Process empty dict as Dict type

TODO.md

@@ -3,7 +3,7 @@
 - Features
     - Models layer
         - [X] Data variant converting
-            - [ ] Change empty dict to actual dict type, not empty models
+            - [X] Change empty dict to actual dict type, not empty models
         - [X] Data variant merging
         - [X] Create and register models
         - [X] Merge meta-models and extract common ones

json_to_models/generator.py

@@ -77,6 +77,8 @@ def _detect_type(self, value, convert_dict=True) -> MetaData:
 
         # Dict should be processed as another model if convert_dict is enabled
         elif isinstance(value, dict):
+            if not value:
+                return DDict(Unknown)
             for reg in self.dict_keys_regex:
                 if all(map(reg.match, value.keys())):
                     convert_dict = False
@@ -91,10 +93,8 @@ def _detect_type(self, value, convert_dict=True) -> MetaData:
                     if len(union.types) == 1:
                         return DDict(*union.types)
                     return DDict(union)
-                elif types:
-                    return DDict(*types)
                 else:
-                    return DDict(Unknown)
+                    return DDict(*types)
 
         # null interpreted as is and will be processed later on Union merge stage
         elif value is None:

json_to_models/registry.py

@@ -1,6 +1,6 @@
 from collections import OrderedDict, defaultdict
 from itertools import chain, combinations
-from typing import Dict, List, Set, Tuple
+from typing import Dict, Iterable, List, Set, Tuple
 
 from ordered_set import OrderedSet
 
@@ -147,7 +147,7 @@ def merge_models(self, generator, strict=False) -> List[Tuple[ModelMeta, Set[Mod
                 models2merge[model_b].add(model_a)
 
         # Groups of models to merge
-        groups: List[Set[ModelMeta]] = [{model, *models} for model, models in models2merge.items()]
+        groups: Iterable[Set[ModelMeta]] = [{model, *models} for model, models in models2merge.items()]
         # Make groups non-overlapping.
         # This is not optimal algorithm but it works and we probably will not have thousands of models here.
         flag = True

test/test_code_generation/test_models_code_generator.py

@@ -2,8 +2,8 @@
 
 import pytest
 
-from json_to_models.dynamic_typing import (AbsoluteModelRef, DList, DOptional, IntString, ModelMeta, ModelPtr,
-                                           compile_imports)
+from json_to_models.dynamic_typing import (AbsoluteModelRef, DDict, DList, DOptional, IntString, ModelMeta, ModelPtr,
+                                           Unknown, compile_imports)
 from json_to_models.models import indent, sort_fields
 from json_to_models.models.base import GenericModelCodeGenerator, generate_code
 
@@ -101,7 +101,8 @@ class Test:
         "model": ("Test", {
             "foo": int,
             "baz": DOptional(DList(DList(str))),
-            "bar": IntString
+            "bar": IntString,
+            "d": DDict(Unknown)
         }),
         "fields_data": {
             "foo": {
@@ -115,25 +116,31 @@ class Test:
             "bar": {
                 "name": "bar",
                 "type": "IntString"
+            },
+            "d": {
+                "name": "d",
+                "type": "Dict[str, Any]"
             }
         },
         "fields": {
             "imports": "from json_to_models.dynamic_typing import IntString\n"
-                       "from typing import List, Optional",
+                       "from typing import Any, Dict, List, Optional",
             "fields": [
                 "foo: int",
                 "bar: IntString",
+                "d: Dict[str, Any]",
                 "baz: Optional[List[List[str]]]",
             ]
         },
         "generated": trim("""
         from json_to_models.dynamic_typing import IntString
-        from typing import List, Optional
+        from typing import Any, Dict, List, Optional
 
 
         class Test:
             foo: int
             bar: IntString
+            d: Dict[str, Any]
             baz: Optional[List[List[str]]]
         """)
     }

test/test_generator/test_detect_type.py

@@ -17,7 +17,8 @@
     pytest.param("1", IntString, id="int_str"),
     pytest.param("1.0", FloatString, id="float_str"),
     pytest.param("true", BooleanString, id="bool_str"),
-    pytest.param({"test_dict_field_a": 1, "test_dict_field_b": "a"}, DDict(DUnion(int, str)), id="dict")
+    pytest.param({"test_dict_field_a": 1, "test_dict_field_b": "a"}, DDict(DUnion(int, str)), id="dict"),
+    pytest.param({}, DDict(Unknown))
 ]
 
 test_dict = {param.id: param.values[0] for param in test_data}