Better info on no profiles to import for gcode

CIRA-4946

If a gcode is sliced with default profiles, there won't be any custom
profiles to import from that gcode. In that case, we show a info message
telling the user about this instead of showing an error message.

cura/ProfileReader.py

@@ -3,6 +3,13 @@
 
 from UM.PluginObject import PluginObject
 
+
+# Exception when there is no profile to import from a given files.
+# Note that this should not be treated as an exception but as an information instead.
+class NoProfileException(Exception):
+    pass
+
+
 ##  A type of plug-ins that reads profiles from a file.
 #
 #   The profile is then stored as instance container of the type user profile.
@@ -14,4 +21,4 @@ class ProfileReader(PluginObject):
     #
     #   \return \type{Profile|Profile[]} The profile that was obtained from the file or a list of Profiles.
     def read(self, file_name):
-        raise NotImplementedError("Profile reader plug-in was not correctly implemented. The read function was not implemented.")
+        raise NotImplementedError("Profile reader plug-in was not correctly implemented. The read function was not implemented.")

cura/Settings/CuraContainerRegistry.py

@@ -29,6 +29,7 @@ from .ExtruderManager import ExtruderManager
 
 from cura.CuraApplication import CuraApplication
 from cura.Machines.QualityManager import getMachineDefinitionIDForQualitySearch
+from cura.ProfileReader import NoProfileException
 
 from UM.i18n import i18nCatalog
 catalog = i18nCatalog("cura")
@@ -185,6 +186,8 @@ class CuraContainerRegistry(ContainerRegistry):
             profile_reader = plugin_registry.getPluginObject(plugin_id)
             try:
                 profile_or_list = profile_reader.read(file_name)  # Try to open the file with the profile reader.
+            except NoProfileException:
+                return { "status": "ok", "message": catalog.i18nc("@info:status Don't translate the XML tags <filename> or <message>!", "No custom profile to import in file <filename>{0}</filename>", file_name)}
             except Exception as e:
                 # Note that this will fail quickly. That is, if any profile reader throws an exception, it will stop reading. It will only continue reading if the reader returned None.
                 Logger.log("e", "Failed to import profile from %s: %s while using profile reader. Got exception %s", file_name,profile_reader.getPluginId(), str(e))

plugins/GCodeProfileReader/GCodeProfileReader.py

@@ -9,7 +9,7 @@ from UM.Logger import Logger
 from UM.i18n import i18nCatalog
 catalog = i18nCatalog("cura")
 
-from cura.ProfileReader import ProfileReader
+from cura.ProfileReader import ProfileReader, NoProfileException
 
 ##  A class that reads profile data from g-code files.
 #
@@ -66,6 +66,11 @@ class GCodeProfileReader(ProfileReader):
             return None
 
         serialized = unescapeGcodeComment(serialized)
+        serialized = serialized.strip()
+
+        if not serialized:
+            Logger.log("i", "No custom profile to import from this g-code: %s", file_name)
+            raise NoProfileException()
 
         # serialized data can be invalid JSON
         try: