Emit warning for projects detected in multiple drives

[mruxmohan4]

Use absolute instead of relative paths when the folder in a solution file is on a different drive from the root solution path and emit warning, as discussed in #512.

[mruxmohan4]

Output after reproducing the issue locally post-fix:

Build started 11/15/2023 4:11:51 PM.
Generating solution for project "Q:\ProjectB\ProjectB.vcxitems"
Generating solution for project "C:\src\test\slngen-vcxitems\ProjectA\ProjectA.vcxitems"
Loading project references...
Loaded 2 project(s) in 173ms
Generating Visual Studio solution "Q:\ProjectB\Test.sln" ...
Updating existing solution file and reusing Visual Studio cache
SlnGen : warning : Detected folder on a different drive from the root solution path Q:\ProjectB\Test.sln. This folder should not be committed to source control since it does not contain a simple, relative path and is not guaranteed to work across machines.
Launching Visual Studio...

Success

SlnGen : warning : Detected folder on a different drive from the root solution path Q:\ProjectB\Test.sln. This folder should not be committed to source control since it does not contain a simple, relative path and is not guaranteed to work across machines.
    1 Warning(s)
    0 Error(s)

[mruxmohan4]

@jeffkl - Should multiple drives be detected before this section as well (as in, should this solution path, which is written to the stream, use absolute paths)?

[jeffkl]

I don't think detecting multiple drives is the right thing to do. Instead, if the drive that the current project is different from the drive that the solution file is being saved to, we need to use rooted absolute paths for that project's entry. If the project is on the same drive, the path should be relative. If one or more projects are on a different drive, then emit the warning. Does that sound right to you?

[mruxmohan4]

I added a condition to detect whether the current project's drive is different from that of the solution file to ensure absolute paths are used if that differs, but I still needed to include the hasFullPath check since that led to the ArgumentException (the hierarchy includes a topmost-level folder that has "" for its absolute path).

[mruxmohan4]

Latest test output:

Microsoft Visual Studio Solution File, Format Version 12.00
Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "ProjectA", "C:\src\test\slngen-vcxitems\ProjectA\ProjectA.vcxitems", "{369B6908-BF24-4C02-8BB0-4139FD699D1D}"
EndProject
Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "ProjectB", "ProjectB.vcxitems", "{905547D1-E9AF-4D80-8F83-2751E83D4557}"
EndProject
Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "ProjectA", "C:\src\test\slngen-vcxitems\ProjectA", "{18234187-1FD6-4D2F-A26A-F9FC5FD67E9E}"
EndProject
Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "slngen-vcxitems", "C:\src\test\slngen-vcxitems", "{048D148C-0E53-4770-A80E-40E40B181400}"
EndProject
Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "test", "C:\src\test", "{59CC9E02-BE3C-4BCD-96A1-3243B7D7036F}"
EndProject
Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "C:\src", "{D275FB7E-3968-465B-9679-3E738EB5E583}"
EndProject
Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "ProjectB", "..\ProjectB", "{642B108B-866B-4B78-AD36-FAF88B6ECD4E}"
EndProject
Global
	GlobalSection(SolutionConfigurationPlatforms) = preSolution
		Debug|x64 = Debug|x64
		Release|x64 = Release|x64
	EndGlobalSection
	GlobalSection(ProjectConfigurationPlatforms) = postSolution
	EndGlobalSection
	GlobalSection(SolutionProperties) = preSolution
		HideSolutionNode = FALSE
	EndGlobalSection
	GlobalSection(NestedProjects) = preSolution
		{369B6908-BF24-4C02-8BB0-4139FD699D1D} = {18234187-1FD6-4D2F-A26A-F9FC5FD67E9E}
		{18234187-1FD6-4D2F-A26A-F9FC5FD67E9E} = {048D148C-0E53-4770-A80E-40E40B181400}
		{048D148C-0E53-4770-A80E-40E40B181400} = {59CC9E02-BE3C-4BCD-96A1-3243B7D7036F}
		{59CC9E02-BE3C-4BCD-96A1-3243B7D7036F} = {D275FB7E-3968-465B-9679-3E738EB5E583}
		{D275FB7E-3968-465B-9679-3E738EB5E583} = {BBAA5F6C-FCF6-4088-8AB6-C7650C6BE6AB}
		{905547D1-E9AF-4D80-8F83-2751E83D4557} = {642B108B-866B-4B78-AD36-FAF88B6ECD4E}
		{642B108B-866B-4B78-AD36-FAF88B6ECD4E} = {F8F3097E-FE30-46C8-B7CD-C73AEFE68DCE}
	EndGlobalSection
	GlobalSection(ExtensibilityGlobals) = postSolution
		SolutionGuid = {D0FD770F-48DF-419B-9E83-07C49EEFFD41}
	EndGlobalSection
	GlobalSection(SharedMSBuildProjectFiles) = preSolution
	EndGlobalSection
EndGlobal

[jeffkl]

Thanks!