CI - C# quickstart test properly uses nuget (#3466)

# Description of Changes

The quickstart smoketest was not correctly fudging our NuGet
dependencies to use the local versions of the packages, so it was
pulling them from NuGet. This ended up causing issues when we tried to
modify local packages and then use them in a way that affected the
quickstart (e.g.
#3386).

We had a few issues: we weren't ensuring that the local packages were
built, we weren't using the right directory for those packages, and we
weren't adding a "package source mapping" that forced those packages to
be used from the local directory.

# API and ABI breaking changes

None. CI-only.

# Expected complexity level and risk

2

# Testing

- [x] CI passes when
#3386 is merged
together with this PR (it wasn't before).

---------

Co-authored-by: Zeke Foppa <bfops@users.noreply.github.com>

Author: bfops

.github/workflows/ci.yml

@@ -67,8 +67,8 @@ jobs:
       - uses: actions/setup-python@v5
         with: { python-version: '3.12' }
         if: runner.os == 'Windows'
-      - name: Install psycopg2
-        run: python -m pip install psycopg2-binary
+      - name: Install python deps
+        run: python -m pip install psycopg2-binary xmltodict
       - name: Run smoketests
         # Note: clear_database and replication only work in private
         run: python -m smoketests ${{ matrix.smoketest_args }} -x clear_database replication

smoketests/tests/quickstart.py

@@ -3,6 +3,7 @@
 import shutil
 from pathlib import Path
 import tempfile
+import xmltodict
 
 import smoketests
 from .. import Smoketest, STDB_DIR, run_cmd, TEMPLATE_CARGO_TOML
@@ -43,17 +44,57 @@ def _parse_quickstart(doc_path: Path, language: str) -> str:
     # So we could have a different db for each language
     return "\n".join(blocks).replace("quickstart-chat", f"quickstart-chat-{language}") + end
 
-
-def _dotnet_add_package(project_path: Path, package_name: str, source_path: Path):
-    """Add a local NuGet package to a .NET project"""
-    sources = run_cmd("dotnet", "nuget", "list", "source", cwd=project_path, capture_stderr=True)
-    # Is the source already added?
-    if package_name in sources:
-        run_cmd("dotnet", "nuget", "remove", "source", package_name, cwd=project_path, capture_stderr=True)
-    run_cmd("dotnet", "nuget", "add", "source", source_path, "--name", package_name, cwd=project_path,
-            capture_stderr=True)
-    run_cmd("dotnet", "add", "package", package_name, cwd=project_path, capture_stderr=True)
-
+def load_nuget_config(p: Path):
+    if p.exists():
+        with p.open("rb") as f:
+            return xmltodict.parse(f.read(), force_list=["add", "packageSource", "package"])
+    return {}
+
+def save_nuget_config(p: Path, doc: dict):
+    # Write back (pretty, UTF-8, no BOM)
+    xml = xmltodict.unparse(doc, pretty=True)
+    p.write_text(xml, encoding="utf-8")
+
+def add_source(doc: dict, *, key: str, path: str) -> None:
+    cfg = doc.setdefault("configuration", {})
+    sources = cfg.setdefault("packageSources", {})
+    source_entries = sources.setdefault("add", [])
+    source = {"@key": key, "@value": path}
+    source_entries.append(source)
+
+def add_mapping(doc: dict, *, key: str, pattern: str) -> None:
+    cfg = doc.setdefault("configuration", {})
+
+    psm = cfg.setdefault("packageSourceMapping", {})
+    mapping_sources = psm.setdefault("packageSource", [])
+
+    # Find or create the target <packageSource key="...">
+    target = next((s for s in mapping_sources if s.get("@key") == key), None)
+    if target is None:
+        target = {"@key": key, "package": []}
+        mapping_sources.append(target)
+
+    pkgs = target.setdefault("package", [])
+
+    existing = {pkg.get("@pattern") for pkg in pkgs if "@pattern" in pkg}
+    if pattern not in existing:
+        pkgs.append({"@pattern": pattern})
+
+def override_nuget_package(*, project_dir: Path, package: str, source_dir: Path, build_subdir: str):
+    """Override nuget config to use a local NuGet package on a .NET project"""
+    # Make sure the local package is built
+    run_cmd("dotnet", "pack", cwd=source_dir)
+
+    p = Path(project_dir) / "nuget.config"
+    doc = load_nuget_config(p)
+    add_source(doc, key=package, path=source_dir/build_subdir)
+    add_mapping(doc, key=package, pattern=package)
+    # Fallback for other packages
+    add_mapping(doc, key="nuget.org", pattern="*")
+    save_nuget_config(p, doc)
+
+    # Clear any caches for nuget packages
+    run_cmd("dotnet", "nuget", "locals", "--clear", "all", capture_stderr=True)
 
 class BaseQuickstart(Smoketest):
     AUTOPUBLISH = False
@@ -246,11 +287,27 @@ def project_init(self, path: Path):
         run_cmd("dotnet", "new", "console", "--name", "QuickstartChatClient", "--output", path, capture_stderr=True)
 
     def sdk_setup(self, path: Path):
-        _dotnet_add_package(path, "SpacetimeDB.ClientSDK", (STDB_DIR / "sdks/csharp").absolute())
+        override_nuget_package(
+            project_dir=STDB_DIR/"sdks/csharp",
+            package="SpacetimeDB.BSATN.Runtime",
+            source_dir=(STDB_DIR / "crates/bindings-csharp/BSATN.Runtime").absolute(),
+            build_subdir="bin/Release"
+        )
+        override_nuget_package(
+            project_dir=path,
+            package="SpacetimeDB.ClientSDK",
+            source_dir=(STDB_DIR / "sdks/csharp").absolute(),
+            build_subdir="bin~/Release"
+        )
+        run_cmd("dotnet", "add", "package", "SpacetimeDB.ClientSDK", cwd=path, capture_stderr=True)
 
     def server_postprocess(self, server_path: Path):
-        _dotnet_add_package(server_path, "SpacetimeDB.Runtime",
-                            (STDB_DIR / "crates/bindings-csharp/Runtime").absolute())
+        override_nuget_package(
+            project_dir=server_path,
+            package="SpacetimeDB.Runtime",
+            source_dir=(STDB_DIR / "crates/bindings-csharp/Runtime").absolute(),
+            build_subdir="bin/Release"
+        )
 
     def test_quickstart(self):
         """Run the C# quickstart guides for server and client."""