Relative git submodules are not indexed

[NN---]

Given git submodule with relative path:

.gitmodules

[submodule "a"]
   path = a
   url = ../a

SourceLink produces a warning and doesn't index files.

It doesn't produce a warning when a full URL is specified.

[submodule "a"]
   path = a
   url = htttp://github.com/company/a

[tmat]

What warning is reported?

This scenario is covered by test GetSourceRoots_RelativeSubmodulePaths.

[NN---]

packages\Microsoft.Build.Tasks.Git.1.0.0\build\Microsoft.Build.Tasks.Git.targets(24,5): warning : Repository 'c:\project\a.git' has no 
remote.
[c:\project\x\x.vcxproj]

packages\Microsoft.Build.Tasks.Git.1.0.0\build\Microsoft.Build.Tasks.Git.targets(24,5): warning : Repository 'c:\project\b' has no remote.
[c:\project\x\x.vcxproj]

[tmat]

Can you share the structure of all the repositories involved? That is the content of their .git directories (just the files directly in those directories), the .gitmodules file and their locations on disk?
Alternatively, steps to reproduce.

[NN---]

Check this repository: https://github.com/NN---/sourcelinkmain

git clone https://github.com/NN---/sourcelinkmain sourcelinkmain
cd sourcelinkmain
git submodule update
nuget restore sourcelinkmain.sln
devenv sourcelinkmain.sln /build

1>C:\sourcelinkmain\packages\Microsoft.Build.Tasks.Git.1.0.0\build\Microsoft.Build.Tasks.Git.targets(24,5): warning : Repository 'C:\Projects\tests\sourcelinka.git' has no remote.
1>C:\sourcelinkmain\packages\Microsoft.Build.Tasks.Git.1.0.0\build\Microsoft.Build.Tasks.Git.targets(24,5): warning : Repository 'C:\Projects\tests\sourcelinkb' has no remote.

[Zastai]

I have the same issue.

Given

• a project (Foo) cloned in E:\Sources\Foo
• a submodule (Bar) in a subdirectory "xyzzy" (so X:\Sources\Foo\xyzzy)
• .git/config containing

  [core]
  repositoryformatversion = 0
  filemode = false
  bare = false
  logallrefupdates = true
  symlinks = false
  ignorecase = true
  [remote "origin"]
  url = https://github.com/User/Foo.git
  fetch = +refs/heads/*:refs/remotes/origin/*
  [branch "master"]
  remote = origin
  merge = refs/heads/master
  [submodule "xyzzy"]
  url = https://github.com/User/Bar.git
  active = true
  

• .git/HEAD containing ref: refs/heads/master
• .git/refs/heads/master containing 3c7de8936de5825fe868591907962c6b59a9a429
• xyzzy/.git containing gitdir: ../.git/modules/xyzzy
• .git/modules/xyzzy/config containing

  [core]
  repositoryformatversion = 0
  filemode = false
  bare = false
  logallrefupdates = true
  symlinks = false
  ignorecase = true
  worktree = ../../../xyzzy
  [remote "origin"]
  url = https://github.com/User/Bar.git
  fetch = +refs/heads/*:refs/remotes/origin/*
  [branch "master"]
  remote = origin
  merge = refs/heads/master
  

• .git/modules/xyzzy/HEAD containing ref: refs/heads/master
• .git/modules/xyzzy/refs/heads/master containing 03fa592c00fc729c86d7ecb046e25d0895523771

I get multiple cases of

...\microsoft.build.tasks.git\1.0.0\build\Microsoft.Build.Tasks.Git.targets(24,5): warning : Repository 'E:\Sources\Bar.git' has no remote.

Using MSBuild binlog, the first reference to this nonexistent path (E:\Sources\Bar.git) I see is:

Microsoft.Build.Tasks.Git.LocateRepository
    Assembly = ...\microsoft.build.tasks.git\1.0.0\build\..\tools\netcoreapp2.0\Microsoft.Build.Tasks.Git.dll
    Parameters
        Path = E:\Sources\Foo\src
    Warnings
        ...\microsoft.build.tasks.git\1.0.0\build\Microsoft.Build.Tasks.Git.targets(24,5): Repository 'E:\Sources\Bar.git' has no remote. [E:\Sources\Foo\src\Foo.csproj]
    OutputProperties
        _GitRepositoryId = E:\Sources\Foo\.git
        ScmRepositoryUrl = https://github.com/User/Foo.git
        SourceRevisionId = 3c7de8936de5825fe868591907962c6b59a9a429
    OutputItems
        SourceRoot
            E:\Sources\Foo\
                RevisionId = 3c7de8936de5825fe868591907962c6b59a9a429
                ScmRepositoryUrl = https://github.com/User/Foo.git
                SourceControl = git
            E:\Sources\Foo\xyzzy\
                ContainingRoot = E:\Sources\Foo\
                NestedRoot = xyzzy/
                RevisionId = 03fa592c00fc729c86d7ecb046e25d0895523771
                ScmRepositoryUrl = file:///E:/Sources/Bar.git
                SourceControl = git

So this task seems to have no problem finding the source roots and the commit hashes, but computing the RepositoryUrl for submodules goes wrong.

(At first glance, it seems to be correctly appending Bar.git, just to the wrong path (the parent of the local source dir instead of the parent of the repository url.)

[Zastai]

Relevant file I omitted: .gitmodules:

[submodule "build"]
	path = build
	url = ../Bar.git
	branch = master

[Zastai]

Looks like GitRepository gets and reports ../Bar.git as url.
So either that's wrong and should already be resolved, or GitOperations is doing the wrong thing when it is making it absolute.

Note: in my tree at least, .git/modules/xyzzy/config contains a remote name for the branch listed in .gitmodules, and that remote has a full URL, so I am not sure why the code does not follow that path (which would be close to how the main dir is handled anyway).