Move FwLite and Lexbox to .NET 10

[rmunn]

Fixes #2227.
Fixes #2228.

Currently fails to compile with a single "extension method is ambiguous" error on AsyncEnumerable.ToArrayAsync. Opening a PR anyway so that I can get an AI code review, which might help inform me of the C# syntax I need to disambiguate these (since I don't know that particular syntax off the top of my head).

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📝 Walkthrough

Walkthrough

This PR upgrades the entire project from .NET SDK 9.x to 10.x. Changes are applied uniformly across global build properties, project target frameworks, CI/CD workflows, Docker base images, VS Code debug configurations, build automation tasks, and documentation to maintain consistency across all development and deployment pathways.

Changes

.NET 10 Upgrade

Layer / File(s)	Summary
Global Build Configuration global.json, backend/Directory.Build.props	SDK version pinned to 10.0.100; default target framework set to net10.0 when not explicitly specified.
Project Target Frameworks backend/WebServiceDefaults/WebServiceDefaults.csproj, backend/FwLite/FwLiteMaui/FwLiteMaui.csproj, backend/FwLite/FwLiteMaui.Tests/FwLiteMaui.Tests.csproj	TargetFramework and TargetFrameworks updated to net10.0 and net10.0-* platform variants (Android, iOS, macCatalyst, Windows).
CI/CD Pipeline Configuration .github/workflows/fw-lite.yaml, .github/workflows/integration-test-gha.yaml, .github/workflows/integration-test.yaml, .github/workflows/lexbox-api.yaml, .github/workflows/lexbox-fw-headless.yaml	All actions/setup-dotnet steps updated to use dotnet-version: '10.x'; publish targets for Android and Windows MAUI updated to net10.0-android and net10.0-windows10.0.19041.0.
Container Build Images backend/Dockerfile, backend/FwHeadless/Dockerfile, backend/FwHeadless/dev.Dockerfile, backend/FwLite/FwLiteWeb/Dockerfile, backend/LexBoxApi/dev.Dockerfile	Docker base and build stages upgraded to .NET 10.0 SDK and ASP.NET runtime images.
Developer Environment Configuration .vscode/launch.json, .vscode/tasks.json	Launch configuration program paths and build task --framework arguments updated to reference net10.0 debug outputs.
Build and Test Task Configuration backend/FwLite/Taskfile.yml	MAUI Windows/Android build and publish tasks, along with test-verified command, updated to target net10.0 frameworks.
Documentation Updates AGENTS.md, backend/AGENTS.md, backend/FwLite/AGENTS.md, backend/FwLite/README.md	All version references and example build commands updated from .NET 9 to .NET 10.

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Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

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Possibly related PRs

• sillsdev/languageforge-lexbox#2005: Concurrent updates to .github/workflows/fw-lite.yaml for Windows SDK and .NET version configuration.
• sillsdev/languageforge-lexbox#2020: Updates to .vscode/launch.json and .vscode/tasks.json for FwHeadless and Lexbox debug/build configuration.

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Suggested labels

📦 Lexbox

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Suggested reviewers

• josephmyers
• myieye

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Poem

🐰 From nine to ten, the version grows,
With dotnet SDK that swiftly flows,
Through workflows, configs, Dockerfiles too,
Each framework target shines anew! ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'Move FwLite and Lexbox to .NET 10' directly and clearly summarizes the primary change in the changeset, which updates multiple projects and configuration files from .NET 9 to .NET 10.
Description check	✅ Passed	The description references fixing issues #2227 and #2228, which align with the changeset's objective to update FwLite and Lexbox to .NET 10, and mentions a compilation error encountered during the migration.
Linked Issues check	✅ Passed	The code changes comprehensively update FwLite and Lexbox to .NET 10 across all relevant files (workflows, Dockerfiles, project files, documentation), addressing the core requirements of issues #2227 and #2228.
Out of Scope Changes check	✅ Passed	All changes in the pull request are directly related to the .NET 10 migration; no unrelated modifications to other features, dependencies, or functionality are present.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/dotnet-10

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[github-actions]

C# Unit Tests

165 tests   165 ✅  19s ⏱️
 23 suites    0 💤
  1 files      0 ❌

Results for commit b529aa3.

♻️ This comment has been updated with latest results.

[github-actions]

UI unit Tests

  1 files   59 suites   31s ⏱️
176 tests 176 ✅ 0 💤 0 ❌
245 runs  245 ✅ 0 💤 0 ❌

Results for commit b529aa3.

♻️ This comment has been updated with latest results.

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Build	Status	Details	Updated (UTC)
default (Inspect)	✅ No changes detected	-	May 11, 2026, 9:00 AM

[rmunn]

@coderabbitai Can you recommend how to deal with the five "The call is ambiguous between the following methods or properties" errors on the five uses of .ToArrayAsync() in MiniLcmApiExtensions.cs?

[coderabbitai]

Tip

For best results, initiate chat on the files or code changes.

🧩 Analysis chain

Let me look at the file in question to give a precise recommendation.

---

🏁 Script executed:

#!/bin/bash
fd "MiniLcmApiExtensions.cs" --exec cat {}

Length of output: 729

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Now let me check the project file and package references to pinpoint the conflict.

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🏁 Script executed:

#!/bin/bash
# Find the .csproj that contains MiniLcmApiExtensions.cs
fd "MiniLcmApiExtensions.cs" --exec echo "File: {}"
# Find MiniLcm project files
fd "MiniLcm.csproj" --exec cat {}
# Check for System.Linq.Async references across the solution
rg "System\.Linq\.Async" --type xml -n

Length of output: 917

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Now I have a clear picture of the root cause. Let me confirm the .NET 10 migration guidance.

@rmunn The root cause is a known .NET 10 breaking change. .NET 10 introduces the AsyncEnumerable class with a full set of LINQ extension methods for IAsyncEnumerable<T>, and this replaces the community-maintained System.Linq.Async NuGet library, potentially causing compilation errors due to ambiguities.

Your MiniLcm.csproj has a direct <PackageReference Include="System.Linq.Async" />, so both sources now provide ToArrayAsync with identical signatures — hence the five CS0121 errors.

Recommended fix: If you're upgrading to .NET 10 and your code includes a direct package reference to System.Linq.Async, remove that package reference or upgrade to version 7.0.0.

Since MiniLcm only targets net10.0 (not multi-targeting), the cleanest solution is to simply remove the package reference from backend/FwLite/MiniLcm/MiniLcm.csproj:

-    <PackageReference Include="System.Linq.Async" />

The five ToArrayAsync() calls in MiniLcmApiExtensions.cs will then resolve unambiguously to the BCL's System.Linq.AsyncEnumerable.ToArrayAsync.

One caveat: Check whether any other code in the MiniLcm project (or projects that depend on it) uses Ix.NET-specific operators like SelectAwait, WhereAwait, AnyAwaitAsync, etc. If you were relying on functionality from System.Linq.Async that has not been implemented in the new System.Linq.AsyncEnumerable, you will need to add a reference to the Ix.NET project's System.Interactive.Async package, which is the new home for these features. Given that your current code only uses plain ToArrayAsync, you are most likely safe to remove it outright.

[rmunn]

See https://endjin.com/blog/ix-v7-dotnet-10-linq-iasyncenumerable (linked from https://learn.microsoft.com/en-us/dotnet/core/compatibility/core-libraries/10.0/asyncenumerable) for more details on the transition.

[rmunn]

First run of dotnet test got timed out after running for 40 minutes. Is that normal? Or did moving from .NET 9 to .NET 10 slow things down significantly? I don't remember it taking that long to run the tests before the move...

[rmunn]

It was just the build runner getting stuck. Maybe yet another Azure hiccup behind the scenes. Rerunning the tests succeeded in 13 minutes.

[myieye]

@rmunn I've seen that about 5 times.
So, sadly it's somewhat recurrent, but thankfully only rarely.

[myieye]

🥳
Looks good to me.
It'd definitely be good to bump and cleanup nugets after this.