Remove lazy imports (#1022)

After a few refactoring we can get rid of the lazy import callback and
simply import objects that we need directly.

Author: therve

.generator/src/generator/templates/model_generic.j2

@@ -1,14 +1,4 @@
 {%- set refs = get_references_for_model(model, name) %}
-{%- if refs %}
-def lazy_import():
-{%- for ref in refs %}
-    from {{ package }}.{{ version }}.model.{{ ref|safe_snake_case }} import {{ ref }}
-{%- endfor %}
-{# keep new line #}
-{%- for ref in refs %}
-    globals()["{{ ref }}"] = {{ ref }}
-{%- endfor %}
-{%- endif %}
 
 class {{ name }}(ModelNormal):
 
@@ -59,7 +49,9 @@ class {{ name }}(ModelNormal):
     @cached_property
     def additional_properties_type(_):
 {%- if refs %}
-        lazy_import()
+{%- for ref in refs %}
+        from {{ package }}.{{ version }}.model.{{ ref|safe_snake_case }} import {{ ref }}
+{%- endfor %}
 {%- endif %}
         return ({{ type_to_python(model["additionalProperties"]) }},)
 {%- endif %}
@@ -72,7 +64,9 @@ class {{ name }}(ModelNormal):
     @cached_property
     def openapi_types(_):
 {%- if refs %}
-        lazy_import()
+{%- for ref in refs %}
+        from {{ package }}.{{ version }}.model.{{ ref|safe_snake_case }} import {{ ref }}
+{%- endfor %}
 {%- endif %}
         return {
 {%- for attr in model.properties %}

.generator/src/generator/templates/model_oneof.j2

@@ -1,13 +1,4 @@
 {%- set refs = get_oneof_models(model) %}
-{%- if refs %}
-def lazy_import():
-{%- for ref in refs %}
-    from {{ package }}.{{ version }}.model.{{ ref|safe_snake_case }} import {{ ref }}
-{%- endfor %}
-{%- for ref in refs %}
-    globals()["{{ ref }}"] = {{ ref }}
-{%- endfor %}
-{%- endif %}
 
 class {{ name }}(ModelComposed):
 
@@ -48,7 +39,9 @@ class {{ name }}(ModelComposed):
         # classes don't exist yet because their module has not finished
         # loading
 {%- if refs %}
-        lazy_import()
+{%- for ref in refs %}
+        from {{ package }}.{{ version }}.model.{{ ref|safe_snake_case }} import {{ ref }}
+{%- endfor %}
 {%- endif %}
         return {
             "anyOf": [],

.generator/src/generator/templates/model_simple.j2

@@ -1,10 +1,4 @@
 {%- set ref = get_type_for_items(model) %}
-{%- if ref  %}
-def lazy_import():
-    from {{ package }}.{{ version }}.model.{{ ref|safe_snake_case }} import {{ ref }}
-
-    globals()["{{ ref }}"] = {{ ref }}
-{%- endif %}
 
 class {{ name }}(ModelSimple):
 
@@ -52,7 +46,7 @@ class {{ name }}(ModelSimple):
     @cached_property
     def openapi_types(_):
 {%- if ref %}
-        lazy_import()
+        from {{ package }}.{{ version }}.model.{{ ref|safe_snake_case }} import {{ ref }}
         return {
             "value": ([{{ ref }}],),
         }