Revert "sphinx: 5.3.0 -> 6.1.3"

This reverts commit 96fc61bb781dbf604f303088fbeca7fe56512426.

Sphinx versions >=6.0 fail to import extensions, which represents a
severe regression. Details about this issue have been posted at
https://github.com/NixOS/nixpkgs/pull/210338#issuecomment-1447063024.

pkgs/development/python-modules/sphinx/0001-test-images-Use-normalization-equivalent-character.patch

@@ -0,0 +1,35 @@
+From 181617387841b695ee77b162babf9fb177002fcb Mon Sep 17 00:00:00 2001
+From: toonn <toonn@toonn.io>
+Date: Mon, 20 Sep 2021 11:39:46 +0200
+Subject: [PATCH] test-images: Use normalization equivalent character
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+One of the test images used a combining character `ä` that can be
+encoded multiple ways. This means the file's name can end up encoded
+differently depending on whether/which normal form the filesystem uses.
+
+For Nix this causes a different hash for a FOD depending on the
+filesystem where it is evaluated. This is problematic because hashes
+fail to match up when evaluating the FOD across multiple platforms.
+---
+ tests/roots/test-images/index.rst | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/tests/roots/test-images/index.rst b/tests/roots/test-images/index.rst
+index 14a2987..219842e 100644
+--- a/tests/roots/test-images/index.rst
++++ b/tests/roots/test-images/index.rst
+@@ -13,7 +13,7 @@ test-image
+ 
+    The caption of img
+ 
+-.. image:: testimäge.png
++.. image:: testimæge.png
+ 
+ .. image:: rimg.png
+    :target: https://www.sphinx-doc.org/
+-- 
+2.17.2 (Apple Git-113)
+

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

@@ -3,6 +3,7 @@
 , buildPythonPackage
 , pythonOlder
 , fetchFromGitHub
+, fetchpatch
 
 # nativeBuildInputs
 , flit-core
@@ -31,33 +32,27 @@
 , cython
 , html5lib
 , pytestCheckHook
+, typed-ast
 }:
 
 buildPythonPackage rec {
   pname = "sphinx";
-  version = "6.1.3";
+  version = "5.3.0";
   format = "pyproject";
 
-  disabled = pythonOlder "3.8";
+  disabled = pythonOlder "3.6";
 
   src = fetchFromGitHub {
     owner = "sphinx-doc";
     repo = pname;
     rev = "refs/tags/v${version}";
-    /* One of the test images used a combining character `ä` that can be
-       encoded multiple ways. This means the file's name can end up encoded
-       differently depending on whether/which normal form the filesystem uses.
-
-       For Nix this causes a different hash for a FOD depending on the
-       filesystem where it is evaluated. This is problematic because hashes
-       fail to match up when evaluating the FOD across multiple platforms.
-    */
+    hash = "sha256-80bVg1rfBebgSOKbWkzP84vpm39iLgM8lWlVD64nSsQ=";
     postFetch = ''
       cd $out
-      mv tests/roots/test-images/{testimäge,testimæge}.png
-      sed -i 's/testimäge/testimæge/g' tests/{test_build*.py,roots/test-images/index.rst}
+      mv tests/roots/test-images/testimäge.png \
+        tests/roots/test-images/testimæge.png
+      patch -p1 < ${./0001-test-images-Use-normalization-equivalent-character.patch}
     '';
-    hash = "sha256-ClKAB+oQ0sdV/mssfXEkgpqbzhT3ybXPeqjQjbxqbrY=";
   };
 
   nativeBuildInputs = [
@@ -93,10 +88,12 @@ buildPythonPackage rec {
     cython
     html5lib
     pytestCheckHook
+  ] ++ lib.optionals (pythonOlder "3.8") [
+    typed-ast
   ];
 
   preCheck = ''
-    export HOME=$TMPDIR
+    export HOME=$(mktemp -d)
   '';
 
   disabledTests = [