python3.pkgs.jedi: fix compatibility with parso

The current version is fundamentally broken as tested with
python-language-server because parso now uses Path instead of str
in many instances.

Backporting of the fixes is not trivial and likely breaks more stuff
than it fixes due to other refactorings in jedi, hence using a recent
commit in master seems more reasonably.

pkgs/development/python-modules/jedi/default.nix

@@ -1,24 +1,23 @@
-{ stdenv, buildPythonPackage, fetchPypi, pytest, glibcLocales, tox, pytestcov, parso }:
+{ stdenv, buildPythonPackage, fetchFromGitHub, fetchPypi, pytest, glibcLocales, tox, pytestcov, parso }:
 
 buildPythonPackage rec {
   pname = "jedi";
-  version = "0.17.2";
-
-  src = fetchPypi {
-    inherit pname version;
-    sha256 = "86ed7d9b750603e4ba582ea8edc678657fb4007894a12bcf6f4bb97892f31d20";
+  # switch back to stable version on the next release.
+  # current stable is incompatible with parso
+  version = "2020-08-06";
+
+  src = fetchFromGitHub {
+    owner = "davidhalter";
+    repo = "jedi";
+    rev = "216f976fd5cab7a460e5d287e853d11759251e52";
+    sha256 = "1kb2ajzigadl95pnwglg8fxz9cvpg9hx30hqqj91jkgrc7djdldj";
+    fetchSubmodules = true;
   };
 
   checkInputs = [ pytest glibcLocales tox pytestcov ];
 
   propagatedBuildInputs = [ parso ];
 
-  # remove next bump, >=0.17.2, already fixed in master
-  prePatch = ''
-    substituteInPlace requirements.txt \
-      --replace "parso>=0.7.0,<0.8.0" "parso"
-  '';
-
   checkPhase = ''
     LC_ALL="en_US.UTF-8" py.test test
   '';