Packages can have dependencies on platform features and/or other packages. You can review and manage these dependencies through the usage of the Package detail page and the use of dynamic coding conventions as described here.
While some features of Salesforce are common, customers can purchase different editions and features according to their needs. Developer Edition organizations have access to most of these features for free. This means that as you develop your application, it is important to understand when and when not to use those features.
By default, when referencing a certain Standard Object, field, or component type, you will generate a prerequisite dependency on your package, which your customers will need to have before they can complete the installation. Some Salesforce features, for example Multi-Currency or Chatter, have either a configuration or, in some cases, a cost impact to your users (different org editions). Carefully consider which features your package is dependent on.
Most of the feature dependencies, though not all, are visible via the View Dependencies button on the Package details page (this information is also available on the Upload page, allowing you to make a final check). It is a good practice to add this check into your packaging procedures to ensure that no unwanted dependencies have crept in. Clicking on this button, for the package that we have been building in this chapter so far, confirms that there are no dependencies.
Once you have checked your dependencies, click on the Upload button. You will be prompted to give a name and version to your package. The version will be managed for you in subsequent releases. Packages are uploaded in one of two modes (beta or release). We will perform a release upload by selecting the Managed - Released option from the Release Type field, so make sure you are happy with the objects created in the earlier section of this chapter, as they cannot easily be changed after this point.
Once you are happy with the information on the screen, click on the Upload button once again to begin the packaging process. Once the upload process completes, you will see a confirmation page as follows:
Packages can be uploaded in one of two states as described here:
Release packages can be installed into subscriber production orgs and also provide an upgrade path from previous releases. The downside is that you cannot delete the previously released components and change certain things such as a field's type. Changes to the components that are marked global, such as Apex Code and Visualforce components, are also restricted. While Salesforce is gradually enhancing the platform to provide the ability to modify certain released aspects, you need to be certain that your application release is stable before selecting this option.
Beta packages cannot be installed into subscriber production orgs; you can install only into Developer Edition (such as your testing org), sandbox, or Partner Portal created orgs. Also, Beta packages cannot be upgraded once installed; hence, this is the reason why Salesforce does not permit their installation into production orgs. The key benefit is in the ability to continue to change new components of the release, to address bugs and features relating to user feedback.
The ability to delete previously-published components (uploaded within a release package) is, at the time of writing this book, in pilot. It can be enabled through raising a support case with Salesforce Support. Once you have understood the full implications, they will enable it.
At this stage in the book, we have simply added some Custom Objects. So, the upload should complete reasonably quickly. Note that what you're actually uploading to is AppExchange, which will be covered in the following sections.
It is possible to make some Salesforce features and/or base package component references (Custom Objects and fields) an optional aspect of your application. There are two approaches to this, depending on the type of the feature.
For example, the Multi-Currency feature adds a CurrencyIsoCode field to the standard and Custom Objects. If you explicitly reference this field, for example in your Apex or Visualforce pages, you will incur a hard dependency on your package. If you want to avoid this and make it a configuration option (for example) in your application, you can utilize dynamic Apex and Visualforce.
If you wish to package component types that are only available in subscriber orgs of certain editions, you can choose to include these in extension packages. For example, you may wish to support Professional Edition, which does not support record types. In this case, create an Enterprise Edition extension package for your application's functionality, which leverages the functionality from this edition.