Normalize git commondir path.

[AustinWise]

The constructor for GitRepositoryLocation asserts that this path is
normalized. On my machine, a git worktree created by Git 2.22.0 does not
result in path that satisfies this assert.

Fixes #473

[AustinWise]

Specifically, the commondir file contains ../... In my limited testing this only effects debug builds. Release builds without Debug.Assert seem happy with the relative path.

[tmat]

Typo in comment. I don't think the comment is needed since it's obvious what GetFullPath does. Also, you can simplify by calling Path.GetFullPath() directly on the previous line Path.GetFullPath(Path.Combine(...))

[tmat]

@AustinWise Thanks for the PR. We are definitely missing GetFullPath call. Would you mind adding a test to GitRepositoryTests, similar to

sourcelink/src/Microsoft.Build.Tasks.Git.UnitTests/GitRepositoryTests.cs

Lines 13 to 37 in b4f237e

	public void TryFindRepository_Worktree()
	{
	using var temp = new TempRoot();
	var mainWorkingDir = temp.CreateDirectory();
	var mainWorkingSubDir = mainWorkingDir.CreateDirectory("A");
	var mainGitDir = mainWorkingDir.CreateDirectory(".git");
	mainGitDir.CreateFile("HEAD");
	var worktreeGitDir = temp.CreateDirectory();
	var worktreeGitSubDir = worktreeGitDir.CreateDirectory("B");
	var worktreeDir = temp.CreateDirectory();
	var worktreeSubDir = worktreeDir.CreateDirectory("C");
	var worktreeGitFile = worktreeDir.CreateFile(".git").WriteAllText("gitdir: " + worktreeGitDir + " \r\n\t\v");
	worktreeGitDir.CreateFile("HEAD");
	worktreeGitDir.CreateFile("commondir").WriteAllText(mainGitDir.Path + " \r\n\t\v");
	worktreeGitDir.CreateFile("gitdir").WriteAllText(worktreeGitFile.Path + " \r\n\t\v");
	// start under main repository directory:
	Assert.True(GitRepository.TryFindRepository(mainWorkingSubDir.Path, out var location));
	Assert.Equal(mainGitDir.Path, location.GitDirectory);
	Assert.Equal(mainGitDir.Path, location.CommonDirectory);
	Assert.Equal(mainWorkingDir.Path, location.WorkingDirectory);

?

[AustinWise]

Ok, I will update with a test and a fix for the typo.

[AustinWise]

@tmat I added tests and fixed the comment. I was not sure if you want me to replace the existing test or add a new one, so for now I added a new one. The existing test creates a git layout that does not match the repository specification nor the layout git worktree currently creates. So perhaps the old test should be replaced with the new test?

[tmat]

Thanks!