emberjs/ember.js · error · Error

Cannot set read-only property "${keyName}" on object: ${insp

Error message

Cannot set read-only property "${keyName}" on object: ${inspect(obj)}

What it means

Error "Cannot set read-only property "${keyName}" on object: ${inspect(obj)}" thrown in emberjs/ember.js.

Source

Thrown at packages/@ember/-internals/metal/lib/computed.ts:513

      if (_dependentKeys !== undefined) {
        updateTag(propertyTag, getChainTagsForKeys(obj, _dependentKeys, tagMeta, meta));

        if (DEBUG) {
          ALLOW_CYCLES!.set(propertyTag, true);
        }
      }

      meta.setRevisionFor(keyName, valueForTag(propertyTag));
    } finally {
      endPropertyChanges();
    }

    return ret;
  }

  _throwReadOnlyError(obj: object, keyName: string): never {
    throw new Error(`Cannot set read-only property "${keyName}" on object: ${inspect(obj)}`);
  }

  _set(obj: object, keyName: string, value: unknown, meta: Meta): unknown {
    let hadCachedValue = meta.revisionFor(keyName) !== undefined;
    let cachedValue = meta.valueFor(keyName);

    let ret;
    let { _setter } = this;

    setObserverSuspended(obj, keyName, true);

    try {
      ret = _setter!.call(obj, keyName, value, cachedValue);
    } finally {
      setObserverSuspended(obj, keyName, false);
    }

    // allows setter to return the same value that is cached already

View on GitHub (pinned to 26f97246a8)

When it happens

Trigger: Thrown at packages/@ember/-internals/metal/lib/computed.ts:513 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of emberjs/ember.js@26f97246a8 (2026-09-01). Data as JSON: /api/errors/bb4fe37d9f1db2e8. Report an issue: GitHub.