[Bug]: Check for determining "project file" does not correctly work for solution filter files

[stefan-schweiger]

Issue Description

When running dotnet build in a folder which only contains a .slnf the commands won't work because no valid "project file" can be determined, but if you run dotnet build MyFilter.slnf the commands correctly work.

Steps to Reproduce

Create a solution with the following structure and run dotnet build in the folder ServiceA

/
├─ ServiceA/
│  ├─ ServiceA.QueryHandling/
│  │  ├─ ServiceA.QueryHandling.csproj
│  ├─ ServiceA.slnf
├─ MySolution.sln

Expected Behavior

The build should correctly pick up the solution filter file and work like it would in the / and ServiceA.QueryHandling folders.

Actual Behavior

If you run it in the ServiceA folder you get this error:
MSB1003: Specify a project or solution file. The current working directory does not contain a project or solution file.

Analysis

I think the problem is on line 3422 here that it only looks for *.sln files and therefore never picks up *.slnf files, so it should probably be changed to *.sln* to actually correctly pick up the solution filter files.

msbuild/src/MSBuild/XMake.cs

Lines 3422 to 3497 in 5d663a0

	string[] potentialSolutionFiles = getFiles(projectDirectory ?? ".", "*.sln");
	List<string> actualSolutionFiles = new List<string>();
	List<string> solutionFilterFiles = new List<string>();
	if (potentialSolutionFiles != null)
	{
	foreach (string s in potentialSolutionFiles)
	{
	if (!extensionsToIgnore.Contains(Path.GetExtension(s)))
	{
	if (FileUtilities.IsSolutionFilterFilename(s))
	{
	solutionFilterFiles.Add(s);
	}
	else if (FileUtilities.IsSolutionFilename(s))
	{
	actualSolutionFiles.Add(s);
	}
	}
	}
	}
	// If there is exactly 1 project file and exactly 1 solution file
	if (actualProjectFiles.Count == 1 && actualSolutionFiles.Count == 1)
	{
	// Grab the name of both project and solution without extensions
	string solutionName = Path.GetFileNameWithoutExtension(actualSolutionFiles[0]);
	string projectName = Path.GetFileNameWithoutExtension(actualProjectFiles[0]);
	// Compare the names and error if they are not identical
	InitializationException.VerifyThrow(string.Equals(solutionName, projectName, StringComparison.OrdinalIgnoreCase), projectDirectory == null ? "AmbiguousProjectError" : "AmbiguousProjectDirectoryError", null, projectDirectory);
	projectFile = actualSolutionFiles[0];
	}
	// If there is more than one solution file in the current directory we have no idea which one to use
	else if (actualSolutionFiles.Count > 1)
	{
	InitializationException.VerifyThrow(false, projectDirectory == null ? "AmbiguousProjectError" : "AmbiguousProjectDirectoryError", null, projectDirectory, false);
	}
	// If there is more than one project file in the current directory we may be able to figure it out
	else if (actualProjectFiles.Count > 1)
	{
	// We have more than one project, it is ambiguous at the moment
	bool isAmbiguousProject = true;
	// If there are exactly two projects and one of them is a .proj use that one and ignore the other
	if (actualProjectFiles.Count == 2)
	{
	string firstPotentialProjectExtension = Path.GetExtension(actualProjectFiles[0]);
	string secondPotentialProjectExtension = Path.GetExtension(actualProjectFiles[1]);
	// If the two projects have the same extension we can't decide which one to pick
	if (!string.Equals(firstPotentialProjectExtension, secondPotentialProjectExtension, StringComparison.OrdinalIgnoreCase))
	{
	// Check to see if the first project is the proj, if it is use it
	if (string.Equals(firstPotentialProjectExtension, ".proj", StringComparison.OrdinalIgnoreCase))
	{
	projectFile = actualProjectFiles[0];
	// We have made a decision
	isAmbiguousProject = false;
	}
	// If the first project is not the proj check to see if the second one is the proj, if so use it
	else if (string.Equals(secondPotentialProjectExtension, ".proj", StringComparison.OrdinalIgnoreCase))
	{
	projectFile = actualProjectFiles[1];
	// We have made a decision
	isAmbiguousProject = false;
	}
	}
	}
	InitializationException.VerifyThrow(!isAmbiguousProject, projectDirectory == null ? "AmbiguousProjectError" : "AmbiguousProjectDirectoryError", null, projectDirectory);
	}
	// if there are no project, solution filter, or solution files in the directory, we can't build
	else if (actualProjectFiles.Count == 0 &&
	actualSolutionFiles.Count == 0 &&
	solutionFilterFiles.Count == 0)
	{
	InitializationException.Throw("MissingProjectError", null, null, false);
	}

Versions & Configurations

MSBuild version 17.8.3+195e7f5a3 for .NET
17.8.3.51904%

dotnet 8.0.100

macOS 14.2.1 (23C71)

[stefan-schweiger]

Also I think the "mock" code here

msbuild/src/MSBuild.UnitTests/XMake_Tests.cs

Lines 1931 to 1953 in 5d663a0

	internal string[] GetFiles(string path, string searchPattern)
	{
	List<string> fileNamesToReturn = new List<string>();
	foreach (string file in _directoryFileNameList)
	{
	if (string.Equals(searchPattern, "*.sln", StringComparison.OrdinalIgnoreCase))
	{
	if (FileUtilities.IsSolutionFilename(file))
	{
	fileNamesToReturn.Add(file);
	}
	}
	else if (string.Equals(searchPattern, "*.*proj", StringComparison.OrdinalIgnoreCase))
	{
	if (Path.GetExtension(file).Contains("proj"))
	{
	fileNamesToReturn.Add(file);
	}
	}
	}
	return fileNamesToReturn.ToArray();
	}
	}

for this test does not correctly work

msbuild/src/MSBuild.UnitTests/XMake_Tests.cs

Lines 1614 to 1625 in 5d663a0

	[Theory]
	[InlineData(new[] { "my.proj", "my.sln", "my.slnf" }, "my.sln")]
	[InlineData(new[] { "abc.proj", "bcd.csproj", "slnf.slnf", "other.slnf" }, "abc.proj")]
	[InlineData(new[] { "abc.sln", "slnf.slnf", "abc.slnf" }, "abc.sln")]
	[InlineData(new[] { "abc.csproj", "abc.slnf", "not.slnf" }, "abc.csproj")]
	[InlineData(new[] { "abc.slnf" }, "abc.slnf")]
	public void TestDefaultBuildWithSolutionFilter(string[] projects, string answer)
	{
	string[] extensionsToIgnore = Array.Empty<string>();
	IgnoreProjectExtensionsHelper projectHelper = new IgnoreProjectExtensionsHelper(projects);
	MSBuildApp.ProcessProjectSwitch(Array.Empty<string>(), extensionsToIgnore, projectHelper.GetFiles).ShouldBe(answer, StringCompareShould.IgnoreCase);
	}

[AR-May]

Team triage: @stefan-schweiger your analysis looks good, if you are interested, please send a PR fixing that.

[jrdodds]

This bug has been fixed by Feature Request #10266 and PR #10794. The PR implemented the changes identified by @stefan-schweiger. I confirmed by testing and reviewing the code.

I believe this issue can be closed.

[rainersigwald]

Thanks @jrdodds!