Ignore environment_path in loaded project files (#2110)

A .jedi/project.json can be part of a checked out repository, so honouring its environment_path let an untrusted file point Jedi at a binary to execute. Rather than trying to gate that binary (the ownership heuristic in _is_unix_safe_simple is meaningless on Windows, where st_uid is always 0), drop environment_path from loaded project files entirely, the same way load_unsafe_extensions is already ignored. It stays available when a Project is constructed directly by the user.

jedi/api/project.py

@@ -63,9 +63,6 @@ class Project:
     Additionally there are functions to search a whole project.
     """
     _environment = None
-    # Set for projects loaded from a ``.jedi/project.json``. That file can be
-    # part of a checked out repository, so it is not trusted to run binaries.
-    _loaded_from_file = False
 
     @staticmethod
     def _get_config_folder_path(base_path):
@@ -90,12 +87,14 @@ class Project:
 
         if version == 1:
             # A code base must not be able to enable the loading of its own
-            # extensions, see the docs about security.
+            # extensions or point Jedi at a binary to execute, see the docs
+            # about security. The project file can be part of a checked out
+            # repository, so these settings are ignored for loaded projects.
             if data.pop('load_unsafe_extensions', False):
                 debug.warning('load_unsafe_extensions is ignored for loaded projects')
-            project = cls(**data)
-            project._loaded_from_file = True
-            return project
+            if data.pop('environment_path', None) is not None:
+                debug.warning('environment_path is ignored for loaded projects')
+            return cls(**data)
         else:
             raise WrongVersion(
                 "The Jedi version of this project seems newer than what we can handle."
@@ -107,7 +106,6 @@ class Project:
         """
         data = dict(self.__dict__)
         data.pop('_environment', None)
-        data.pop('_loaded_from_file', None)
         data.pop('_django', None)  # TODO make django setting public?
         data = {k.lstrip('_'): v for k, v in data.items()}
         data['path'] = str(data['path'])
@@ -252,10 +250,10 @@ class Project:
     def get_environment(self):
         if self._environment is None:
             if self._environment_path is not None:
-                # An environment path from a loaded project file is checked
-                # like a scanned virtualenv, see find_virtualenvs.
+                # environment_path can only be set by the user directly, it is
+                # never loaded from a project file, so it is trusted.
                 self._environment = create_environment(
-                    self._environment_path, safe=self._loaded_from_file)
+                    self._environment_path, safe=False)
             else:
                 self._environment = get_cached_default_environment()
         return self._environment