fix(python): correctly handle nested structs-as-dict

packages/jsii-calc/lib/compliance.ts

@@ -2175,3 +2175,36 @@ class PrivateBell implements IBell {
         this.rung = true;
     }
 }
+
+/**
+ * This is here to check that we can pass a nested struct into a kwargs by specifying it as an
+ * in-line dictionary. This is cheating with the declared types, but Python people don't play by
+ * the rules much apparently.
+ */
+export interface RootStruct {
+    /**
+     * May not be empty.
+     */
+    readonly stringProp: string;
+    readonly nestedStruct?: NestedStruct;
+}
+export interface NestedStruct {
+    /**
+     * When provided, must be > 0.
+     */
+    readonly numberProp: number;
+}
+export class RootStructValidator {
+    public static validate(struct: RootStruct): void {
+        if (!struct.stringProp) {
+            throw new Error('Missing required field: stringProp');
+        }
+        if (struct.nestedStruct) {
+            if (struct.nestedStruct.numberProp <= 0) {
+                throw new Error('numberProp must be > 0');
+            }
+        }
+    }
+
+    private constructor() { }
+}

packages/jsii-calc/test/assembly.jsii

@@ -6799,6 +6799,38 @@
         }
       ]
     },
+    "jsii-calc.NestedStruct": {
+      "assembly": "jsii-calc",
+      "datatype": true,
+      "docs": {
+        "stability": "experimental"
+      },
+      "fqn": "jsii-calc.NestedStruct",
+      "kind": "interface",
+      "locationInModule": {
+        "filename": "lib/compliance.ts",
+        "line": 2191
+      },
+      "name": "NestedStruct",
+      "properties": [
+        {
+          "abstract": true,
+          "docs": {
+            "stability": "experimental",
+            "summary": "When provided, must be > 0."
+          },
+          "immutable": true,
+          "locationInModule": {
+            "filename": "lib/compliance.ts",
+            "line": 2195
+          },
+          "name": "numberProp",
+          "type": {
+            "primitive": "number"
+          }
+        }
+      ]
+    },
     "jsii-calc.NodeStandardLibrary": {
       "assembly": "jsii-calc",
       "docs": {
@@ -8215,6 +8247,90 @@
         }
       ]
     },
+    "jsii-calc.RootStruct": {
+      "assembly": "jsii-calc",
+      "datatype": true,
+      "docs": {
+        "remarks": "This is cheating with the declared types, but Python people don't play by\nthe rules much apparently.",
+        "stability": "experimental",
+        "summary": "This is here to check that we can pass a nested struct into a kwargs by specifying it as an in-line dictionary."
+      },
+      "fqn": "jsii-calc.RootStruct",
+      "kind": "interface",
+      "locationInModule": {
+        "filename": "lib/compliance.ts",
+        "line": 2184
+      },
+      "name": "RootStruct",
+      "properties": [
+        {
+          "abstract": true,
+          "docs": {
+            "stability": "experimental",
+            "summary": "May not be empty."
+          },
+          "immutable": true,
+          "locationInModule": {
+            "filename": "lib/compliance.ts",
+            "line": 2188
+          },
+          "name": "stringProp",
+          "type": {
+            "primitive": "string"
+          }
+        },
+        {
+          "abstract": true,
+          "docs": {
+            "stability": "experimental"
+          },
+          "immutable": true,
+          "locationInModule": {
+            "filename": "lib/compliance.ts",
+            "line": 2189
+          },
+          "name": "nestedStruct",
+          "optional": true,
+          "type": {
+            "fqn": "jsii-calc.NestedStruct"
+          }
+        }
+      ]
+    },
+    "jsii-calc.RootStructValidator": {
+      "assembly": "jsii-calc",
+      "docs": {
+        "stability": "experimental"
+      },
+      "fqn": "jsii-calc.RootStructValidator",
+      "kind": "class",
+      "locationInModule": {
+        "filename": "lib/compliance.ts",
+        "line": 2197
+      },
+      "methods": [
+        {
+          "docs": {
+            "stability": "experimental"
+          },
+          "locationInModule": {
+            "filename": "lib/compliance.ts",
+            "line": 2198
+          },
+          "name": "validate",
+          "parameters": [
+            {
+              "name": "struct",
+              "type": {
+                "fqn": "jsii-calc.RootStruct"
+              }
+            }
+          ],
+          "static": true
+        }
+      ],
+      "name": "RootStructValidator"
+    },
     "jsii-calc.RuntimeTypeChecking": {
       "assembly": "jsii-calc",
       "docs": {
@@ -10797,5 +10913,5 @@
     }
   },
   "version": "0.20.3",
-  "fingerprint": "r/K0k7ocrPmzUuFsCAvxLY2UdNEi6r/ruaoO3PnHiCA="
+  "fingerprint": "1F+uskR3++T5mjRcWge9oG3H/jJvXm1C3IhR1AwsBTE="
 }

packages/jsii-kernel/lib/serialization.ts

@@ -360,6 +360,11 @@ export const SERIALIZERS: {[k: string]: Serializer} = {
         value = data;
       }
 
+      // Python, for example, allows using plain mapping objects instead of Structs (dyanmic typing, YOLO!)
+      if (api.isWireMap(value)) {
+        value = value[api.TOKEN_MAP];
+      }
+
       value = validateRequiredProps(value as any, namedType.fqn, props);
 
       // Return a dict COPY, we have by-value semantics anyway.

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

@@ -665,6 +665,13 @@ class Struct extends BasePythonClassType {
     code.openBlock(`def __init__(${constructorArguments.join(', ')})`);
     this.emitConstructorDocstring(code);
 
+    // Re-type struct arguments that were passed as "dict"
+    for (const member of members.filter(m => m.isStruct(this.generator))) {
+      // Note that "None" is NOT an instance of dict (that's convenient!)
+      const typeName = resolver.resolve(member.type, { ignoreOptional: true });
+      code.line(`if isinstance(${member.pythonName}, dict): ${member.pythonName} = ${typeName}(**${member.pythonName})`);
+    }
+
     // Required properties, those will always be put into the dict
     code.line('self._values = {');
     for (const member of members.filter(m => !m.optional)) {
@@ -723,7 +730,7 @@ class StructField implements PythonBase {
   public readonly pythonName: string;
   public readonly jsiiName: string;
   public readonly docs?: spec.Docs;
-  private readonly type: spec.OptionalValue;
+  public readonly type: spec.OptionalValue;
 
   public constructor(public readonly prop: spec.Property) {
     this.pythonName = toPythonPropertyName(prop.name);

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/.jsii

@@ -6799,6 +6799,38 @@
         }
       ]
     },
+    "jsii-calc.NestedStruct": {
+      "assembly": "jsii-calc",
+      "datatype": true,
+      "docs": {
+        "stability": "experimental"
+      },
+      "fqn": "jsii-calc.NestedStruct",
+      "kind": "interface",
+      "locationInModule": {
+        "filename": "lib/compliance.ts",
+        "line": 2191
+      },
+      "name": "NestedStruct",
+      "properties": [
+        {
+          "abstract": true,
+          "docs": {
+            "stability": "experimental",
+            "summary": "When provided, must be > 0."
+          },
+          "immutable": true,
+          "locationInModule": {
+            "filename": "lib/compliance.ts",
+            "line": 2195
+          },
+          "name": "numberProp",
+          "type": {
+            "primitive": "number"
+          }
+        }
+      ]
+    },
     "jsii-calc.NodeStandardLibrary": {
       "assembly": "jsii-calc",
       "docs": {
@@ -8215,6 +8247,90 @@
         }
       ]
     },
+    "jsii-calc.RootStruct": {
+      "assembly": "jsii-calc",
+      "datatype": true,
+      "docs": {
+        "remarks": "This is cheating with the declared types, but Python people don't play by\nthe rules much apparently.",
+        "stability": "experimental",
+        "summary": "This is here to check that we can pass a nested struct into a kwargs by specifying it as an in-line dictionary."
+      },
+      "fqn": "jsii-calc.RootStruct",
+      "kind": "interface",
+      "locationInModule": {
+        "filename": "lib/compliance.ts",
+        "line": 2184
+      },
+      "name": "RootStruct",
+      "properties": [
+        {
+          "abstract": true,
+          "docs": {
+            "stability": "experimental",
+            "summary": "May not be empty."
+          },
+          "immutable": true,
+          "locationInModule": {
+            "filename": "lib/compliance.ts",
+            "line": 2188
+          },
+          "name": "stringProp",
+          "type": {
+            "primitive": "string"
+          }
+        },
+        {
+          "abstract": true,
+          "docs": {
+            "stability": "experimental"
+          },
+          "immutable": true,
+          "locationInModule": {
+            "filename": "lib/compliance.ts",
+            "line": 2189
+          },
+          "name": "nestedStruct",
+          "optional": true,
+          "type": {
+            "fqn": "jsii-calc.NestedStruct"
+          }
+        }
+      ]
+    },
+    "jsii-calc.RootStructValidator": {
+      "assembly": "jsii-calc",
+      "docs": {
+        "stability": "experimental"
+      },
+      "fqn": "jsii-calc.RootStructValidator",
+      "kind": "class",
+      "locationInModule": {
+        "filename": "lib/compliance.ts",
+        "line": 2197
+      },
+      "methods": [
+        {
+          "docs": {
+            "stability": "experimental"
+          },
+          "locationInModule": {
+            "filename": "lib/compliance.ts",
+            "line": 2198
+          },
+          "name": "validate",
+          "parameters": [
+            {
+              "name": "struct",
+              "type": {
+                "fqn": "jsii-calc.RootStruct"
+              }
+            }
+          ],
+          "static": true
+        }
+      ],
+      "name": "RootStructValidator"
+    },
     "jsii-calc.RuntimeTypeChecking": {
       "assembly": "jsii-calc",
       "docs": {
@@ -10797,5 +10913,5 @@
     }
   },
   "version": "0.20.3",
-  "fingerprint": "r/K0k7ocrPmzUuFsCAvxLY2UdNEi6r/ruaoO3PnHiCA="
+  "fingerprint": "1F+uskR3++T5mjRcWge9oG3H/jJvXm1C3IhR1AwsBTE="
 }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/INestedStruct.cs

@@ -0,0 +1,21 @@
+using Amazon.JSII.Runtime.Deputy;
+
+namespace Amazon.JSII.Tests.CalculatorNamespace
+{
+    /// <remarks>
+    /// stability: Experimental
+    /// </remarks>
+    [JsiiInterface(nativeType: typeof(INestedStruct), fullyQualifiedName: "jsii-calc.NestedStruct")]
+    public interface INestedStruct
+    {
+        /// <summary>When provided, must be > 0.</summary>
+        /// <remarks>
+        /// stability: Experimental
+        /// </remarks>
+        [JsiiProperty(name: "numberProp", typeJson: "{\"primitive\":\"number\"}")]
+        double NumberProp
+        {
+            get;
+        }
+    }
+}