Skip to main content

.NET 8– Upgrade warnings

As our policy is to keep our .NET applications on the latest LTS version, we started to upgrade our application portfolio to .NET 8. Changing the Target Framework Moniker and updating the ASP.NET Core NuGet packages was sufficient to get the upgrade done.  However the upgrade also triggered some warnings and because we had ‘Treat warnings as errors’ enabled in Visual Studio, our applications refused to compile.

SYSLIB0051

The first warning we got was SYSLIB0051:

Severity

Code

Description

Project

File

Line

Suppression State

Warning

SYSLIB0051

'Exception.Exception(SerializationInfo, StreamingContext)' is obsolete: 'This API supports obsolete formatter-based serialization. It should not be called or extended by application code.'

SOFACore

C:\source\repos\SOFACore\Configuration\ConfigurationException.cs

20

Active

For every exception class we had a specific constructor that was only used for serialization purposes. As this constructor was intended to support remoting and remoting is not supported in .NET Core it doesn’t make sense to keep this constructor.

We got rid of this warning by removing all the serialization constructors for our Exception classes.

SYSLIB0049

A second (less frequent) warning we got SYSLIB0049:

Severity

Code

Description

Project

File

Line

Suppression State

Warning

SYSLIB0049

'JsonSerializerOptions.AddContext<TContext>()' is obsolete: 'JsonSerializerOptions.AddContext is obsolete. To register a JsonSerializerContext, use either the TypeInfoResolver or TypeInfoResolverChain properties.'

eShopExample

C:\source\repos\SOFACore\Example\eShopExample\Startup.cs

55

Active

In our code we use a custom JsonContext to configure how serialization should be handled by System.Text.Json:

The JsonSerializerOptions.AddContext<TContext>() method was introduced in .NET 6 as a means to associate JsonSerializerOptions instances with a specified JsonSerializerContext type. This method was superseded in .NET 7 with the introduction of contract customization and the TypeInfoResolver property.

As the JsonSerializerContext type implements the ITypeInfoResolver interface , we can easily get rid of this warn by updating our code like this:

In the code above the JsonContext class is our own implemented JsonSerializerContext:

Labels:

Popular posts from this blog

Podman– Command execution failed with exit code 125

After updating WSL on one of the developer machines, Podman failed to work. When we took a look through Podman Desktop, we noticed that Podman had stopped running and returned the following error message: Error: Command execution failed with exit code 125 Here are the steps we tried to fix the issue: We started by running podman info to get some extra details on what could be wrong: >podman info OS: windows/amd64 provider: wsl version: 5.3.1 Cannot connect to Podman. Please verify your connection to the Linux system using `podman system connection list`, or try `podman machine init` and `podman machine start` to manage a new Linux VM Error: unable to connect to Podman socket: failed to connect: dial tcp 127.0.0.1:2655: connectex: No connection could be made because the target machine actively refused it. That makes sense as the podman VM was not running. Let’s check the VM: >podman machine list NAME         ...
Read more

Cache stampede: when our cache turned against us

While investigating some performance issues, we ran into an ASP.NET Core API that cached a fairly expensive aggregation query for 60 seconds. Under normal load, that was fine: one request rebuilds the cache, everyone else reads from it. Under peak load, dozens of requests would arrive in that same expiry window, all see a cache miss, and all fire the same expensive query in parallel. The database didn't like that. That was the moment when our caching layer stopped helping and started hurting. A burst of requests comes in at the same time, all miss the cache, and all go hammer the database or the downstream API at once. That's a cache stampede . The cache was supposed to protect our backend, and for a few hundred milliseconds it did the opposite. Why this happens IMemoryCache.GetOrCreate (and its async sibling) looks like it protects you, but it doesn't add any locking on its own. Look at the naive version: public async Task<Report> GetReportAsync(string key) ...
Read more

A complex system designed from scratch never works

A few years ago, I worked as an architect on a big mainframe rewrite. I still count it as one of my failures. Not because the technology was wrong, but because I couldn't convince the management team to simplify the approach. Years later, the organization is still struggling to get the new system up and running. I left the project at the time, because I couldn't put my name behind an approach that would take very long and cost a lot of money without a working system to show for it along the way. Gall’s Law That memory keeps coming back to me, because it's a textbook case of Gall's Law playing out in real life. Gall's Law , from John Gall's Systemantics , states it plainly: A complex system that works is invariably found to have evolved from a simple system that worked. A complex system designed from scratch never works, and it cannot be patched to make it work. You have to start over with a simple system that works. What does that mean in practice,...
Read more