With a standard dbContext (Scoped), my context is being shared across requests.

[mgallig]

Steps to reproduce

Add a scoped lifetime datacontext

In my controller it is injected in this way

  private ApplicationDbContext _context;
        private UserManager<ApplicationUser> _userManager;
        public PatchSetsController(ApplicationDbContext context, UserManager<ApplicationUser> mgr)
        {
            _context = context;
            _userManager = mgr;
        }

In a dotnetcore 1.0, EF7 application, add dbcontext in Startup.cs like so:

  services.AddEntityFramework().AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

(or, explicitly set to scoped lifetime)

Create a synchronous endpoint that executes a longer (~1s) query, and returns the result.

My controller has a method to run a long-running query and respond with the results as JSON. This calls .ToList() at the end of a LINQ query.

Specifically, my actual query is this:

List<PatchSet> patches  = _context.PatchSets.Include(c => c.Baseline).Include(c => c.Patches).ThenInclude(p => p.Patch).Where(c => c.Baseline.Id == currentPatchSet.Baseline.Id && c.Status == PatchSetStatus.Released).ToList();

Call this method, twice (via AJAX/xhr), with different parameters from the same page at nearly the same time.

Client logs show these requests occur within 1ms of eachother. Debugging shows that the operations occur concurrently.

The issue

The context appears to be shared between requests and causes some internal implementation errors (NPE, index out of range, etc) because both queries are running simultaneously.

If I use a mutex and lock around the query statement, the issue disappears entirely. The concurrent requests should be separate datacontexts, no?

  lock (locker)
            {
      patches  = _context.PatchSets.Include(c => c.Baseline).Include(c => c.Patches).ThenInclude(p => p.Patch).Where(c => c.Baseline.Id == currentPatchSet.Baseline.Id && c.Status == PatchSetStatus.Released).ToList();

            }            

The above code throws no exceptions at any time.

Further technical details

EF Core version: 1.0.0
Operating system: Windows 10
Visual Studio version: VS 2015

Other details about my project setup:

[mgallig]

The errors I am getting are a Null Pointer Error, and an Index Out of Range error, these appear randomly but fairly consistently.

Using a lock statement prevents these 100% of the time. These requests are on separate threads and separate XHR requests

[mgallig]

This appears to be fixed in 1.0.1, so this issue may be moot. I will report after further testing

[rowanmiller]

This looks like #5456 which was fixed in 1.0.1