Check bindings out-of-bounds in strict mode

Author: szuend

src/decode/decode.test.ts

@@ -349,4 +349,32 @@ describe("decode", () => {
       "index into the 'names' array",
     );
   });
+
+  it("throws if GENERATED_RANGE_BINDINGS is out-of-bounds in strict mode", () => {
+    const encoder = new ItemEncoder();
+    encoder.addUnsignedVLQs(Tag.GENERATED_RANGE_START, 0, 0).finishItem();
+    encoder.addUnsignedVLQs(Tag.GENERATED_RANGE_BINDINGS).addSignedVLQs(2)
+      .finishItem();
+    encoder.addUnsignedVLQs(Tag.GENERATED_RANGE_END, 2).finishItem();
+    const map = createMap(encoder.encode(), ["foo"]);
+
+    assertThrows(
+      () => decode(map, { mode: DecodeMode.STRICT }),
+      Error,
+      "index into the 'names' array",
+    );
+  });
+
+  it("ignores if GENERATED_RANGE_BINDINGS is out-of-bounds in lax mode", () => {
+    const encoder = new ItemEncoder();
+    encoder.addUnsignedVLQs(Tag.GENERATED_RANGE_START, 0, 0).finishItem();
+    encoder.addUnsignedVLQs(Tag.GENERATED_RANGE_BINDINGS).addSignedVLQs(2)
+      .finishItem();
+    encoder.addUnsignedVLQs(Tag.GENERATED_RANGE_END, 2).finishItem();
+    const map = createMap(encoder.encode(), ["foo"]);
+
+    const info = decode(map, { mode: DecodeMode.LAX });
+
+    assertEquals(info.ranges[0]?.values, [""]);
+  });
 });

src/decode/decode.ts

@@ -320,10 +320,8 @@ class Decoder {
       if (valueIdx === -1) {
         range.values.push(null);
       } else {
-        range.values.push(this.#names[valueIdx]);
+        range.values.push(this.#resolveName(valueIdx));
       }
-
-      // TODO: Potentially throw if we decode an illegal index.
     }
   }