Expand relative volume paths for compose on current cwd

plugins/providers/docker/driver/compose.rb

@@ -94,16 +94,16 @@ module VagrantPlugins
           ports   = Array(params[:ports])
           volumes = Array(params[:volumes]).map do |v|
             v = v.to_s
+            host, guest = v.split(":", 2)
             if v.include?(":") && (Vagrant::Util::Platform.windows? || Vagrant::Util::Platform.wsl?)
-              host, guest = v.split(":", 2)
               host = Vagrant::Util::Platform.windows_path(host)
               # NOTE: Docker does not support UNC style paths (which also
               # means that there's no long path support). Hopefully this
               # will be fixed someday and the gsub below can be removed.
               host.gsub!(/^[^A-Za-z]+/, "")
-              v = [host, guest].join(":")
             end
-            v
+            host = @machine.env.cwd.join(host).to_s
+            "#{host}:#{guest}"
           end
           cmd     = Array(params.fetch(:cmd))
           env     = Hash[*params.fetch(:env).flatten.map(&:to_s)]

test/unit/plugins/providers/docker/driver_compose_test.rb

@@ -41,6 +41,7 @@ describe VagrantPlugins::DockerProvider::Driver::Compose do
     allow(Vagrant::Util::Which).to receive(:which).and_return("/dev/null/docker-compose")
     allow(env).to receive(:lock).and_yield
     allow(Pathname).to receive(:new).with(local_data_path).and_return(local_data_path)
+    allow(Pathname).to receive(:new).with('/host/path').and_call_original
     allow(local_data_path).to receive(:join).and_return(data_directory)
     allow(data_directory).to receive(:mkpath)
     allow(FileUtils).to receive(:mv)
@@ -93,6 +94,18 @@ describe VagrantPlugins::DockerProvider::Driver::Compose do
       end
     end
 
+    context 'with relative path in share folders' do
+      before do
+        params[:volumes] = './path:guest/path'
+        allow(Pathname).to receive(:new).with('./path').and_call_original
+        allow(Pathname).to receive(:new).with('/compose/cwd/path').and_call_original
+      end
+
+      it 'should expand the relative host directory' do
+        expect(docker_yml).to receive(:write).with(%r{/compose/cwd/path})
+      end
+    end
+
     it 'links containers' do
       params[:links].each do |link|
         expect(docker_yml).to receive(:write).with(/#{link}/)