Show a more meaningful message when a project uses build conditions

Author: SteveDesmond-ca

src/LibYear.Core/FileTypes/XmlProjectFile.cs

@@ -31,6 +31,9 @@ protected XmlProjectFile(string filename, string contents, string elementName, s
 		_xmlContents = XDocument.Parse(contents);
 		_whitespace = DetermineWhitespace(contents);
 
+		if (_xmlContents.Root is not null && _xmlContents.Root.DescendantsAndSelf().Any(e => e.Attribute("Condition") is not null))
+			throw new ArgumentException("Project files with conditions are not supported");
+
 		Packages = _xmlContents.Descendants(elementName)
 			.ToDictionary(
 				d => packageAttributeNames.Select(p => d.Attribute(p)?.Value ?? d.Element(p)?.Value).FirstOrDefault(v => v != null)!,

test/LibYear.Core.Tests/FileTypes/CsProjFileTests.cs

@@ -118,7 +118,7 @@ public async Task InvalidVersionShowsExceptionDetails()
 		{
 			//act
 			_ = new CsProjFile(filename, newContents);
-			Assert.False(true);
+			Assert.Fail();
 		}
 		catch (Exception e)
 		{
@@ -142,4 +142,24 @@ public async Task VersionRangeGetsSkipped()
 		//assert
 		Assert.Null(file.Packages["test8"]);
 	}
+
+	[Fact]
+	public async Task ProjectBuildConditionsThrowException()
+	{
+		//arrange
+		var filename = Path.Combine("FileTypes", "project.csproj");
+		var contents = @"<Project Sdk=""Microsoft.NET.Sdk""><ItemGroup Condition=""'$(TargetFramework)' == 'net8.0'""></ItemGroup></Project>";
+
+		try
+		{
+			//act
+			_ = new CsProjFile(filename, contents);
+			Assert.Fail();
+		}
+		catch (Exception e)
+		{
+			//assert
+			Assert.Contains("not supported", e.Message);
+		}
+	}
 }