MAINT: refactor _Messages class

Summary

For caosdb-server#286 (closed)

• rename _Messages to Messages since it is public API
• change parent class to list since Multiple Messages with same type and code may occur
• deprecate lots of stuff that makes usage fuzzy (e.g. three different ways to supply arguments) and concentrate on behavior that is close to that of lists (which is what users know)

Focus

It is quite hard to figure out what the current behavior is. However, I preserved it for now and added lots of deprecation warnings.

Test Environment

unit and int test

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• All automated tests pass
• Reference related issues
• Up-to-date CHANGELOG.md (or not necessary)
• Up-to-date JSON schema (or not necessary)
• Appropriate user and developer documentation (or not necessary)
  • How do I use the software? Assume "stupid" users.
  • How do I develop or debug the software? Assume novice developers.
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
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Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• Up-to-date CHANGELOG.md (or not necessary)
• Appropriate user and developer documentation (or not necessary)
• The test environment setup works and the intended behavior is reproducible in the test environment
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For further good practices have a look at our review guidelines.

src/caosdb/common/models.py

@@ -32,8 +32,8 @@ All additional classes are either important for the entities or the
 transactions.
 """
 
-from __future__ import print_function, unicode_literals
 from __future__ import annotations  # Can be removed with 3.10.
+from __future__ import print_function, unicode_literals
 
 import re
 import sys
@@ -51,8 +51,8 @@ from warnings import warn
 from caosdb.common.datatype import (BOOLEAN, DATETIME, DOUBLE, INTEGER, TEXT,
                                     is_list_datatype, is_reference)
 from caosdb.common.state import State
-from caosdb.common.utils import uuid, xml2str
 from caosdb.common.timezone import TimeZone
+from caosdb.common.utils import uuid, xml2str
 from caosdb.common.versioning import Version
 from caosdb.configuration import get_config
 from caosdb.connection.connection import get_connection
@@ -112,7 +112,7 @@ class Entity:
         self.__datatype = None
         self.datatype = datatype
         self.value = value
-        self.messages = _Messages()
+        self.messages = Messages()
         self.properties = _Properties()
         self.parents = _ParentList()
         self.path = None
@@ -419,7 +419,7 @@ class Entity:
             self.acl.is_permitted(permission=permission)
 
     def get_all_messages(self):
-        ret = _Messages()
+        ret = Messages()
         ret.append(self.messages)
 
         for p in self.properties:
@@ -1056,7 +1056,7 @@ out: List[Entity]
     def get_messages(self):
         """Get all messages of this entity.
 
-        @return: _Messages(list)
+        @return: Messages(list)
         """
 
         return self.messages
@@ -1064,9 +1064,9 @@ out: List[Entity]
     def get_warnings(self):
         """Get all warning messages of this entity.
 
-        @return _Messages(list): Warning messages.
+        @return Messages(list): Warning messages.
         """
-        ret = _Messages()
+        ret = Messages()
 
         for m in self.messages:
             if m.type.lower() == "warning":
@@ -1077,9 +1077,9 @@ out: List[Entity]
     def get_errors(self):
         """Get all error messages of this entity.
 
-        @return _Messages(list): Error messages.
+        @return Messages(list): Error messages.
         """
-        ret = _Messages()
+        ret = Messages()
 
         for m in self.messages:
             if m.type.lower() == "error":
@@ -1599,7 +1599,7 @@ class QueryTemplate():
         self._cuid = None
         self.value = None
         self.datatype = None
-        self.messages = _Messages()
+        self.messages = Messages()
         self.properties = None
         self.parents = None
         self.path = None
@@ -1719,7 +1719,7 @@ class QueryTemplate():
         return self.id is not None
 
     def get_errors(self):
-        ret = _Messages()
+        ret = Messages()
 
         for m in self.messages:
             if m.type.lower() == "error":
@@ -2399,7 +2399,7 @@ class _ParentList(list):
         raise KeyError(str(parent) + " not found.")
 
 
-class _Messages(dict):
+class Messages(list):
 
     """This 'kind of dictionary' stores error, warning, info, and other
     messages. The mentioned three messages types are messages of special use.
@@ -2417,21 +2417,21 @@ class _Messages(dict):
     and the same code (or no code). Every message
     MUST NOT occur more than once per entity (to which the message in question belongs).
 
-    If a message m2 is added while a messages m1 is already in this _Message object m2 will
+    If a message m2 is added while a messages m1 is already in this Message object m2 will
     OVERRIDE m1.
 
     Error, warning, and info messages will be deleted before any transaction.
 
     Examples:
-    <<< msgs = _Messages()
+    <<< msgs = Messages()
 
     <<< # create Message
     <<< msg = Message(type="HelloWorld", code=1, description="Greeting the world", body="Hello, world!")
 
-    <<< # append it to the _Messages
+    <<< # append it to the Messages
     <<< msgs.append(msg)
 
-    <<< # use _Messages as list of Message objects
+    <<< # use Messages as list of Message objects
     <<< for m in msgs:
     ...     assert isinstance(m,Message)
 
@@ -2464,7 +2464,8 @@ class _Messages(dict):
     """
 
     def clear_server_messages(self):
-        """Removes all error, warning and info messages."""
+        """Removes all messages of type error, warning and info."""
+        # TODO Why do we not remove ALL messages?
         rem = []
 
         for m in self:
@@ -2474,9 +2475,18 @@ class _Messages(dict):
         for m in rem:
             self.remove(m)
 
-        return self
-
+    #######################################################################
+    # can be removed after 01.07.24
+    # default implementation of list is sufficient
     def __setitem__(self, key, value):  # @ReservedAssignment
+        if not isinstance(value, Message):
+            warn("__setitem__ will in future only accept Message objects as second argument. "
+                 "You will no longe be"
+                 " able to pass bodys such that Message object is created on the fly",
+                 DeprecationWarning)
+        if not isinstance(key, int):
+            warn("__setitem__ will in future only accept int as first argument",
+                 DeprecationWarning)
         if isinstance(key, tuple):
             if len(key) == 2:
                 type = key[0]  # @ReservedAssignment
@@ -2487,7 +2497,7 @@ class _Messages(dict):
             else:
                 raise TypeError(
                     "('type', 'code'), ('type'), or 'type' expected.")
-        elif isinstance(key, _Messages._msg_key):
+        elif isinstance(key, Messages._msg_key):
             type = key._type  # @ReservedAssignment
             code = key._code
         else:
@@ -2508,13 +2518,19 @@ class _Messages(dict):
         if isinstance(value, Message):
             body = value.body
             description = value.description
+            m = Message
         else:
             body = value
             description = None
-        m = Message(type=type, code=code, description=description, body=body)
-        dict.__setitem__(self, _Messages._msg_key(type, code), m)
+            m = Message(type=type, code=code, description=description, body=body)
+        if isinstance(key, int):
+            super().__setitem__(key, m)
+        else:
+            self.append(m)
 
     def __getitem__(self, key):
+        if not isinstance(key, int):
+            warn("__getitem__ only supports integer keys in future.", DeprecationWarning)
         if isinstance(key, tuple):
             if len(key) == 2:
                 type = key[0]  # @ReservedAssignment
@@ -2525,113 +2541,117 @@ class _Messages(dict):
             else:
                 raise TypeError(
                     "('type', 'code'), ('type'), or 'type' expected.")
-        elif isinstance(key, int) and int(key) >= 0:
-            for m in self.values():
-                if key == 0:
-                    return m
-                else:
-                    key -= 1
-            type = key  # @ReservedAssignment
-            code = None
+        elif isinstance(key, int) and key >= 0:
+            return super().__getitem__(key)
         else:
             type = key  # @ReservedAssignment
             code = None
-        m = dict.__getitem__(self, _Messages._msg_key(type, code))
-
+        m = self.get(type, code)
+        if m is None:
+            return
         if m.description:
             return (m.description, m.body)
         else:
             return m.body
 
-    def __init__(self):
-        dict.__init__(self)
-
     def __delitem__(self, key):
         if isinstance(key, tuple):
-            if len(key) == 2:
-                type = key[0]  # @ReservedAssignment
-                code = key[1]
-            elif len(key) == 1:
-                type = key[0]  # @ReservedAssignment
-                code = None
-            else:
-                raise TypeError(
-                    "('type', 'code'), ('type'), or 'type' expected.")
+            warn("__delitem__ only supports integer keys in future.", DeprecationWarning)
+            if self.get(key[0], key[1]) is not None:
+                self.remove(self.get(key[0], key[1]))
         else:
-            type = key  # @ReservedAssignment
-            code = None
-
-        return dict.__delitem__(self, _Messages._msg_key(type, code))
+            super().__delitem__(key)
 
     def remove(self, obj, obj2=None):
-        if isinstance(obj, Message):
-            return dict.__delitem__(self, _Messages._msg_key.get(obj))
+        if obj2 is not None:
+            warn("Supplying a second argument to remove is deprecated.",
+                 DeprecationWarning)
+            super().remove(self.get(obj, obj2))
+        else:
+            super().remove(obj)
 
-        return self.__delitem__((obj, obj2))
+    def append(self, msg):
+        if isinstance(msg, Messages) or isinstance(msg, list):
+            warn("Supplying a list-like object to append is deprecated. Please use extend"
+                 " instead.", DeprecationWarning)
+            for m in msg:
+                self.append(m)
+            return
 
-    def get(self, type, code=None, default=None):  # @ReservedAssignment
-        try:
-            return dict.__getitem__(self, _Messages._msg_key(type, code))
-        except KeyError:
-            return default
+        super().append(msg)
 
-    def extend(self, messages):
-        self.append(messages)
+    @staticmethod
+    def _hash(t, c):
+        return hash(str(t).lower() + (str(",") + str(c) if c is not None else ''))
+    # end remove
+    #######################################################################
 
-        return self
+    def get(self, type, code=None, default=None, exact=False):  # @ReservedAssignment
+        """
+        returns a message from the list that kind of matches type and code
 
-    def append(self, msg):
-        if hasattr(msg, "__iter__"):
-            for m in msg:
-                self.append(m)
+        case and types (str/int) are ignored
 
-            return self
+        If no suitable message is found, the default argument is returned
+        If exact=True, the message has to match code and type exactly
+        """
+        if not exact:
+            warn("The fuzzy mode (exact=False) is deprecated. Please use exact in future.",
+                 DeprecationWarning)
+
+        for msg in self:
+            if exact:
+                if msg.type == type and msg.code == code:
+                    return msg
+            else:
+                if self._hash(msg.t, msg.c) == self._hash(type, code):
+                    return msg
 
-        if isinstance(msg, Message):
-            dict.__setitem__(self, _Messages._msg_key.get(msg), msg)
+        return default
 
-            return self
-        else:
-            raise TypeError("Argument was not a Message")
+    def to_xml(self, add_to_element):
+        for m in self:
+            melem = m.to_xml()
+            add_to_element.append(melem)
 
-        return self
+    def __repr__(self):
+        xml = etree.Element("Messages")
+        self.to_xml(xml)
 
-    def __iter__(self):
-        return dict.values(self).__iter__()
+        return xml2str(xml)
 
+    #######################################################################
+    # can be removed after 01.07.24
     class _msg_key:
 
         def __init__(self, type, code):  # @ReservedAssignment
+            warn("This class is deprecated.", DeprecationWarning)
             self._type = type
             self._code = code
 
         @staticmethod
         def get(msg):
-            return _Messages._msg_key(msg.type, msg.code)
+            return Messages._msg_key(msg.type, msg.code)
 
         def __eq__(self, obj):
             return self.__hash__() == obj.__hash__()
 
         def __hash__(self):
-            return hash(str(self._type).lower() + (str(",") +
-                                                   str(self._code) if self._code is not None else ''))
+            return
 
         def __repr__(self):
             return str(self._type) + (str(",") + str(self._code)
                                       if self._code is not None else '')
+    # end remove
+    #######################################################################
 
-    def to_xml(self, add_to_element):
-        for m in self:
-            melem = m.to_xml()
-            add_to_element.append(melem)
-
-        return self
-
-    def __repr__(self):
-        xml = etree.Element("Messages")
-        self.to_xml(xml)
 
-        return xml2str(xml)
+class _Messages(Messages):
+    def __init__(self, *args, **kwargs):
+        warn("_Messages is deprecated. "
+             "Use class Messages instead and beware of the slightly different API of the new"
+             " Messages class", DeprecationWarning)
+        super().__init__(*args, **kwargs)
 
 
 def _basic_sync(e_local, e_remote):
@@ -2834,7 +2854,7 @@ class Container(list):
         list.__init__(self)
         self._timestamp = None
         self._srid = None
-        self.messages = _Messages()
+        self.messages = Messages()
 
     def extend(self, entities):
         """Extend this Container by appending all single entities in the given
@@ -2927,11 +2947,11 @@ class Container(list):
     def get_errors(self):
         """Get all error messages of this container.
 
-        @return _Messages: Error messages.
+        @return Messages: Error messages.
         """
 
         if self.has_errors():
-            ret = _Messages()
+            ret = Messages()
 
             for m in self.messages:
                 if m.type.lower() == "error":
@@ -2944,11 +2964,11 @@ class Container(list):
     def get_warnings(self):
         """Get all warning messages of this container.
 
-        @return _Messages: Warning messages.
+        @return Messages: Warning messages.
         """
 
         if self.has_warnings():
-            ret = _Messages()
+            ret = Messages()
 
             for m in self.messages:
                 if m.type.lower() == "warning":
@@ -2959,7 +2979,7 @@ class Container(list):
             return None
 
     def get_all_messages(self):
-        ret = _Messages()
+        ret = Messages()
 
         for e in self:
             ret.extend(e.get_all_messages())
@@ -4309,7 +4329,7 @@ class Query():
         The query string.
     flags : dict of str
         A dictionary of flags to be send with the query request.
-    messages : _Messages()
+    messages : Messages()
         A container of messages included in the last query response.
     cached : bool
         indicates whether the server used the query cache for the execution of
@@ -4332,7 +4352,7 @@ class Query():
 
     def __init__(self, q):
         self.flags = dict()
-        self.messages = _Messages()
+        self.messages = Messages()
         self.cached = None
         self.etag = None
 
@@ -4456,6 +4476,10 @@ def execute_query(q, unique=False, raise_exception_on_error=True, cache=True, fl
 
 
 class DropOffBox(list):
+    def __init__(self, *args, **kwargs):
+        warn(DeprecationWarning(
+                "The DropOffBox is deprecated and will be removed in future."))
+        super().__init__(*args, **kwargs)
 
     path = None
 
@@ -4499,7 +4523,7 @@ class UserInfo():
 class Info():
 
     def __init__(self):
-        self.messages = _Messages()
+        self.messages = Messages()
         self.sync()
 
     def sync(self):