Implemented more tests and made use of .git files when adding submodules

There is some more work to do, as renames and updates still have to be
adjusted accordinlgy.

Relates #233

Author: Byron

git/objects/submodule/base.py

@@ -127,6 +127,10 @@ def _get_intermediate_items(self, item):
             return list()
         # END handle intermeditate items
 
+    @classmethod
+    def _need_gitfile_submodules(cls, git):
+        return git.version_info[:3] >= (1, 8, 0)
+
     def __eq__(self, other):
         """Compare with another submodule"""
         # we may only compare by name as this should be the ID they are hashed with
@@ -157,9 +161,7 @@ def _config_parser(cls, repo, parent_commit, read_only):
             access of the config parser"""
         parent_matches_head = repo.head.commit == parent_commit
         if not repo.bare and parent_matches_head:
-            fp_module = cls.k_modules_file
-            fp_module_path = os.path.join(repo.working_tree_dir, fp_module)
-            fp_module = fp_module_path
+            fp_module = os.path.join(repo.working_tree_dir, cls.k_modules_file)
         else:
             try:
                 fp_module = cls._sio_modules(parent_commit)
@@ -198,6 +200,23 @@ def _config_parser_constrained(self, read_only):
         parser.set_submodule(self)
         return SectionConstraint(parser, sm_section(self.name))
 
+    @classmethod
+    def _module_abspath(cls, parent_repo, path, name):
+        if cls._need_gitfile_submodules(parent_repo.git):
+            return os.path.join(parent_repo.git_dir, 'modules', name)
+        else:
+            return os.path.join(parent_repo.working_tree_dir, path)
+        # end
+
+    @classmethod
+    def _write_git_file(cls, working_tree_dir, module_abspath, overwrite_existing=False):
+        """Writes a .git file containing a (preferably) relative path to the actual git module repository.
+        It is an error if the module_abspath cannot be made into a relative path, relative to the working_tree_dir
+        :param working_tree_dir: directory to write the .git file into
+        :param module_abspath: absolute path to the bare repository
+        :param overwrite_existing: if True, we may rewrite existing .git files, otherwise we raise"""
+        raise NotImplementedError
+
     #{ Edit Interface
 
     @classmethod
@@ -298,7 +317,17 @@ def add(cls, repo, name, path, url=None, branch=None, no_checkout=False):
             if not branch_is_default:
                 kwargs['b'] = br.name
             # END setup checkout-branch
-            mrepo = git.Repo.clone_from(url, os.path.join(repo.working_tree_dir, path), **kwargs)
+            module_abspath = cls._module_abspath(repo, path, name)
+            module_checkout_path = module_abspath
+            if cls._need_gitfile_submodules(repo.git):
+                kwargs['separate_git_dir'] = module_abspath
+                module_abspath_dir = os.path.dirname(module_abspath)
+                if not os.path.isdir(module_abspath_dir):
+                    os.makedirs(module_abspath_dir)
+                module_checkout_path = os.path.join(repo.working_tree_dir, path)
+            # end
+
+            mrepo = git.Repo.clone_from(url, module_checkout_path, **kwargs)
         # END verify url
 
         # update configuration and index
@@ -390,7 +419,7 @@ def update(self, recursive=False, init=True, to_latest_revision=False, progress=
             import git
 
             # there is no git-repository yet - but delete empty paths
-            module_path = join_path_native(self.repo.working_tree_dir, self.path)
+            module_path = self._module_abspath(self.repo, self.path, self.name)
             if not dry_run and os.path.isdir(module_path):
                 try:
                     os.rmdir(module_path)

git/test/test_submodule.py

@@ -16,6 +16,7 @@
 from git.objects.submodule.root import RootModule, RootUpdateProgress
 from git.util import to_native_path_linux, join_path_native
 from git.compat import string_types
+from git.repo.fun import find_git_dir
 
 from nose import SkipTest
 
@@ -602,15 +603,56 @@ def test_first_submodule(self, rwrepo):
 
     @with_rw_directory
     def test_add_empty_repo(self, rwdir):
-        parent_dir = os.path.join(rwdir, 'parent')
-        os.mkdir(parent_dir)
         empty_repo_dir = os.path.join(rwdir, 'empty-repo')
 
-        parent = git.Repo.init(parent_dir)
+        parent = git.Repo.init(os.path.join(rwdir, 'parent'))
         git.Repo.init(empty_repo_dir)
 
         for checkout_mode in range(2):
             name = 'empty' + str(checkout_mode)
             self.failUnlessRaises(ValueError, parent.create_submodule, name, name,
                                   url=empty_repo_dir, no_checkout=checkout_mode and True or False)
         # end for each checkout mode
+
+    def _submodule_url(self):
+        return os.path.join(self.rorepo.working_tree_dir, 'git/ext/gitdb/gitdb/ext/smmap')
+
+    @with_rw_directory
+    def test_git_submodules(self, rwdir):
+        parent = git.Repo.init(os.path.join(rwdir, 'parent'))
+        parent.git.submodule('add', self._submodule_url(), 'module')
+        parent.index.commit("added submodule")
+
+        assert len(parent.submodules) == 1
+        sm = parent.submodules[0]
+
+        assert sm.exists() and sm.module_exists()
+
+        # test move and rename
+        # TODO
+
+    @with_rw_directory
+    def test_git_submodule_compatibility(self, rwdir):
+        parent = git.Repo.init(os.path.join(rwdir, 'parent'))
+        empty_file = os.path.join(parent.working_tree_dir, "empty")
+        with open(empty_file, 'wb') as fp:
+            fp.close()
+        parent.index.add([empty_file])
+        parent.index.commit("initial commit - can't yet add submodules to empty parent dir")
+
+        sm_path = 'submodules/intermediate/one'
+        sm = parent.create_submodule('mymodules/myname', sm_path, url=self._submodule_url())
+        parent.index.commit("added submodule")
+
+        # As git is backwards compatible itself, it would still recognize what we do here ... unless we really
+        # muss it up. That's the only reason why the test is still here ... .
+        assert len(parent.git.submodule().splitlines()) == 1
+
+        module_repo_path = os.path.join(sm.module().working_tree_dir, '.git')
+        assert module_repo_path.startswith(os.path.join(parent.working_tree_dir, sm_path))
+        if not sm._need_gitfile_submodules(parent.git):
+            assert os.path.isdir(module_repo_path)
+        else:
+            assert os.path.isfile(module_repo_path)
+            assert find_git_dir(module_repo_path) is not None, "module pointed to by .git file must be valid"
+        # end verify submodule 'style'