fix: filter invalid request bodies (#348)

whilst implementing better support for non-JSON content-types, I
realized that the stripe api defines a bunch of meaningless requests
bodies on their `GET` / `DELETE` requests that look like this:

```yaml
requestBody:
        content:
          application/x-www-form-urlencoded:
            encoding: {}
            schema:
              additionalProperties: false
              properties: {}
              type: object
        required: false
```

which is basically an `object` with no `properties` and no
`additionalProperties` allowed.

I'd probably have just ignored this, but the combination of this with
`application/x-www-form-urlencoded` meant it complicated adding support
for encoding bodies using `URLSearchParams`

I've raised stripe/openapi#170 but for now
lets just skip these and log a warning.

Author: mnahkies

integration-tests/typescript-angular/src/generated/stripe.yaml/client.service.ts

@@ -1,4 +1,5 @@
 import {generationLib} from "../../core/generation-lib"
+import {logger} from "../../core/logger"
 import type {
   IROperation,
   IRParameter,
@@ -99,7 +100,17 @@ export class ClientOperationBuilder {
     requestBodyParameter?: IRParameter
     requestBodyContentType?: string
   } {
-    return requestBodyAsParameter(this.operation)
+    const result = requestBodyAsParameter(this.operation)
+    const schema = result.requestBodyParameter?.schema
+
+    if (schema && this.models.isEmptyObject(schema)) {
+      logger.warn(
+        `[${this.route}]: skipping requestBody parameter that resolves to EmptyObject`,
+      )
+      return {}
+    }
+
+    return result
   }
 
   queryString(): string {

integration-tests/typescript-axios/src/generated/stripe.yaml/client.ts

@@ -233,11 +233,9 @@ export class TypeBuilder implements ICompilable {
             ? `[key: string]: ${union(additionalPropertiesType, "undefined")}`
             : ""
 
-          const emptyObject =
-            schemaObject.additionalProperties === false &&
-            properties.length === 0
-              ? this.addStaticType("EmptyObject")
-              : ""
+          const emptyObject = this.isEmptyObject(schemaObject)
+            ? this.addStaticType("EmptyObject")
+            : ""
 
           properties.push(additionalProperties)
 
@@ -263,4 +261,17 @@ export class TypeBuilder implements ICompilable {
   toCompilationUnit(): CompilationUnit {
     return new CompilationUnit(this.filename, this.imports, this.toString())
   }
+
+  isEmptyObject(schemaObject: MaybeIRModel) {
+    const dereferenced = this.input.schema(schemaObject)
+
+    return (
+      dereferenced.type === "object" &&
+      dereferenced.allOf.length === 0 &&
+      dereferenced.anyOf.length === 0 &&
+      dereferenced.oneOf.length === 0 &&
+      dereferenced.additionalProperties === false &&
+      Object.keys(dereferenced.properties).length === 0
+    )
+  }
 }

integration-tests/typescript-express/src/generated/stripe.yaml/generated.ts

@@ -1,4 +1,5 @@
 import type {Input} from "../../core/input"
+import {logger} from "../../core/logger"
 import type {
   IRModelObject,
   IROperation,
@@ -265,14 +266,27 @@ export class ServerOperationBuilder {
 
   private requestBodyParameter(schemaSymbolName: string): Parameters["body"] {
     const {requestBodyParameter} = requestBodyAsParameter(this.operation)
+
     const isRequired = Boolean(requestBodyParameter?.required)
+
     const schema = requestBodyParameter
       ? this.schemaBuilder.fromModel(
           requestBodyParameter.schema,
           requestBodyParameter.required,
           true,
         )
       : undefined
+
+    if (
+      requestBodyParameter &&
+      this.types.isEmptyObject(requestBodyParameter.schema)
+    ) {
+      logger.warn(
+        `[${this.route}]: skipping requestBody parameter that resolves to EmptyObject`,
+      )
+      return {type: "void", schema: undefined, isRequired: false}
+    }
+
     let type = "void"
 
     if (schema && requestBodyParameter) {