SCM: allow multiple DVC repos inside single SCM repo

dvc/command/init.py

@@ -15,7 +15,10 @@ def run(self):
 
         try:
             self.repo = Repo.init(
-                ".", no_scm=self.args.no_scm, force=self.args.force
+                ".",
+                no_scm=self.args.no_scm,
+                force=self.args.force,
+                subdir=self.args.subdir,
             )
             self.config = self.repo.config
         except InitError:
@@ -56,4 +59,13 @@ def add_parser(subparsers, parent_parser):
             "This operation removes local cache."
         ),
     )
+    init_parser.add_argument(
+        "--subdir",
+        action="store_true",
+        default=False,
+        help=(
+            "Necessary for running this command inside a subdirectory of a "
+            "parent SCM repository."
+        ),
+    )
     init_parser.set_defaults(func=CmdInit)

dvc/config.py

@@ -115,6 +115,7 @@ class RelPath(str):
         Optional("interactive", default=False): Bool,
         Optional("analytics", default=True): Bool,
         Optional("hardlink_lock", default=False): Bool,
+        Optional("no_scm", default=False): Bool,
     },
     "cache": {
         "local": str,

dvc/ignore.py

@@ -71,10 +71,25 @@ def __eq__(self, other):
         return self.basenames == other.basenames
 
 
+class DvcIgnoreRepo(DvcIgnore):
+    def __call__(self, root, dirs, files):
+        def is_dvc_repo(directory):
+            from dvc.repo import Repo
+
+            return os.path.isdir(os.path.join(directory, Repo.DVC_DIR))
+
+        dirs = [d for d in dirs if not is_dvc_repo(d)]
+
+        return dirs, files
+
+
 class DvcIgnoreFilter(object):
     def __init__(self, tree):
         self.tree = tree
-        self.ignores = {DvcIgnoreDirs([".git", ".hg", ".dvc"])}
+        self.ignores = {
+            DvcIgnoreDirs([".git", ".hg", ".dvc"]),
+            DvcIgnoreRepo(),
+        }
         for root, dirs, files in self.tree.walk(self.tree.tree_root):
             self._update(root)
             dirs[:], files[:] = self(root, dirs, files)

dvc/repo/__init__.py

@@ -78,7 +78,8 @@ def __init__(self, root_dir=None):
 
         self.config = Config(self.dvc_dir)
 
-        self.scm = SCM(self.root_dir)
+        no_scm = self.config["core"].get("no_scm", False)
+        self.scm = SCM(self.root_dir, no_scm=no_scm)
 
         self.tree = WorkingTree(self.root_dir)
 
@@ -146,10 +147,10 @@ def find_dvc_dir(cls, root=None):
         return os.path.join(root_dir, cls.DVC_DIR)
 
     @staticmethod
-    def init(root_dir=os.curdir, no_scm=False, force=False):
+    def init(root_dir=os.curdir, no_scm=False, force=False, subdir=False):
         from dvc.repo.init import init
 
-        init(root_dir=root_dir, no_scm=no_scm, force=force)
+        init(root_dir=root_dir, no_scm=no_scm, force=force, subdir=subdir)
         return Repo(root_dir)
 
     def unprotect(self, target):

dvc/repo/init.py

@@ -7,8 +7,8 @@
 from dvc.config import Config
 from dvc.exceptions import InitError
 from dvc.repo import Repo
-from dvc.scm import NoSCM
 from dvc.scm import SCM
+from dvc.scm.base import SCMError
 from dvc.utils import boxify
 from dvc.utils import relpath
 from dvc.utils.fs import remove
@@ -44,7 +44,7 @@ def _welcome_message():
     logger.info(msg)
 
 
-def init(root_dir=os.curdir, no_scm=False, force=False):
+def init(root_dir=os.curdir, no_scm=False, force=False, subdir=False):
     """
     Creates an empty repo on the given directory -- basically a
     `.dvc` directory with subdirectories for configuration and cache.
@@ -63,15 +63,23 @@ def init(root_dir=os.curdir, no_scm=False, force=False):
     Raises:
         KeyError: Raises an exception.
     """
+
+    if no_scm and subdir:
+        raise InitError(
+            "Cannot initialize repo with `--no-scm` and `--subdir`"
+        )
+
     root_dir = os.path.realpath(root_dir)
     dvc_dir = os.path.join(root_dir, Repo.DVC_DIR)
-    scm = SCM(root_dir)
-    if isinstance(scm, NoSCM) and not no_scm:
+
+    try:
+        scm = SCM(root_dir, search_parent_directories=subdir, no_scm=no_scm)
+    except SCMError:
         raise InitError(
-            "{repo} is not tracked by any supported scm tool (e.g. git). "
-            "Use `--no-scm` if you don't want to use any scm.".format(
-                repo=root_dir
-            )
+            "{repo} is not tracked by any supported SCM tool (e.g. Git). "
+            "Use `--no-scm` if you don't want to use any SCM or "
+            "`--subdir` if initializing inside a subdirectory of a parent SCM "
+            "repository.".format(repo=root_dir)
         )
 
     if os.path.isdir(dvc_dir):
@@ -87,6 +95,11 @@ def init(root_dir=os.curdir, no_scm=False, force=False):
     os.mkdir(dvc_dir)
 
     config = Config.init(dvc_dir)
+
+    if no_scm:
+        with config.edit() as conf:
+            conf["core"]["no_scm"] = True
+
     proj = Repo(root_dir)
 
     scm.add([config.files["repo"]])

dvc/scm/__init__.py

@@ -10,18 +10,23 @@ class NoSCM(Base):
     pass
 
 
-def SCM(root_dir):  # pylint: disable=invalid-name
+def SCM(
+    root_dir, search_parent_directories=True, no_scm=False
+):  # pylint: disable=invalid-name
     """Returns SCM instance that corresponds to a repo at the specified
     path.
 
     Args:
         root_dir (str): path to a root directory of the repo.
-        repo (dvc.repo.Repo): DVC repo instance that root_dir belongs to.
+        search_parent_directories (bool): whether to look for repo root in
+        parent directories.
+        no_scm (bool): return NoSCM if True.
 
     Returns:
         dvc.scm.base.Base: SCM instance.
     """
-    if Git.is_repo(root_dir) or Git.is_submodule(root_dir):
-        return Git(root_dir)
 
-    return NoSCM(root_dir)
+    if no_scm:
+        return NoSCM(root_dir)
+
+    return Git(root_dir, search_parent_directories=search_parent_directories)

dvc/scm/base.py

@@ -28,7 +28,11 @@ class Base(object):
     """Base class for source control management driver implementations."""
 
     def __init__(self, root_dir=os.curdir):
-        self.root_dir = os.path.realpath(root_dir)
+        self._root_dir = os.path.realpath(root_dir)
+
+    @property
+    def root_dir(self):
+        return self._root_dir
 
     def __repr__(self):
         return "{class_name}: '{directory}'".format(

dvc/scm/git/__init__.py

@@ -22,7 +22,7 @@ class Git(Base):
     GITIGNORE = ".gitignore"
     GIT_DIR = ".git"
 
-    def __init__(self, root_dir=os.curdir):
+    def __init__(self, root_dir=os.curdir, search_parent_directories=True):
         """Git class constructor.
         Requires `Repo` class from `git` module (from gitpython package).
         """
@@ -32,10 +32,12 @@ def __init__(self, root_dir=os.curdir):
         from git.exc import InvalidGitRepositoryError
 
         try:
-            self.repo = git.Repo(self.root_dir)
+            self.repo = git.Repo(
+                root_dir, search_parent_directories=search_parent_directories
+            )
         except InvalidGitRepositoryError:
             msg = "{} is not a git repository"
-            raise SCMError(msg.format(self.root_dir))
+            raise SCMError(msg.format(root_dir))
 
         # NOTE: fixing LD_LIBRARY_PATH for binary built by PyInstaller.
         # http://pyinstaller.readthedocs.io/en/stable/runtime-information.html
@@ -46,6 +48,10 @@ def __init__(self, root_dir=os.curdir):
         self.ignored_paths = []
         self.files_to_track = set()
 
+    @property
+    def root_dir(self):
+        return self.repo.working_tree_dir
+
     @staticmethod
     def clone(url, to_path, rev=None):
         import git
@@ -95,14 +101,6 @@ def is_sha(rev):
 
         return rev and git.Repo.re_hexsha_shortened.search(rev)
 
-    @staticmethod
-    def is_repo(root_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)

tests/dir_helpers.py

@@ -99,7 +99,9 @@ def init(self, *, scm=False, dvc=False):
         if scm:
             _git_init(str_path)
         if dvc:
-            self.dvc = Repo.init(str_path, no_scm=True)
+            self.dvc = Repo.init(
+                str_path, no_scm=not scm and not hasattr(self, "scm")
+            )
         if scm:
             self.scm = self.dvc.scm if hasattr(self, "dvc") else Git(str_path)
         if dvc and hasattr(self, "scm"):

tests/func/test_ignore.py

@@ -4,7 +4,12 @@
 import pytest
 
 from dvc.exceptions import DvcIgnoreInCollectedDirError
-from dvc.ignore import DvcIgnore, DvcIgnoreDirs, DvcIgnorePatterns
+from dvc.ignore import (
+    DvcIgnore,
+    DvcIgnoreDirs,
+    DvcIgnorePatterns,
+    DvcIgnoreRepo,
+)
 from dvc.scm.tree import WorkingTree
 from dvc.utils import relpath
 from dvc.compat import fspath_py35, fspath
@@ -93,10 +98,15 @@ def test_ignore_collecting_dvcignores(tmp_dir, dvc, dname):
     ignore_file = tmp_dir / dname / DvcIgnore.DVCIGNORE_FILE
     ignore_file.write_text("foo")
 
-    assert dvc.tree.dvcignore.ignores == {
-        DvcIgnoreDirs([".git", ".hg", ".dvc"]),
-        DvcIgnorePatterns(fspath(top_ignore_file), WorkingTree(dvc.root_dir)),
-    }
+    assert len(dvc.tree.dvcignore.ignores) == 3
+    assert DvcIgnoreDirs([".git", ".hg", ".dvc"]) in dvc.tree.dvcignore.ignores
+    assert (
+        DvcIgnorePatterns(fspath(top_ignore_file), WorkingTree(dvc.root_dir))
+        in dvc.tree.dvcignore.ignores
+    )
+    assert any(
+        i for i in dvc.tree.dvcignore.ignores if isinstance(i, DvcIgnoreRepo)
+    )
 
 
 def test_ignore_on_branch(tmp_dir, scm, dvc):

tests/func/test_init.py

@@ -1,5 +1,8 @@
+import logging
 import os
 
+from dvc.compat import fspath
+from dvc.config import Config
 from dvc.exceptions import InitError
 from dvc.main import main
 from dvc.repo import Repo as DvcRepo
@@ -49,25 +52,53 @@ def test_cli(self):
         self.assertNotEqual(ret, 0)
 
 
-class TestInitNoSCM(TestDir):
-    def _test_init(self):
-        self.assertTrue(os.path.exists(DvcRepo.DVC_DIR))
-        self.assertTrue(os.path.isdir(DvcRepo.DVC_DIR))
+def test_init_no_scm_api(tmp_dir):
+    repo = DvcRepo.init(no_scm=True)
 
-    def test_api(self):
-        DvcRepo.init(no_scm=True)
+    assert (tmp_dir / DvcRepo.DVC_DIR).is_dir()
+    assert repo.config["core"]["no_scm"]
 
-        self._test_init()
 
-    def test_cli(self):
-        ret = main(["init", "--no-scm"])
-        self.assertEqual(ret, 0)
+def test_init_no_scm_cli(tmp_dir):
+    ret = main(["init", "--no-scm"])
+    assert ret == 0
 
-        self._test_init()
+    dvc_path = tmp_dir / DvcRepo.DVC_DIR
+    assert dvc_path.is_dir()
+    assert Config(fspath(dvc_path))["core"]["no_scm"]
 
 
 def test_init_quiet_should_not_display_welcome_screen(tmp_dir, scm, caplog):
     ret = main(["init", "--quiet"])
 
     assert 0 == ret
     assert "" == caplog.text
+
+
+def test_allow_init_dvc_subdir(tmp_dir, scm, monkeypatch):
+    tmp_dir.gen({"subdir": {}})
+
+    with monkeypatch.context() as m:
+        m.chdir("subdir")
+        assert main(["init", "--subdir"]) == 0
+
+    repo = DvcRepo("subdir")
+    assert repo.root_dir == fspath(tmp_dir / "subdir")
+    assert repo.scm.root_dir == fspath(tmp_dir)
+
+
+def test_subdir_init_no_option(tmp_dir, scm, monkeypatch, caplog):
+    tmp_dir.gen({"subdir": {}})
+
+    caplog.clear()
+    with monkeypatch.context() as m:
+        m.chdir("subdir")
+        with caplog.at_level(logging.ERROR, logger="dvc"):
+            assert main(["init"]) == 1
+
+    assert (
+        "{} is not tracked by any supported SCM tool (e.g. Git). "
+        "Use `--no-scm` if you don't want to use any SCM or "
+        "`--subdir` if initializing inside a subdirectory of a parent SCM "
+        "repository.".format(fspath(tmp_dir / "subdir"))
+    ) in caplog.text