Added fallback bean for when no implementation is found for a bean type

Author: NathanJPhillips

env-model-generator/src/model.ts

@@ -182,6 +182,37 @@ export class Bean implements IBean {
   }
 }
 
+export class UndefinedBean implements IBean {
+  private readonly typeName: string;
+  public readonly name: string;
+  public readonly IsAnonymous = true;
+
+  public constructor(identifier: string, typeName: string) {
+    this.name = identifier;
+    this.typeName = typeName;
+    Repository.registerBean(this);
+    Repository.registerIdForClass(this.typeName, this.name);
+  }
+
+  public get getter(): string {
+    return `get${upperInitialChar(this.name)}`;
+  }
+
+  public get javaMembers(): Member[] {
+    return [
+      new Method(
+        `public static ${this.typeName} ${this.getter}()`,
+        [
+          new Return(new FnCall("org.cprover.CProver.nondetWithNull", [])),
+        ],
+        []),
+        new BlankLine(),
+    ];
+  }
+
+  public readonly exceptions: string[] = [];
+}
+
 export namespace Repository {
   const beans = new NameMap<IBean>();
 

env-model-generator/src/parseJson.ts

@@ -180,10 +180,18 @@ function parseJsonBean(id: string, namedMethod: NamedBeanDefinitionMethod): mode
 }
 
 function getBeanForClass(className: string, userString: string): model.BeanRefValue {
-  const fieldBeanId = model.Repository.tryGetIdByClass(className);
+  let fieldBeanId = model.Repository.tryGetIdByClass(className);
   if (fieldBeanId === undefined)
-    throw new ConfigParseError(
-      `${userString} depends on a class '${className}' `
-        + `that has ${model.Repository.hasMultipleBeansForClass(className) ? "multiple" : "no"} implementations`);
+  {
+    if (model.Repository.hasMultipleBeansForClass(className))
+      throw new ConfigParseError(`${userString} depends on a class '${className}' that has multiple implementations`);
+    // Return a default, fall-back bean implementation
+    const id = lowerInitialChar(<string>className.split(".").pop());
+    console.warn(`${userString} depends on a class '${className}' that has no implementations, `
+      + `creating a new bean called '${id}' using non-deterministic initialisation`);
+    checkBeanId(id, `Auto-generated component to satisfy dependency for '${className}'`);
+    const bean = new model.UndefinedBean(id, className);
+    fieldBeanId = bean.name;
+  }
   return new model.BeanRefValue(fieldBeanId);
 }