From bbd5096de7ae486683e18a2645cc8cb255b80663 Mon Sep 17 00:00:00 2001
From: Jeep Kiddee <nutthawut.ki@gmail.com>
Date: Fri, 21 Sep 2018 01:41:00 +0700
Subject: [PATCH] scm: support git submodule

Fixes #1093
---
 dvc/scm.py         | 17 ++++++++++++++---
 tests/basic_env.py |  9 +++++++++
 tests/test_scm.py  | 16 +++++++++++++++-
 3 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/dvc/scm.py b/dvc/scm.py
index cb7bf107b..63333c716 100644
--- a/dvc/scm.py
+++ b/dvc/scm.py
@@ -22,6 +22,10 @@ class Base(object):
     def is_repo(root_dir):
         return True
 
+    @staticmethod
+    def is_submodule(root_dir):
+        return True
+
     def ignore(self, path):
         pass
 
@@ -98,8 +102,15 @@ class Git(Base):
 
     @staticmethod
     def is_repo(root_dir):
-        git_dir = os.path.join(root_dir, Git.GIT_DIR)
-        return os.path.isdir(git_dir)
+        return os.path.isdir(Git._get_git_dir(root_dir))
+
+    @staticmethod
+    def is_submodule(root_dir):
+        return os.path.isfile(Git._get_git_dir(root_dir))
+
+    @staticmethod
+    def _get_git_dir(root_dir):
+        return os.path.join(root_dir, Git.GIT_DIR)
 
     @property
     def dir(self):
@@ -211,7 +222,7 @@ class Git(Base):
 
 
 def SCM(root_dir, no_scm=False, project=None):
-    if Git.is_repo(root_dir):
+    if Git.is_repo(root_dir) or Git.is_submodule(root_dir):
         return Git(root_dir, project=project)
 
     return Base(root_dir, project=project)
diff --git a/tests/basic_env.py b/tests/basic_env.py
index 2445f5afd..8c865a25d 100644
--- a/tests/basic_env.py
+++ b/tests/basic_env.py
@@ -61,6 +61,15 @@ class TestGit(TestDir):
         self.git.index.commit('add code')
 
 
+class TestGitSubmodule(TestGit):
+    def setUp(self):
+        super(TestGitSubmodule, self).setUp()
+        subrepo = Repo.init()
+        subrepo_path = 'subrepo'
+        self.git.create_submodule(subrepo_path, subrepo_path, subrepo.git_dir)
+        self._pushd(subrepo_path)
+
+
 class TestDvc(TestGit):
     def setUp(self):
         super(TestDvc, self).setUp()
diff --git a/tests/test_scm.py b/tests/test_scm.py
index 9f7a4b51c..2e134c24c 100644
--- a/tests/test_scm.py
+++ b/tests/test_scm.py
@@ -4,7 +4,7 @@ from git import Repo
 
 from dvc.scm import SCM, Base, Git
 
-from tests.basic_env import TestDir, TestGit
+from tests.basic_env import TestDir, TestGit, TestGitSubmodule
 
 
 class TestSCM(TestDir):
@@ -27,6 +27,20 @@ class TestSCMGit(TestGit):
         self.assertTrue('foo' in self.git.git.ls_files())
 
 
+class TestSCMGitSubmodule(TestGitSubmodule):
+    def test_git_submodule(self):
+        self.assertIsInstance(SCM(os.curdir), Git)
+
+    def test_is_submodule(self):
+        self.assertTrue(Git.is_submodule(os.curdir))
+
+    def test_commit_in_submodule(self):
+        G = Git(self._root_dir)
+        G.add(['foo'])
+        G.commit('add')
+        self.assertTrue('foo' in self.git.git.ls_files())
+
+
 class TestIgnore(TestGit):
     def _count_gitignore(self):
         with open(Git.GITIGNORE, 'r') as fd: