python3.pkgs.jinja2: build offline documentation

pkgs/applications/misc/privacyidea/default.nix

@@ -52,7 +52,7 @@ let
         doCheck = false;
       });
       # Required by flask-1.1
-      jinja2 = super.jinja2.overridePythonAttrs (old: rec {
+      jinja2 = (super.jinja2.override { enableDocumentation = false; }).overridePythonAttrs (old: rec {
         version = "2.11.3";
         src = old.src.override {
           inherit version;

pkgs/development/python-modules/jinja2/default.nix

@@ -6,11 +6,17 @@
 , babel
 , markupsafe
 , pytestCheckHook
+, sphinxHook
+, pallets-sphinx-themes
+, sphinxcontrib-log-cabinet
+, sphinx-issues
+, enableDocumentation ? true
 }:
 
 buildPythonPackage rec {
   pname = "Jinja2";
   version = "3.1.2";
+  outputs = [ "out" ] ++ lib.optional enableDocumentation "doc";
 
   disabled = pythonOlder "3.7";
 
@@ -19,11 +25,20 @@ buildPythonPackage rec {
     hash = "sha256-MTUacCpAip51laj8YVD8P0O7a/fjGXcMvA2535Q36FI=";
   };
 
+  patches = lib.optionals enableDocumentation [ ./patches/import-order.patch ];
+
   propagatedBuildInputs = [
     babel
     markupsafe
   ];
 
+  nativeBuildInputs = lib.optionals enableDocumentation [
+    sphinxHook
+    sphinxcontrib-log-cabinet
+    pallets-sphinx-themes
+    sphinx-issues
+  ];
+
   # Multiple tests run out of stack space on 32bit systems with python2.
   # See https://github.com/pallets/jinja/issues/1158
   doCheck = !stdenv.is32bit;

pkgs/development/python-modules/jinja2/patches/import-order.patch

@@ -0,0 +1,27 @@
+Sphinx changed something between sphinx=4.5.0 and sphinx=5.3 that broke
+"sphinxcontrib.log_cabinet" plugin.
+
+When Sphinx tries to importlib.import_module("sphinxcontrib.log_cabinet"), it
+has couple other sphinxcontrib.* libraries in sys.path, and they seem to cause
+conflict. So here I purge sys.path from sphixcontrib-related things, import
+log_cabinet and put everything back, so when Sphinx will do "import_module",
+"sphinxcontrib.log_cabinet" will be already imported and cached.
+
+All this is quite hacky, but we are talking about merely building documentation
+here. If resulting html looks good, what happened in Nix sandbox stays in Nix
+sandbox.
+
+--- a/docs/conf.py	1970-01-01 00:00:00.000000000 -0000
++++ b/docs/conf.py	1970-01-01 00:00:00.000000000 -0000
+@@ -1,5 +1,12 @@
+ from pallets_sphinx_themes import get_version
+ from pallets_sphinx_themes import ProjectLink
++import importlib
++import sys
++
++saved_path = sys.path
++sys.path = [x for x in sys.path if "sphinxcontrib" not in x or "cabinet" in x]
++import sphinxcontrib.log_cabinet
++sys.path = saved_path
+ 
+ # Project --------------------------------------------------------------

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

@@ -64,7 +64,7 @@ buildPythonPackage rec {
     alabaster
     docutils
     imagesize
-    jinja2
+    (jinja2.override { enableDocumentation = false; })
     packaging
     pygments
     requests