feat: start new instances on python 3.14 rather than 3.15

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Dockerfile

@@ -158,7 +158,7 @@ ARG features=""
 # (PyVAlias::default() in the backend), NEW_INSTANCE_PY the one new instances start on
 # (PyVAlias::NEW_INSTANCE). When raising the latter, keep installing every earlier value.
 ARG LATEST_STABLE_PY=3.12
-ARG NEW_INSTANCE_PY=3.15
+ARG NEW_INSTANCE_PY=3.14
 ENV UV_PYTHON_INSTALL_DIR=/tmp/windmill/cache/py_runtime
 ENV UV_PYTHON_PREFERENCE=only-managed
 

backend/windmill-common/src/worker.rs

@@ -2917,7 +2917,7 @@ impl PyVAlias {
     /// What the server writes into `instance_python_version` when it initializes an instance.
     /// Raising it also means the images must keep preinstalling every earlier value, or
     /// instances that started on one download their runtime on first use.
-    pub const NEW_INSTANCE: PyVAlias = PyVAlias::Py315;
+    pub const NEW_INSTANCE: PyVAlias = PyVAlias::Py314;
 
     pub fn all<T: From<PyVAlias>>() -> Vec<T> {
         use PyVAlias::*;

docker/DockerfileSlim

@@ -30,7 +30,7 @@ FROM ${DEBIAN_IMAGE}
 
 ARG APP=/usr/src/app
 ARG LATEST_STABLE_PY=3.12.13
-ARG NEW_INSTANCE_PY=3.15.0
+ARG NEW_INSTANCE_PY=3.14.8
 
 # UV configuration
 ENV UV_CACHE_DIR=/tmp/windmill/cache/uv

docker/DockerfileSlimEe

@@ -30,7 +30,7 @@ FROM ${DEBIAN_IMAGE}
 
 ARG APP=/usr/src/app
 ARG LATEST_STABLE_PY=3.12.13
-ARG NEW_INSTANCE_PY=3.15.0
+ARG NEW_INSTANCE_PY=3.14.8
 
 # UV configuration
 ENV UV_CACHE_DIR=/tmp/windmill/cache/uv