Add SDK analyzer assembly redirector #80969

jjonescz · 2025-10-31T13:27:11Z

Moved here from the SDK per David Kean's request (to avoid another assembly load). Originally lived here:

Validation: ~~https://dev.azure.com/devdiv/DevDiv/_git/VS/pullrequest/684831~~ ~~https://dev.azure.com/devdiv/DevDiv/_git/VS/pullrequest/696938~~
https://dev.azure.com/devdiv/DevDiv/_git/VS/pullrequest/699576

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

jjonescz · 2025-12-02T10:24:10Z

@jasonmalinowski for another look, thanks

This reverts commit 67e5b88.

jasonmalinowski · 2025-12-18T22:13:08Z

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

+        var enable = Environment.GetEnvironmentVariable("DOTNET_ANALYZER_REDIRECTING");
+        _enabled = !"0".Equals(enable, StringComparison.OrdinalIgnoreCase) && !"false".Equals(enable, StringComparison.OrdinalIgnoreCase);


Should this be using VS feature flags or a user setting or something else? We don't usually use enviornment variables much if we can since we have other mechanisms.

It's also a bit weird that setting these environment variables would break tests. If we were going to keep it, I'd expect that was read at the non-unit derived type.

Good point, I'm not familiar with VS feature flags, I guess that's a bit complicated to add one? Is there an example or docs how to add new one? I just wanted a way to opt out if necessary, but originally I didn't even have that and I think that might be fine too.

Feature flags would be for if you wanted to support a rollback more generally, or you were trying to A/B test this or something. If you just wanted a setting, then this could be a user setting. You'd add that setting to our unified settings registration (maybe there's a way to hide it though?) and follow what #81503 added.

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

jasonmalinowski · 2025-12-18T22:20:00Z

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

+                if (!analyzerPath.StartsWith(topLevelDirectory, StringComparison.OrdinalIgnoreCase))
+                {
+                    continue;
+                }


How would this happen? Or just a paranoia check?

I guess the latter, I will add an assert.

Use Debug.Fail() here, so you can add a message or something. And add a comment. We normally don't use asserts much on the IDE side, but given a throw here might really break things (i.e. no analyzers added for you!), it's probably appropriate here.

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

jasonmalinowski · 2025-12-18T22:22:31Z

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

+                }
+
+                var subsetName = Path.GetFileName(topLevelDirectory);
+                if (!versions.TryGetValue(subsetName, out var version))


It'd be nice if there was a comment what the versions JSON is or looks like. There's not a file I can look at right now so I'm guessing, but I would have assumed versioning was related to the individual DLL which is odd since this path isn't depending on that yet....

There is an example in the doc (which is linked in the doc comment of SdkAnalyzerAssemblyRedirector): https://github.com/dotnet/sdk/blob/main/documentation/general/analyzer-redirecting.md

Ah that's really helpful. How does versioning work in this design them? If we needed to have redirected versions for a 9.0 and 10.0, then there'd be two top level folders in the JSON with different names?

If we needed to have redirected versions for a 9.0 and 10.0

That's intentionally unsupported. There is always only one SDK version inserted into VS anyway.

then there'd be two top level folders in the JSON with different names?

I guess that would technically work. I will add a test. But that won't happen in the way we currently generate the payload in the sdk repo.

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

jasonmalinowski

Looks good. Wouldn't mind a few more tests around "very" unexpected path cases just to make sure we don't trip up on those. For example, you have lots of tests for when the paths look "about right", but would the path mapping code get messed up where the suffix does match, but that's the root of the drive? Or just C:\AnalyzerName.dll? We've had bugs like that in the past.

jasonmalinowski · 2025-12-20T00:31:18Z

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

+                if (!analyzerPath.StartsWith(topLevelDirectory, StringComparison.OrdinalIgnoreCase))
+                {
+                    continue;
+                }


Use Debug.Fail() here, so you can add a message or something. And add a comment. We normally don't use asserts much on the IDE side, but given a throw here might really break things (i.e. no analyzers added for you!), it's probably appropriate here.

jasonmalinowski · 2025-12-20T00:32:31Z

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

+                }
+
+                var subsetName = Path.GetFileName(topLevelDirectory);
+                if (!versions.TryGetValue(subsetName, out var version))


Ah that's really helpful. How does versioning work in this design them? If we needed to have redirected versions for a 9.0 and 10.0, then there'd be two top level folders in the JSON with different names?

jasonmalinowski · 2025-12-20T00:33:10Z

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

+        var enable = Environment.GetEnvironmentVariable("DOTNET_ANALYZER_REDIRECTING");
+        if (!"0".Equals(enable, StringComparison.OrdinalIgnoreCase) && !"false".Equals(enable, StringComparison.OrdinalIgnoreCase))
+        {
+            return Path.GetFullPath(Path.Combine(AppDomain.CurrentDomain.BaseDirectory, @"CommonExtensions\Microsoft\DotNet"));


Should this check if the folder is present first? Or we're trusting that nothing will try to use it before the File.Exists check doesn't find the metadata.json?

we're trusting that nothing will try to use it before the File.Exists check doesn't find the metadata.json

Yes, in the current implementation, the directory path is not even stored anywhere else, so that File.Exists check should be enough I think.

jasonmalinowski · 2025-12-20T00:36:16Z

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

+                return false;
+            }
+
+            var directoryPathVersion = Path.GetFileName(Path.GetDirectoryName(directoryPath.Substring(0, index)));


Make sure there's a test if somebody were to add a reference to Z:\analyzers\dotnet\Foo.dll or wherever, where the suffix does match but there is no parent directory.

If the suffix matches, that's enough and it will be redirected, there is no need for it to have a parent directory. But I can add a test for it, thanks.

davkean · 2025-12-23T03:05:38Z

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

+        //                                     ~~~~~~~~~~~~~~~~~~~~~~~                                                     = topLevelDirectory
+        //                                                             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ = analyzerPath
+
+        foreach (var topLevelDirectory in Directory.EnumerateDirectories(insertedAnalyzersDirectory))


Is there a way we can produce a file that produces all this up front so we don't need to search for binaries that ship in the product? This is having the user pay a cost for things we can absolutely determine because we insert these binaries.

Yes, sounds doable, I will look into that, thanks.

Done in 64ed67b with SDK counterpart in dotnet/sdk#52326.

jjonescz · 2026-01-09T09:43:36Z

@jasonmalinowski can you please take another look? I made some changes since your last sign off. Thanks.

src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs

jjonescz · 2026-01-12T11:05:52Z

/pr-val

github-actions · 2026-01-12T11:06:32Z

View PR Validation Run triggered by @jjonescz

Parameters

Validation Type: pr-val
Pipeline ID: 8972
Pipeline Version: main
PR Number: 80969
Commit SHA: 9a8b74832021739c44150a5cdfe255016d3f8e59
Source Branch: analyzer-redirecting
Target Branch: main
Build ID: 13078718

Add SDK analyzer assembly redirector

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github-actions bot added the Area-IDE label Oct 31, 2025

jjonescz mentioned this pull request Oct 31, 2025

Remove analyzer redirecting DLL dotnet/sdk#51511

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jjonescz marked this pull request as ready for review November 5, 2025 13:24

jjonescz requested a review from a team as a code owner November 5, 2025 13:24

jjonescz requested review from 333fred and JoeRobich November 5, 2025 13:25

jasonmalinowski reviewed Nov 6, 2025

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jasonmalinowski reviewed Nov 6, 2025

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src/VisualStudio/Core/Def/ProjectSystem/SdkAnalyzerAssemblyRedirector.cs Outdated Show resolved Hide resolved

Extract class for testing

ada02f5

jjonescz requested a review from jasonmalinowski November 11, 2025 10:39

jjonescz added 3 commits December 17, 2025 16:30

Log asynchronously

67e5b88

Revert "Log asynchronously"

4d41781

This reverts commit 67e5b88.

Fix GetService call

188e55d

jasonmalinowski reviewed Dec 18, 2025

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Improve code

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jjonescz requested a review from jasonmalinowski December 19, 2025 14:39

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Improve code and tests

68e5ea8

davkean reviewed Dec 23, 2025

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jjonescz mentioned this pull request Jan 6, 2026

Include all file paths in analyzer redirecting metadata file dotnet/sdk#52326

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Obtain analyzer files from metadata

64ed67b

JoeRobich reviewed Jan 9, 2026

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Fix version comparsion logic

9a8b748

jjonescz merged commit bba5b13 into dotnet:main Jan 13, 2026
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jjonescz deleted the analyzer-redirecting branch January 13, 2026 09:32

dotnet-policy-service bot added this to the Next milestone Jan 13, 2026

		var enable = Environment.GetEnvironmentVariable("DOTNET_ANALYZER_REDIRECTING");
		_enabled = !"0".Equals(enable, StringComparison.OrdinalIgnoreCase) && !"false".Equals(enable, StringComparison.OrdinalIgnoreCase);

Add SDK analyzer assembly redirector #80969

Add SDK analyzer assembly redirector #80969

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