add support for sphinx 9.0

Author: mathiasertl

.github/workflows/tests.yml

@@ -14,7 +14,7 @@ jobs:
       matrix:
         os: [ ubuntu-latest ]
         python-version: [ "3.10", "3.11", "3.12", "3.13", "3.14" ]
-        sphinx-version: [ "8.1", "8.2" ]
+        sphinx-version: [ "8.1", "8.2", "9.0" ]
         exclude:
           - python-version: "3.10"
             sphinx-version: "8.2"

.readthedocs.yaml

@@ -21,7 +21,7 @@ build:
       - asdf install uv 0.9.2
       - asdf global uv 0.9.2
     install:
-      - uv sync
+      - uv sync --group dev --group rtd
     pre_build:
       - ./fetch_swagger.sh
       - uv run generate-schema.py

docs/conf.py

@@ -18,12 +18,18 @@
 # https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
 
 extensions = [
-    "sphinx_rtd_theme",
     "sphinxcontrib.spelling",
     "structured_tutorials.sphinx",
     "sphinx_inline_tabs",
 ]
-html_theme = "sphinx_rtd_theme"
+
+try:
+    import sphinx_rtd_theme
+
+    extensions.append("sphinx_rtd_theme")
+    html_theme = "sphinx_rtd_theme"
+except ImportError:
+    pass
 
 DOC_ROOT = Path(__file__).parent
 structured_tutorials_root = DOC_ROOT / "tutorials"

pyproject.toml

@@ -122,6 +122,7 @@ conflicts = [
         { group = "Sphinx8.2" },
         { group = "Sphinx9.0" },
     ],
+    [ { group = "Sphinx9.0" }, { group = "rtd" } ]
 ]
 
 [dependency-groups]
@@ -134,14 +135,15 @@ dev = [
     "pytest-random-order>=1.1.1",
     "pytest-subprocess>=1.5.3",
     "ruff>=0.11.10",
-    "sphinx-rtd-theme>=3.0.2",
     "sphinxcontrib-spelling>=8.0.1",
     "types-colorama>=0.4.15.20250801",
     "types-docutils>=0.21.0.20250604",
     "types-pyyaml>=6.0.12.20250516",
 ]
+rtd = [
+    "sphinx-rtd-theme>=3.0.2",
+]
 
 "Sphinx8.1" = [ "Sphinx~=8.1.0;python_version<'3.11'" ]
 "Sphinx8.2" = [ "Sphinx~=8.2.0;python_version>='3.11'" ]
-# Not working b/c of RTD theme ATM
-#"Sphinx9.0" = [ "Sphinx~=9.0.0;python_version>='3.11'" ]
+"Sphinx9.0" = [ "Sphinx~=9.0.0;python_version>='3.11'" ]