fix(python): maintain inheritance chain for structs (#482)

Because structs all inherit from TypedDict, and TypedDict erases the
inheritance chain of structs, we have to maintain a copy of the
inheritance hierarchy on the class objects, for later use during
doc generation.

This addresses (part of) #473.

packages/jsii-pacmak/lib/targets/python.ts

@@ -641,6 +641,7 @@ class TypedDict extends BasePythonClassType {
         // and implement this "split" class logic.
 
         const classParams = this.getClassParams(resolver);
+        const baseInterfaces = classParams.slice(0, classParams.length - 1);
 
         const mandatoryMembers = this.members.filter(
             item => item instanceof TypedDictProperty ? !item.optional : true
@@ -655,14 +656,15 @@ class TypedDict extends BasePythonClassType {
 
             // We'll emit the optional members first, just because it's a little nicer
             // for the final class in the chain to have the mandatory members.
+            code.line(`@jsii.data_type_optionals(jsii_struct_bases=[${baseInterfaces.join(', ')}])`);
             code.openBlock(`class _${this.name}(${classParams.concat(["total=False"]).join(", ")})`);
             for (const member of optionalMembers) {
                 member.emit(code, resolver);
             }
             code.closeBlock();
 
             // Now we'll emit the mandatory members.
-            code.line(`@jsii.data_type(jsii_type="${this.fqn}")`);
+            code.line(`@jsii.data_type(jsii_type="${this.fqn}", jsii_struct_bases=[_${this.name}])`);
             code.openBlock(`class ${this.name}(_${this.name})`);
             emitDocString(code, this.docs);
             for (const [member, sep] of separate(sortMembers(mandatoryMembers, resolver))) {
@@ -671,7 +673,7 @@ class TypedDict extends BasePythonClassType {
             }
             code.closeBlock();
         } else {
-            code.line(`@jsii.data_type(jsii_type="${this.fqn}")`);
+            code.line(`@jsii.data_type(jsii_type="${this.fqn}", jsii_struct_bases=[${baseInterfaces.join(', ')}])`);
 
             // In this case we either have no members, or we have all of one type, so
             // we'll see if we have any optional members, if we don't then we'll use

packages/jsii-pacmak/test/expected.jsii-calc-base/python/src/scope/jsii_calc_base/__init__.py

@@ -32,7 +32,7 @@ def type_name(self) -> typing.Any:
 class _BaseProxy(Base):
     pass
 
-@jsii.data_type(jsii_type="@scope/jsii-calc-base.BaseProps")
+@jsii.data_type(jsii_type="@scope/jsii-calc-base.BaseProps", jsii_struct_bases=[scope.jsii_calc_base_of_base.VeryBaseProps])
 class BaseProps(scope.jsii_calc_base_of_base.VeryBaseProps, jsii.compat.TypedDict):
     bar: str
 

packages/jsii-pacmak/test/expected.jsii-calc-lib/python/src/scope/jsii_calc_lib/__init__.py

@@ -97,10 +97,11 @@ def baz(self) -> None:
         return jsii.invoke(self, "baz", [])
 
 
+@jsii.data_type_optionals(jsii_struct_bases=[])
 class _MyFirstStruct(jsii.compat.TypedDict, total=False):
     firstOptional: typing.List[str]
 
-@jsii.data_type(jsii_type="@scope/jsii-calc-lib.MyFirstStruct")
+@jsii.data_type(jsii_type="@scope/jsii-calc-lib.MyFirstStruct", jsii_struct_bases=[_MyFirstStruct])
 class MyFirstStruct(_MyFirstStruct):
     """This is the first struct we have created in jsii."""
     anumber: jsii.Number
@@ -109,7 +110,7 @@ class MyFirstStruct(_MyFirstStruct):
     astring: str
     """A string value."""
 
-@jsii.data_type(jsii_type="@scope/jsii-calc-lib.StructWithOnlyOptionals")
+@jsii.data_type(jsii_type="@scope/jsii-calc-lib.StructWithOnlyOptionals", jsii_struct_bases=[])
 class StructWithOnlyOptionals(jsii.compat.TypedDict, total=False):
     """This is a struct with only optional properties."""
     optional1: str

packages/jsii-pacmak/test/expected.jsii-calc/python/src/jsii_calc/__init__.py

@@ -412,7 +412,7 @@ def value(self) -> jsii.Number:
         return jsii.get(self, "value")
 
 
-@jsii.data_type(jsii_type="jsii-calc.CalculatorProps")
+@jsii.data_type(jsii_type="jsii-calc.CalculatorProps", jsii_struct_bases=[])
 class CalculatorProps(jsii.compat.TypedDict, total=False):
     """Properties for Calculator."""
     initialValue: jsii.Number
@@ -571,13 +571,14 @@ def __init__(self) -> None:
 
 
 
+@jsii.data_type_optionals(jsii_struct_bases=[scope.jsii_calc_lib.MyFirstStruct])
 class _DerivedStruct(scope.jsii_calc_lib.MyFirstStruct, jsii.compat.TypedDict, total=False):
     anotherOptional: typing.Mapping[str,scope.jsii_calc_lib.Value]
     """This is optional."""
     optionalAny: typing.Any
     optionalArray: typing.List[str]
 
-@jsii.data_type(jsii_type="jsii-calc.DerivedStruct")
+@jsii.data_type(jsii_type="jsii-calc.DerivedStruct", jsii_struct_bases=[_DerivedStruct])
 class DerivedStruct(_DerivedStruct):
     """A struct which derives from another struct."""
     anotherRequired: datetime.datetime
@@ -711,7 +712,7 @@ def prop2_is_undefined(cls) -> typing.Any:
         return jsii.sinvoke(cls, "prop2IsUndefined", [])
 
 
-@jsii.data_type(jsii_type="jsii-calc.EraseUndefinedHashValuesOptions")
+@jsii.data_type(jsii_type="jsii-calc.EraseUndefinedHashValuesOptions", jsii_struct_bases=[])
 class EraseUndefinedHashValuesOptions(jsii.compat.TypedDict, total=False):
     option1: str
 
@@ -731,7 +732,7 @@ def success(self) -> bool:
         return jsii.get(self, "success")
 
 
-@jsii.data_type(jsii_type="jsii-calc.ExtendsInternalInterface")
+@jsii.data_type(jsii_type="jsii-calc.ExtendsInternalInterface", jsii_struct_bases=[])
 class ExtendsInternalInterface(jsii.compat.TypedDict):
     boom: bool
 
@@ -828,7 +829,7 @@ def struct_literal(self) -> scope.jsii_calc_lib.StructWithOnlyOptionals:
         return jsii.get(self, "structLiteral")
 
 
-@jsii.data_type(jsii_type="jsii-calc.Greetee")
+@jsii.data_type(jsii_type="jsii-calc.Greetee", jsii_struct_bases=[])
 class Greetee(jsii.compat.TypedDict, total=False):
     """These are some arguments you can pass to a method."""
     name: str
@@ -1616,7 +1617,7 @@ def private(self, value: str):
         return jsii.set(self, "private", value)
 
 
-@jsii.data_type(jsii_type="jsii-calc.ImplictBaseOfBase")
+@jsii.data_type(jsii_type="jsii-calc.ImplictBaseOfBase", jsii_struct_bases=[scope.jsii_calc_base.BaseProps])
 class ImplictBaseOfBase(scope.jsii_calc_base.BaseProps, jsii.compat.TypedDict):
     goo: datetime.datetime
 
@@ -1635,13 +1636,13 @@ def bar(self, value: typing.Optional[str]):
             return jsii.set(self, "bar", value)
 
 
-    @jsii.data_type(jsii_type="jsii-calc.InterfaceInNamespaceIncludesClasses.Hello")
+    @jsii.data_type(jsii_type="jsii-calc.InterfaceInNamespaceIncludesClasses.Hello", jsii_struct_bases=[])
     class Hello(jsii.compat.TypedDict):
         foo: jsii.Number
 
 
 class InterfaceInNamespaceOnlyInterface:
-    @jsii.data_type(jsii_type="jsii-calc.InterfaceInNamespaceOnlyInterface.Hello")
+    @jsii.data_type(jsii_type="jsii-calc.InterfaceInNamespaceOnlyInterface.Hello", jsii_struct_bases=[])
     class Hello(jsii.compat.TypedDict):
         foo: jsii.Number
 
@@ -1966,7 +1967,7 @@ def jsii_agent(cls) -> typing.Optional[str]:
         return jsii.sget(cls, "jsiiAgent")
 
 
-@jsii.data_type(jsii_type="jsii-calc.LoadBalancedFargateServiceProps")
+@jsii.data_type(jsii_type="jsii-calc.LoadBalancedFargateServiceProps", jsii_struct_bases=[])
 class LoadBalancedFargateServiceProps(jsii.compat.TypedDict, total=False):
     """jsii#298: show default values in sphinx documentation, and respect newlines."""
     containerPort: jsii.Number
@@ -2148,10 +2149,11 @@ def change_me_to_undefined(self, value: typing.Optional[str]):
         return jsii.set(self, "changeMeToUndefined", value)
 
 
+@jsii.data_type_optionals(jsii_struct_bases=[])
 class _NullShouldBeTreatedAsUndefinedData(jsii.compat.TypedDict, total=False):
     thisShouldBeUndefined: typing.Any
 
-@jsii.data_type(jsii_type="jsii-calc.NullShouldBeTreatedAsUndefinedData")
+@jsii.data_type(jsii_type="jsii-calc.NullShouldBeTreatedAsUndefinedData", jsii_struct_bases=[_NullShouldBeTreatedAsUndefinedData])
 class NullShouldBeTreatedAsUndefinedData(_NullShouldBeTreatedAsUndefinedData):
     arrayWithThreeElementsAndUndefinedAsSecondArgument: typing.List[typing.Any]
 
@@ -2251,7 +2253,7 @@ def arg3(self) -> typing.Optional[datetime.datetime]:
         return jsii.get(self, "arg3")
 
 
-@jsii.data_type(jsii_type="jsii-calc.OptionalStruct")
+@jsii.data_type(jsii_type="jsii-calc.OptionalStruct", jsii_struct_bases=[])
 class OptionalStruct(jsii.compat.TypedDict, total=False):
     field: str
 
@@ -2877,10 +2879,11 @@ def value(self) -> jsii.Number:
         return jsii.get(self, "value")
 
 
+@jsii.data_type_optionals(jsii_struct_bases=[])
 class _UnionProperties(jsii.compat.TypedDict, total=False):
     foo: typing.Union[str, jsii.Number]
 
-@jsii.data_type(jsii_type="jsii-calc.UnionProperties")
+@jsii.data_type(jsii_type="jsii-calc.UnionProperties", jsii_struct_bases=[_UnionProperties])
 class UnionProperties(_UnionProperties):
     bar: typing.Union[str, jsii.Number, "AllTypes"]
 

packages/jsii-python-runtime/src/jsii/__init__.py

@@ -7,6 +7,7 @@
     JSIIAbstractClass,
     enum,
     data_type,
+    data_type_optionals,
     implements,
     interface,
     member,
@@ -44,6 +45,7 @@
     "Number",
     "enum",
     "data_type",
+    "data_type_optionals",
     "implements",
     "interface",
     "member",

packages/jsii-python-runtime/src/jsii/_runtime.py

@@ -84,15 +84,24 @@ def deco(cls):
     return deco
 
 
-def data_type(*, jsii_type):
+def data_type(*, jsii_type, jsii_struct_bases):
     def deco(cls):
         cls.__jsii_type__ = jsii_type
+        cls.__jsii_struct_bases__ = jsii_struct_bases
         _reference_map.register_data_type(cls)
         return cls
 
     return deco
 
 
+def data_type_optionals(*, jsii_struct_bases):
+    def deco(cls):
+        cls.__jsii_struct_bases__ = jsii_struct_bases
+        return cls
+
+    return deco
+
+
 def member(*, jsii_name):
     def deco(fn):
         fn.__jsii_name__ = jsii_name

packages/jsii-python-runtime/tests/test_python.py

@@ -2,14 +2,40 @@
 import pytest
 
 from jsii.errors import JSIIError
-from jsii_calc import Calculator
+import jsii_calc
 
 
 class TestErrorHandling:
     def test_jsii_error(self):
-        obj = Calculator()
+        obj = jsii_calc.Calculator()
 
         with pytest.raises(
             JSIIError, match="Class jsii-calc.Calculator doesn't have a method"
         ):
             jsii.kernel.invoke(obj, "nonexistentMethod")
+
+    def test_inheritance_maintained(self):
+        """Check that for JSII struct types we can get the inheritance tree in some way."""
+        # inspect.getmro() won't work because of TypedDict, but we add another annotation
+        bases = find_struct_bases(jsii_calc.DerivedStruct)
+
+        base_names = [b.__name__ for b  in bases]
+
+        assert base_names == ['DerivedStruct', '_DerivedStruct', 'MyFirstStruct', '_MyFirstStruct']
+
+
+
+def find_struct_bases(x):
+    ret = []
+    seen = set([])
+
+    def recurse(s):
+        if s not in seen:
+            ret.append(s)
+            seen.add(s)
+            bases = getattr(s, '__jsii_struct_bases__', [])
+            for base in bases:
+                recurse(base)
+
+    recurse(x)
+    return ret