Update Roslyn

Updating the Roslyn version

Two things must stay in sync, both pointing at the same Roslyn commit:

1. RoslynVersion in Directory.Packages.props — the public Microsoft.CodeAnalysis.* packages from nuget.org.
2. The vendor/roslyn submodule — EditorFeatures plus selected LanguageServer/Remote sources are recompiled 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 Roslyn commit

The public package's nuspec <description> ends with the matching Roslyn commit. Get that SHA:

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

Step 3 — Update the roslyn submodule

Check out the 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.
• Missing LSP/remote types — check the explicit LanguageServer and Workspaces/Remote source includes in Morgania.CodeAnalysis.EditorFeatures.csproj, the linked decompiler files in RoslynPad.csproj, and MorganiaMefHostServices. Upstream may move or split these files during an upgrade.

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