[solrevdev]

What changed

• src/Ytx/Ytx.csproj and tests/Ytx.Tests/Ytx.Tests.csproj always target net10.0 and add net11.0 when the SDK is 11 or later:

  <TargetFrameworks>net10.0</TargetFrameworks>
  <TargetFrameworks Condition="$([MSBuild]::VersionGreaterThanOrEquals('$(NETCoreSdkVersion)', '11.0'))">net10.0;net11.0</TargetFrameworks>

• New global.json: { "sdk": { "version": "10.0.100", "rollForward": "latestMajor", "allowPrerelease": false } }.
• .github/workflows/publish.yml: both setup-dotnet steps install 10.0.x and 11.0.x only. They list explicit versions and do not use global-json-file, so the new global.json does not reduce them to one SDK. global.json is not in the path filters on purpose, so a build-setting change alone does not publish.
• .github/workflows/publish.yml: a "Check package targets" step after Pack in both the validate and publish jobs, matching bbx. It fails the run unless the nupkg holds tools/net10.0/any/Ytx.dll and tools/net11.0/any/Ytx.dll. It also requires exactly one package in nupkg/, because unzip -l reads a second path as a member name. codeql.yml uses build-mode: none and sets up no SDK, so it needed no change.
• README.md (new "SDK policy" section), AGENTS.md and .github/copilot-instructions.md describe the SDK policy and name .NET 10 and 11 only.
• CHANGELOG.md: a Breaking entry under Unreleased.

Why

John decided on 11 Nov 2026 that tools and tests follow supported .NET versions only. .NET 8 and 9 left support on 10 Nov 2026, so nothing targets them now.

SDK policy

.NET 10 is the LTS and the baseline.

• With only SDK 11, the project builds and works.
• With SDKs 10 and 11, latestMajor picks 11 and both targets build.
• With only SDK 10, the project still builds and works, for net10.0 only.
• CI installs both SDKs, so the published package ships net10.0 and net11.0. A package packed on SDK 10 alone would hold net10.0 only. The new CI check fails the run in that case, so such a package cannot be published.

<RollForward>Major</RollForward> is already in the csproj since e6f0b16. This PR does not add it again.

Install compatibility

Dropping net8.0 and net9.0 means a machine with only .NET 8 or 9 can no longer install new releases. It needs the .NET 10 or 11 runtime. Older versions stay on NuGet.

Versioning and release

CI owns <Version>, so this PR does not bump it by hand. A normal merge to master triggers publish.yml, which does a patch bump (1.2.2) and publishes to NuGet. To ship this as the minor release it should be (1.3.0), merge with [skip ci] in the merge commit subject, then run "Publish NuGet (ytx)" manually with bump: minor. Merging and releasing is John's call.

Proof (local, macOS, SDKs 10.0.404 and 11.0.100, runtimes 10.0.15 and 11.0.0)

Packs used -p:Version=1.3.0 to match the planned minor bump. Installs went to scratch tool paths. The global install was not touched.

(a) Normal run, repo global.json

dotnet --version: 11.0.100
dotnet build src/Ytx -c Release
  Ytx -> .../bin/Release/net10.0/Ytx.dll
  Ytx -> .../bin/Release/net11.0/Ytx.dll
  0 Warning(s), 0 Error(s)
dotnet test -f net10.0: Passed!  - Failed: 0, Passed: 145, Skipped: 0, Total: 145
dotnet test -f net11.0: Passed!  - Failed: 0, Passed: 145, Skipped: 0, Total: 145
unzip -l solrevdev.ytx.1.3.0.nupkg: tools/net10.0/, tools/net11.0/

(b) SDK 10 only (scratch copy, global.json pinned to 10.0.404 with rollForward: disable, not committed)

dotnet --version: 10.0.404
dotnet build src/Ytx -c Release
  Ytx -> .../bin/Release/net10.0/Ytx.dll
  0 Warning(s), 0 Error(s)
bin/Release: net10.0 (tool and tests)
dotnet test: Passed!  - Failed: 0, Passed: 145, Skipped: 0, Total: 145 (net10.0)
unzip -l solrevdev.ytx.1.3.0.nupkg: tools/net10.0/
ytx --version: ytx 1.3.0

(c) Install the package from (a)

dotnet tool install --tool-path <scratch>/tools --add-source <scratch>/nupkg solrevdev.ytx --version 1.3.0
Tool 'solrevdev.ytx' (version '1.3.0') was successfully installed.
installed tools/: net10.0, net11.0
ytx --version: ytx 1.3.0

(d) Package target check, run locally with the step's exact script

SDK 11 pack (dotnet --version 11.0.100, tools/net10.0 and tools/net11.0):
exit=0

SDK-10-only pack from (b) (tools/net10.0 only):
Package is missing tools/net11.0
exit=1

Folder with two old packages: "Expected one package in .../nupkg, found: ...1.0.4.nupkg ...1.0.5.nupkg", exit=1
Empty folder: "Expected one package ...", exit=1

🤖 Generated with Claude Code

https://claude.ai/code/session_014Mjr3bTLWVmY8sc2j5bcqH