A new wave of analyzers in .NET 8

[giscus[bot]]

A new wave of analyzers in .NET 8

Analyzers did become an integral part of the .NET ecosystem. Their main responsibility is to find potential code issues and warn you. Often times this comes even with potential fixes you can directly apply.
And Microsoft will continue this journey with the upcoming .NET 8 release. This blog post will show you potential candidates, which will make the cut.

https://steven-giesel.com/blogPost/1a03a998-e428-4a42-9c30-1cfbf6ac5f4c

[ndepend]

Concerning the ToLower() stuff, there is also a trap with special characters like the Turkish I we stumbled upon once with a Turkish user
https://haacked.com/archive/2012/07/05/turkish-i-problem-and-why-you-should-care.aspx/

[linkdotnet]

Yes that's true.ToLowerInvariant and its brother ToUpperInvariant don't suffer from the Turkish "i" problem, but still would be flagged by the compiler as you still create a new string.

[darthwalsh]

The Any() rule feels like a micro-optimization. If I was considering that, I might also consider migrating that performance-critical code to C++ or Rust.
(BTW, I think the GitHub link for that rule isn't correct.)

[linkdotnet]

My best guess why Any is not inline-able, is because of this:

using (IEnumerator<TSource> e = source.GetEnumerator()) 

Taken from here. using is basically a try-finally block. Any try block can't be inlined.

Anyway, I also never saw that Any would lead to such side-effects as described (where I am also not 100% sure, if I really understand the statement). As we are still in the alpha-phase of .NET 8, everything can change.

[kaspervandenberg]

Would it be possible to short circuit Any() with Length != 0 (or Count != 0) for (commonly used) types of enumerable that support it? (Ofcourse without checking the type of container at runtime. Currently I don't know if extension methods support overloading.)

[linkdotnet]

Any is an extension method so that should work...given the fact that there are already overloaded versions of Any. Good point @kaspervandenberg

[JustDre]

.NET 6 added TryGetNonEnumeratedCount, which is used in .Any(). https://github.com/dotnet/runtime/blob/main/src/libraries/System.Linq/src/System/Linq/AnyAll.cs

But as mentioned, the entire method cannot be inlined, either because of the using or else because it's too long. I've verified in SharpLab that an extension method such as the following does indeed get inlined:

public static bool HasAny<T>(this List<T> list) => list.Count != 0;

[linkdotnet]

Hmm good to know and thanks for the analysis @JustDre

I am inclined to do so some performance tests/benchmarks in the upcoming days. I am just interested in what this analyzer suggestion means in numbers. Anyway, it is only flagged as "info" as of now.

[Caltor]

I realise it's not the point of the article but I think the logic for these two lines is inverted:

var isEmpty = names.Any();
var isEmpty = names.Count != 0;

I think it should be:

var isEmpty = !names.Any();
var isEmpty = names.Count == 0;

Or rename isEmpty to something more suitable.

[linkdotnet]

Hey @Caltor , you are absolutely right! Spot on and thanks for reporting! Fixed

[DrGriff]

Regarding .Any() vs .Count != 0. If my collection contained 1 million items, then would it not need to iterate the whole collection to calculate .Count, whereas .Any() would stop executing as soon as it found the first item?

[linkdotnet]

It really depends on your underlying collection. Let's say you have a List or Array then Count is just a property that is "constantly updated" when you add or delete items. So no one has to go through your items to check, as this information is available in constant time (O(1) in big O notation).

Any has also some shortcuts if it detects that the underlying type is a List, Array (and everything that is materialized). If so, it just checks Count != 0.

The picture shifts if you have something like IEnumerable<T>. Here Any() just has to check one single entry to return true or false. But you might notice that IEnumerable doesn't offer a Count or Length property - as this information would require to go through the whole enumeration. If the underlying collection is a database, that might be a huge impact to your application.

That is why the given analyzer is only checking for types that are already materialized (List, Array and friends).

I hope that answers your question.

[fseidl-bauradar]

A little bit of the toppic, but I waiting for a new solution how to retrieve the HttpContext over the DI outside the Controllers after the IHttpContextAccessor is no longer available

[linkdotnet]

Nono - not the NuGet package. That has nothing to do with any external dependency.

The package you are referring was a "polyfill" prior to .net core 3.
This:

<ItemGroup>
    <FrameworkReference Include="Microsoft.AspNetCore.App" />
</ItemGroup>

Has nothing to do with NuGet directly. Depending on your Target Framework, you reference those assemblies implicitly.

So to sum it up, there are two ways to access your IHttpContextAccessor without any Nuget package:

1. Use the <Project Sdk="Microsoft.NET.Sdk.Web"> SDK type - aka you create a web application. Then you can easily call: builder.Services.AddHttpContextAccessor() and use the interface.
2. Or if you are in a library project, use the <FrameworkReference Include="Microsoft.AspNetCore.App" /> part.

[linkdotnet]

When you install the .NET SDK locally you are also installing assemblies for ASP.NET (which includes IHttpContextAccessor).
And these will be added by either of the things shown above

[fseidl-bauradar]

Sounds a little bit fishy for me, replacing a deprecated Package with a deprecated Package with security holes in addition.

[linkdotnet]

That has nothing to do with the provided nuget packages you have shown.

There are old relicts from prior .net core 3 /.netstandard2.0. That is why they aren't supported anymore.
The things I did showcase here have nothing to do with that. Yes they have the same name - so that the API is stable, but that is it.

IHttpContextAccessor is very much alive and widely used.

Here the official documentation: https://learn.microsoft.com/en-us/aspnet/core/fundamentals/target-aspnetcore?view=aspnetcore-8.0&tabs=visual-studio#use-the-aspnet-core-shared-framework

Be advised this is for net 8 - so very much alive and supported.

[fseidl-bauradar]

Thanks you for the Link, so I looking for a solution how to get ride of this Package since months now, seems that replacement.