Upgrade IdWeb Sidecar to .NET 10 (LTS)

[soodt]

Upgrade Sidecar from .NET 9 (EOL) to .NET 10 (LTS).

Description

.NET 9 reached end-of-life. This PR upgrades the Sidecar project to .NET 10 (LTS, supported until Nov 2028).

Changes

Version bump (3 files):

• Directory.Build.props: net9.0 → net10.0, SidecarAspDependencyVersion 9.0.9 → 10.0.0
• Dockerfile.AzureLinux: base image aspnet:9.0-azurelinux3.0-distroless → 10.0
• DockerFile.NanoServer: base image aspnet:9.0-nanoserver-ltsc2022 → 10.0
• Dockerfile: base images aspnet:9.0/sdk:9.0 → 10.0 (local/VS builds)

OpenAPI v2 breaking changes (2 files):

Microsoft.AspNetCore.OpenApi 10.0 ships with OpenAPI.NET v2, which has namespace and type changes:

• OpenApiDescriptions.cs: using Microsoft.OpenApi.Models → using Microsoft.OpenApi; Schema.Type changed from string to JsonSchemaType enum; added null guards for op.Parameters
• OptionsOverrideSchemaTransformer.cs: namespace update only
• Standardised AddAcquireTokenOption parameter order to match AddSimple (name, type, desc) — fixes a pre-existing bug where ForceRefresh had its description and type arguments silently swapped

Trimmer attribute restriction (1 file):

• Program.cs: .NET 10 disallows [RequiresUnreferencedCode]/[RequiresDynamicCode] on entry points (IL2123/IL3057). Added pragma suppression.

Test project update (1 file)

• Sidecar.Tests.csproj: net9.0 → net10.0, Microsoft.AspNetCore.Mvc.Testing 9.0.0 → 10.0.0

CI workflow fix (1 file)

• .github/workflows/dotnetcore.yml: Added SidecarEndpointsE2ETests exclusion to the net10.0 test step. These are E2E tests that require Azure AD lab credentials (client certificates in LocalMachine/My store) which are not available in GitHub Actions CI. The net9.0 test step already had this exclusion; the net10.0 step was missing it. The tests are also guarded by a #if !FROM_GITHUB_ACTION preprocessor directive, but the test filter is needed as an additional safeguard since the test assembly still gets discovered by dotnet test.

Testing

• ✅ dotnet publish succeeds targeting net10.0
• ✅ Docker image builds and starts (AzureLinux distroless)
• ✅ Health check: GET /healthz → 200
• ✅ Smoke test: GET /Validate with Bearer token → 200
• ✅ Load test: ~2000 req/s at 10 connections, all 2xx responses

[soodt]

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[soodt]

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[iNinja]

Good, clean upgrade. The OpenAPI.NET v2 breaking changes are handled correctly, and the ForceRefresh schema bug is a nice fix. One missed file is a blocker.

Dockerfile (lines 6 and 11) — blocking

The plain Dockerfile (used for local builds and Visual Studio) wasn't updated in this PR. Lines 6 and 11 still reference .NET 9:

dockerfile FROM mcr.microsoft.com/dotnet/aspnet:9.0 AS base FROM mcr.microsoft.com/dotnet/sdk:9.0 AS build

After this merges, docker build locally or building via VS will produce a .NET 9 image while the project targets net10.0. Both references need bumping to 10.0.

[Copilot]

Pull request overview

This PR upgrades the Microsoft.Identity.Web Sidecar project and its E2E tests from .NET 9 to .NET 10 (LTS), aligning the Sidecar’s runtime, dependencies, and container images with the supported platform baseline.

Changes:

• Bumped Sidecar and Sidecar E2E tests to net10.0, and updated ASP.NET Core dependency versions to 10.0.0.
• Updated Sidecar OpenAPI helpers to accommodate OpenAPI.NET v2 API/namespace changes (e.g., JsonSchemaType).
• Updated Sidecar Docker base images to ASP.NET Core 10.0 and suppressed new .NET 10 entry-point trim-analyzer restrictions via pragmas.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/E2E Tests/Sidecar.Tests/Sidecar.Tests.csproj	Moves Sidecar E2E tests to net10.0 and updates Microsoft.AspNetCore.Mvc.Testing to 10.0.0.
src/Microsoft.Identity.Web.Sidecar/Program.cs	Adds analyzer warning suppressions for .NET 10 entry-point attribute restrictions.
src/Microsoft.Identity.Web.Sidecar/OptionsOverrideSchemaTransformer.cs	Updates OpenAPI namespace import for OpenAPI.NET v2 compatibility.
src/Microsoft.Identity.Web.Sidecar/OpenApiDescriptions.cs	Updates OpenAPI schema typing to JsonSchemaType and adds parameter null guards.
src/Microsoft.Identity.Web.Sidecar/DockerFile.NanoServer	Updates NanoServer ASP.NET runtime base image from 9.0 to 10.0.
src/Microsoft.Identity.Web.Sidecar/Dockerfile.AzureLinux	Updates AzureLinux distroless ASP.NET runtime base image from 9.0 to 10.0.
src/Microsoft.Identity.Web.Sidecar/Directory.Build.props	Updates Sidecar TFM to net10.0 and bumps Sidecar ASP.NET dependency version to 10.0.0.

[iarekk]

LGTM 👍