exclude '.tox', '.nox' from being copied during 'pip install .'

news/6770.bugfix

@@ -0,0 +1 @@
+Skip copying .tox and .nox directories to temporary build directories

src/pip/_internal/download.py

@@ -934,12 +934,23 @@ def unpack_file_url(
     of the link file inside download_dir.
     """
     link_path = url_to_path(link.url_without_fragment)
-
     # If it's a url to a local directory
     if is_dir_url(link):
+
+        def ignore(d, names):
+            # Pulling in those directories can potentially
+            # be very slow.
+            # see discussion at:
+            #   https://github.com/pypa/pip/pull/6770
+            return ['.tox', '.nox'] if d == link_path else []
+
         if os.path.isdir(location):
             rmtree(location)
-        shutil.copytree(link_path, location, symlinks=True)
+        shutil.copytree(link_path,
+                        location,
+                        symlinks=True,
+                        ignore=ignore)
+
         if download_dir:
             logger.info('Link is a directory, ignoring download_dir')
         return

tests/unit/test_download.py

@@ -18,7 +18,7 @@
 from pip._internal.exceptions import HashMismatch
 from pip._internal.models.link import Link
 from pip._internal.utils.hashes import Hashes
-from pip._internal.utils.misc import path_to_url
+from pip._internal.utils.misc import ensure_dir, path_to_url
 from tests.lib import create_file
 
 
@@ -413,6 +413,50 @@ def test_unpack_file_url_thats_a_dir(self, tmpdir, data):
         assert os.path.isdir(os.path.join(self.build_dir, 'fspkg'))
 
 
+@pytest.mark.parametrize('exclude_dir', [
+    '.nox',
+    '.tox'
+])
+def test_unpack_file_url_with_excluded_dirs(exclude_dir):
+
+    def touch(path):
+        with open(path, 'a'):
+            os.utime(path, None)
+
+    src_dir = mkdtemp()
+    src_included_file = os.path.join(src_dir, 'file.txt')
+    src_excluded_dir = os.path.join(src_dir, exclude_dir)
+    src_excluded_file = os.path.join(src_dir, exclude_dir, 'file.txt')
+    src_included_dir = os.path.join(src_dir, 'subdir', exclude_dir)
+
+    # set up source directory
+    ensure_dir(src_excluded_dir)
+    ensure_dir(src_included_dir)
+    touch(src_included_file)
+    touch(src_excluded_file)
+
+    dst_dir = mkdtemp()
+    dst_included_file = os.path.join(dst_dir, 'file.txt')
+    dst_excluded_dir = os.path.join(dst_dir, exclude_dir)
+    dst_excluded_file = os.path.join(dst_dir, exclude_dir, 'file.txt')
+    dst_included_dir = os.path.join(dst_dir, 'subdir', exclude_dir)
+
+    try:
+        src_link = Link(path_to_url(src_dir))
+        unpack_file_url(
+            src_link,
+            dst_dir,
+            download_dir=None
+        )
+        assert not os.path.isdir(dst_excluded_dir)
+        assert not os.path.isfile(dst_excluded_file)
+        assert os.path.isfile(dst_included_file)
+        assert os.path.isdir(dst_included_dir)
+    finally:
+        rmtree(src_dir)
+        rmtree(dst_dir)
+
+
 class TestSafeFileCache:
     """
     The no_perms test are useless on Windows since SafeFileCache uses