fix: throw Error for methods that PartialListCompositeType does not s…

…upport

packages/ssz/src/type/partialListComposite.ts

@@ -1,6 +1,5 @@
 import {fromSnapshot, zeroNode} from "@chainsafe/persistent-merkle-tree";
 import {CompositeType, CompositeView, CompositeViewDU} from "./composite";
-import {ListCompositeTreeView} from "../view/listComposite";
 import {ListCompositeOpts, ListCompositeType} from "./listComposite";
 import {PartialListCompositeTreeViewDU} from "../viewDU/partialListComposite";
 import {Snapshot} from "../util/types";
@@ -9,13 +8,37 @@ import {byteArrayEquals} from "../util/byteArray";
 /**
  * Similar to ListCompositeType, this is mainly used to create a PartialListCompositeTreeViewDU from a snapshot.
  * The ViewDU created is a partial tree created from a snapshot, not a full tree.
+ * Note that this class only inherits minimal methods as defined in ArrayType of ../view/arrayBasic.ts
+ * It'll throw errors for all other methods, most of the usage is in the ViewDU class.
  */
 export class PartialListCompositeType<
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   ElementType extends CompositeType<any, CompositeView<ElementType>, CompositeViewDU<ElementType>>
 > extends ListCompositeType<ElementType> {
   constructor(readonly elementType: ElementType, readonly limit: number, opts?: ListCompositeOpts) {
     super(elementType, limit, opts);
+
+    // only inherit methods in ArrayType of ../view/arrayBasic.ts
+    const inheritedMethods = [
+      "tree_getLength",
+      "tree_setLength",
+      "tree_getChunksNode",
+      "tree_chunksNodeOffset",
+      "tree_setChunksNode",
+    ];
+    const methodNames = Object.getOwnPropertyNames(ListCompositeType.prototype).filter(
+      (prop) =>
+        prop !== "constructor" &&
+        typeof (this as unknown as Record<string, unknown>)[prop] === "function" &&
+        !inheritedMethods.includes(prop)
+    );
+
+    // throw errors for all remaining methods
+    for (const methodName of methodNames) {
+      (this as unknown as Record<string, unknown>)[methodName] = () => {
+        throw new Error(`Method ${methodName} is not implemented for PartialListCompositeType`);
+      };
+    }
   }
 
   snapshotToViewDU(snapshot: Snapshot): PartialListCompositeTreeViewDU<ElementType> {
@@ -29,16 +52,4 @@ export class PartialListCompositeType<
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     return new PartialListCompositeTreeViewDU(this, rootNode, snapshot);
   }
-
-  getView(): ListCompositeTreeView<ElementType> {
-    throw new Error("View is not implemented for PartialListCompositeType");
-  }
-
-  getViewDU(): PartialListCompositeTreeViewDU<ElementType> {
-    throw new Error("Does not support PartialListCompositeType.getViewDU(), use fromSnapshot() instead");
-  }
-
-  toViewDU(): PartialListCompositeTreeViewDU<ElementType> {
-    throw new Error("Does not support PartialListCompositeType.toViewDU(), use fromSnapshot() instead");
-  }
 }

packages/ssz/src/viewDU/partialListComposite.ts

@@ -36,6 +36,8 @@ export class PartialListCompositeTreeViewDU<
     return super.toSnapshot(count);
   }
 
+  /** Methods in ArrayCompositeTreeViewDU */
+
   get(index: number): CompositeViewDU<ElementType> {
     if (index < this.snapshot.count) {
       throw new Error(`Cannot get index ${index} less than existing snapshot count ${this.snapshot.count}`);
@@ -68,6 +70,12 @@ export class PartialListCompositeTreeViewDU<
     throw new Error("getAllReadonlyValues() is not supported for PartialListCompositeTreeViewDU");
   }
 
+  // commit() is inherited from ArrayCompositeTreeViewDU
+
+  /** Methods in ListCompositeTreeViewDU */
+
+  // push() is inherited from ListCompositeTreeViewDU
+
   /**
    * Similar to ListCompositeTreeViewDU.sliceTo() but:
    * - throw error if index < snapshot.count - 1
@@ -122,22 +130,14 @@ export class PartialListCompositeTreeViewDU<
     return new PartialListCompositeTreeViewDU(this.type, newRootNode, ZERO_SNAPSHOT) as this;
   }
 
-  /**
-   * Similar to ListCompositeTreeViewDU.toValue() but we need to set undefined values for items 0 to snapshot.count - 1
-   */
-  toValue(): ValueOf<ElementType>[] {
-    const values = new Array<ValueOf<ElementType>>(this.length);
+  serializeToBytes(): number {
+    throw new Error("serializeToBytes() is not supported for PartialListCompositeTreeViewDU");
+  }
 
-    const snapshotCount = this.snapshot.count;
-    const allNodes = getNodesAtDepth(this._rootNode, this.type.depth, snapshotCount, this.length - snapshotCount);
-    const type = this.type.elementType;
-    // value of 0 to snapshot.count - 1 is from snapshot, and they are undefined
-    for (let i = snapshotCount; i < this.length; i++) {
-      values[i] = type.toValueFromViewDU(type.getViewDU(allNodes[i - snapshotCount]));
-    }
+  /** Methods in TreeViewDU */
 
-    return values;
-  }
+  // hashTreeRoot() is inherited from TreeViewDU
+  // batchHashTreeRoot() is inherited from TreeViewDU
 
   /**
    * Does not support serialize and deserialize, it works through snapshot.
@@ -159,6 +159,24 @@ export class PartialListCompositeTreeViewDU<
     }
   }
 
+  /**
+   * Mainly used for testing, to ensure the snapshot is correct.
+   * Set undefined values for items 0 to snapshot.count - 1
+   */
+  toValue(): ValueOf<ElementType>[] {
+    const values = new Array<ValueOf<ElementType>>(this.length);
+
+    const snapshotCount = this.snapshot.count;
+    const allNodes = getNodesAtDepth(this._rootNode, this.type.depth, snapshotCount, this.length - snapshotCount);
+    const type = this.type.elementType;
+    // value of 0 to snapshot.count - 1 is from snapshot, and they are undefined
+    for (let i = snapshotCount; i < this.length; i++) {
+      values[i] = type.toValueFromViewDU(type.getViewDU(allNodes[i - snapshotCount]));
+    }
+
+    return values;
+  }
+
   /**
    * Throw error because we only have partial tree in this case.
    */