DOC Add policy to upper bound build deps in maintainers page (#31345)

jeremiedbb · lucyleeow · web-flow · commit ce4a40ffae50 · 2025-05-13T15:30:55.000+02:00
Co-authored-by: Lucy Liu &lt;jliu176@gmail.com&gt;
diff --git a/doc/developers/maintainer.rst.template b/doc/developers/maintainer.rst.template
@@ -121,6 +121,9 @@ Reference Steps
         * [ ] Update the sklearn dev0 version in main branch
         {%- endif %}
         * [ ] Set the version number in the release branch
+        {% if key == "rc" -%}
+        * [ ] Set an upper bound on build dependencies in the release branch
+        {%- endif %}
         * [ ] Generate the changelog in the release branch
         * [ ] Check that the wheels for the release can be built successfully
         * [ ] Merge the PR with `[cd build]` commit message to upload wheels to the staging repo
@@ -162,6 +165,17 @@ Reference Steps
     - In the release branch, change the version number `__version__` in
       `sklearn/__init__.py` to `{{ version_full }}`.
 
+    {% if key == "rc" %}
+    - Still in the release branch, set or update the upper bound on the build
+      dependencies in the `[build-system]` section of `pyproject.toml`. The goal is to
+      prevent future backward incompatible releases of the dependencies to break the
+      build in the maintenance branch.
+
+      The upper bounds should match the latest already-released minor versions of the
+      dependencies and should allow future micro (bug-fix) versions. For instance, if
+      numpy 2.2.5 is the most recent version, its upper bound should be set to <2.3.0.
+    {% endif %}
+
     - In the release branch, generate the changelog for the incoming version, i.e.,
       `doc/whats_new/{{ version_short }}.rst`.
       {%- if key == "rc" %}
