Project System Extensibility Breaking Changes for Visual Studio 2019

December 13, 2018 · View on GitHub

We have made several breaking changes for the next version of Project System Extensibility. Our goal with these changes is to provide a consistent assembly name over releases, simplified namespaces, and new features. Below is a list of these changes.

For breaking changes made in previous releases:

Changed the type of the Services object

The type Services object of IProjectService/UnconfiguredProject/ConfiguredProject has been changed from interface to abstract class, so new services can be added without introducing breaking changes in the future.

While there is no code change needed to adopt this breaking change, a rebuild of the component is required with the Visual Studio 2019 version of CPS reference assembly make the component to work in Visual Studio 2019.

Some snapshot interfaces no longer inherit from IProjectVersionedValue

The following interfaces no longer inherit from IProjectVersionedValue:

Interface
IProjectSnapshot
IProjectRuleSnapshot
IProjectSharedFoldersSnapshot
IProjectImportTreeSnapshot

In most cases, we added a new Value property to the interface; originally it was inherited from IProjectVersionedValue<T>.

Any code using the version number in those snapshots should use the version number in the dataflow directly.

IProjectSnapshot.Value has been marked as obsolete, please use IProjectSnapshot.ProjectInstance.

This change was made to have a consistent style in all dataflow services and to reuse unchanged immutable objects to reduce allocations (instead of creating new instances that include version only changes).

IBuildLoggerProvider has been marked as obsolete, and is no longer called

Code should be changed to use IBuildLoggerProviderAsync instead

IVsLoggerEventProcessor is removed

It was marked as obsolete in the previous release, and not called by the product.

Mitigation: use IVsLoggerEventProcessor2 instead

Property ActiveConfigurationChangedEventArgs.ActiveConfiguredProjectProviderDataSourceVersion is removed

It was marked as obsolete in previews version.

Enum value ProjectFaultSeverity.Crippling has been removed.

It was renamed to LimitedFunctionality in Visual Studio 2017 updates, and the old enum value has been marked as obsolete for a while.

LazyFill value has been removed from IProjectTreeSnapshot and TreeUpdateResult

This value was not used and maintained since Dev 14.

IProjectTree.PropertySheet is marked as obsolete and no longer saved in the tree

We don't expect it to be used.

IProjectLockService introduces a new set of delegate based API to replace the current using style API to avoid potential deadlocks

The old using style API has not been removed or marked as obsolete at this point of time, so no action is required.

But we will eventually mark them as obsolete later, so plan some time to move to the new API after Preview 1.

Before:

using (var access = await this.ProjectLockService.ReadLockAsync(cancellationToken))
{
    var project = await access.GetProjectAsync(this.ConfiguredProject);
    // Use project...
}

After:

await this.ProjectLockService.ReadLockAsync(
    async access =>
    {
        Project project = await access.GetProjectAsync(this.ConfiguredProject);
        // Use project...
    },
    cancellationToken);

New Slim DataFlow blocks

To reduce the memory usage of dataflow blocks, CPS introduces a new custom set of slim dataflow blocks corresponding to TransformBlock/ActionBlock/BroadcastBlocks. While this is not a breaking change, we recommend CPS extensions to start using the new blocks.

The new blocks allow CPS dataflow to skip middle versions easier, but may introduce some behavior changes.

Before:

var actionBlock = new ActionBlock<IProjectVersionedValue<IProjectSubscriptionUpdate>>(
    this.OnSubscriptionUpdate,
    new ExecutionDataflowBlockOptions { NameFormat = "My Block {1}"});

After:

var actionBlock = DataflowBlockSlim.CreateActionBlock<IProjectVersionedValue<IProjectSubscriptionUpdate>>(
    this.OnSubscriptionUpdate,
    nameFormat: "My Block {1}");

IProjectSubscriptionServices behavior changes

When you chain the dataflow with initialDataAsNew false, the ProjectChangeDescription.Before is now the same as ProjectChangeDescription.After.

Previously, the Before property will provide an empty snapshot.

If you receive data from those dataflow blocks directly, you will always get the latest snapshots with an empty change delta (Change.Before is always the same as Change.After).

IProjectTree.IsLinked is now preserved as a flag in the project tree flags

This doesn't affect code that access the property, but only tree providers that create linked item node.