update-roslyn

name	update-roslyn
description	Update the Roslyn version used by this repo — bump package versions in Directory.Build.props / Directory.Packages.props, correlate the private-feed version by commit ID, sync the vendor/roslyn submodule to the same commit, then build, test, and run Morgania and RoslynPad and fix fallout. Use when asked to update/bump Roslyn or the Roslyn submodule.

Updating the Roslyn version

Three things must stay in sync, all pointing at the same Roslyn commit:

1. RoslynVersion in Directory.Packages.props — the public Microsoft.CodeAnalysis.* packages from nuget.org.
2. RoslynPrivateVersion in Directory.Packages.props — Microsoft.CodeAnalysis.LanguageServer.Protocol and Microsoft.CodeAnalysis.Remote.Workspaces from the dnceng dotnet-tools feed (not published to nuget.org). Consumed only by src/RestoreHelper/RestoreHelper.csproj, which pulls their DLLs for direct reference.
3. The vendor/roslyn submodule — its src/EditorFeatures/{Text,Core,CSharp} sources are recompiled by src/Morgania.CodeAnalysis.EditorFeatures against the public packages, so source/binary API drift breaks the build.

Step 1 — Bump versions in props files

• Directory.Build.props: update the <Version> property (the NuGet version the Morgania packages ship as).
• Directory.Packages.props: update <RoslynVersion> to the new public version.

Step 2 — Find the matching private version

The public and private packages both end their nuspec <description> with https://github.com/dotnet/roslyn/commit/<sha>. Correlate on that SHA.

Get the public package's commit:

curl -sL "https://api.nuget.org/v3-flatcontainer/microsoft.codeanalysis.common/$ROSLYN_VERSION/microsoft.codeanalysis.common.nuspec" \
  | grep -o 'commit/[0-9a-f]*'

List candidate private versions (feed is anonymously readable; also browsable at https://dev.azure.com/dnceng/public/_artifacts/feed/dotnet-tools/NuGet/Microsoft.CodeAnalysis.LanguageServer.Protocol/):

curl -sL "https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-tools/nuget/v3/flat2/microsoft.codeanalysis.languageserver.protocol/index.json" \
  | python3 -c "import json,sys; [print(v) for v in json.load(sys.stdin)['versions'] if v.startswith('$ROSLYN_VERSION-')]"

There are many prefix matches (e.g. 5.3.0-2.26078.5 for public 5.3.0), and multiple branches publish builds with the same version prefix — don't assume the newest matches. Narrow by date: the build number encodes an Arcade "short date" (yy*1000 + mm*50 + dd, so 2.26263.10 = 2026-05-13). Get the public commit's date (git -C vendor/roslyn show -s --format=%ci <sha>) and probe builds from that day and the days right after:

curl -sL "https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-tools/nuget/v3/flat2/microsoft.codeanalysis.languageserver.protocol/$CANDIDATE/microsoft.codeanalysis.languageserver.protocol.nuspec" \
  | grep -o 'commit/[0-9a-f]*'

Set <RoslynPrivateVersion> in Directory.Packages.props to the matching version.

Step 3 — Update the roslyn submodule

Check out the same commit SHA found in step 2 (check first — it may already be there):

git -C vendor/roslyn fetch origin <sha>
git -C vendor/roslyn checkout <sha>

The submodule pointer change gets committed with the rest of the update.

Step 4 — Clean, build, test, run, fix

Clean first — this is not optional. IgnoresAccessChecksToGenerator caches the publicized copies of the Roslyn assemblies under obj/**/IgnoresAccessChecksToGenerator/, and its incremental up-to-date check will happily keep serving assemblies publicized from the old Roslyn version. Stale leftovers produce baffling errors (missing internal types, missing namespaces, CS1069 type-forward failures) that look like API drift but aren't. Delete all bin/obj before the first build:

find src tests -type d \( -name obj -o -name bin \) -prune -exec rm -rf {} +

SDK is pinned by global.json.

dotnet build RoslynPad.slnx
dotnet test RoslynPad.slnx

If the first post-clean build shows errors in downstream projects (e.g. Morgania.CodeAnalysis.Editor), rebuild once before investigating — errors from a build where an upstream project was still broken can be stale-state artifacts that vanish on the next pass.

Then run both apps and smoke-test editor features (completion, quick info, signature help, diagnostics/squiggles, rename, formatting; in RoslynPad also NuGet resolution and script execution):

• src/Morgania.Demo.EditorFeatures (and src/Morgania.Demo) — the Morgania editor
• src/RoslynPad — the RoslynPad app

Fixing fallout

Most breakage comes from recompiling the new vendored sources:

• Missing/changed APIs in vendored EditorFeatures code — fix in src/Morgania.CodeAnalysis.EditorFeatures/Shims and Stubs, or add the file to the <Compile Remove> list in the csproj if the feature is intentionally excluded (WPF/VS-only files). New Roslyn code may also require new editor APIs in src/Morgania.Editor.
• CS0507 or internal-access errors — the IgnoresAccessChecksToGenerator publicizer is involved; the vendored code accesses internals of the public Roslyn packages, so check the publicized assembly list rather than making code changes.
• Runtime load failures / MissingMethodException around remoting — the private DLLs (LanguageServer.Protocol, Remote.Workspaces) were built against specific versions of StreamJsonRpc, MessagePack, Nerdbank.Streams, and Microsoft.VisualStudio.Threading; check the private nuspec's dependencies and bump those pins in Directory.Packages.props to match.
• Restore errors on RestoreHelper — it has its own RestoreSources (dnceng + vssdk + vs-impl + nuget.org) and suppresses NU1603/NU1605; verify the private version string is exact.
• Missing LSP types (Roslyn.Core / Roslyn.Text namespaces, Microsoft.CodeAnalysis.Suggestions, code-cleanup types) — the private packages' lib/<tfm> folder can change between Roslyn versions (5.3.0 shipped lib/net8.0; 5.6.0 ships lib/net10.0). RestoreHelper's GetLibReferences glob then matches nothing and the DLLs silently drop out of the reference list. Check ls ~/.nuget/packages/microsoft.codeanalysis.languageserver.protocol/<ver>/lib/ and align RestoreHelper's TargetFramework/glob with it.

Fix issues in both the Morgania projects and RoslynPad — don't stop at a green build; both apps must run.