Add check that env_root dir exists

lib/spack/spack/environment/environment.py

@@ -248,6 +248,12 @@ def read(name):
 
 def create(name, init_file=None, with_view=None, keep_relative=False):
     """Create a named environment in Spack."""
+    if not os.path.isdir(env_root_path()):
+        # double check that the root path exists before we check the full environment name
+        raise SpackEnvironmentError(
+            "The environments_root '{er}' does not exist.  Please create the directory or provide "
+            "a valid path in the config.yaml".format(er=env_root_path())
+        )
     validate_env_name(name)
     if exists(name):
         raise SpackEnvironmentError("'%s': environment already exists" % name)

lib/spack/spack/test/config.py

@@ -1441,12 +1441,25 @@ def test_environment_created_in_users_location(mutable_config, tmpdir):
     """Test that an environment is created in a location based on the config"""
     spack.config.set("config:environments_root", str(tmpdir.join("envs")))
     env_dir = spack.config.get("config:environments_root")
+
     assert tmpdir.strpath in env_dir
     assert not os.path.isdir(env_dir)
+
     os.makedirs(env_dir)
     env("create", "test")
     out = env("list")
-    assert "test" in out
 
+    assert "test" in out
     assert env_dir in ev.root("test")
     assert os.path.isdir(os.path.join(env_dir, "test"))
+
+
+def test_environment_errors_if_root_missing(mutable_config, tmpdir):
+    spack.config.set("config:environments_root", str(tmpdir.join("envs")))
+    env_dir = spack.config.get("config:environments_root")
+
+    assert tmpdir.strpath in env_dir
+    assert not os.path.isdir(env_dir)
+
+    with pytest.raises(ev.SpackEnvironmentError, match=env_dir):
+        env("create", "test")