception("Unable to encode")
             self._error("Unable to encode: %s", msgname)
         return cmd
+    def create_dummy_response(self, msgname, params={}):
+        mp = self.messages_by_name.get(msgname)
+        if mp is None:
+            self._error("Unknown response: %s", msgname)
+        argparts = dict(params)
+        for name, t in mp.name_to_type.items():
+            if name not in argparts:
+                tval = 0
+                if t.is_dynamic_string:
+                    tval = ()
+                argparts[name] = tval
+        try:
+            msg = mp.encode_by_name(**argparts)
+        except error as e:
+            raise
+        except:
+            #logging.exception("Unable to encode")
+            self._error("Unable to encode: %s", msgname)
+        res, pos = mp.parse(msg, 0)
+        res['#name'] = msgname
+        return res
     def fill_enumerations(self, enumerations):
         for add_name, add_enums in enumerations.items():
             enums = self.enumerations.setdefault(add_name, {})