Update for Python 3.14, NEP-29, pyprojct tidying

.github/workflows/python.yml

@@ -26,7 +26,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.10", "3.11", "3.12"]
+        python-version: ["3.12", "3.13", "3.14"]
 
     steps:
       - uses: actions/checkout@v6
@@ -41,7 +41,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
-          pip install -r requirements_dev.txt dist/*.whl
+          pip install --group dev dist/*.whl
       - name: Test with pytest
         run: |
           pytest tests

pyproject.toml

@@ -19,7 +19,7 @@ classifiers = [
     "Topic :: Software Development :: Libraries :: Python Modules",
 ]
 license = { text = "BSD-3-Clause" }
-requires-python = ">=3.10"
+requires-python = ">=3.12"
 dependencies = [
     "bidict", 
     "pika",
@@ -39,6 +39,16 @@ Bug-Tracker = "https://github.com/DiamondLightSource/python-workflows/issues"
 [project.optional-dependencies]
 prometheus = ["prometheus-client"]
 
+[dependency-groups]
+dev = [
+    "prometheus-client",
+    "pytest",
+    "pytest-cov",
+    "pytest-mock",
+    "pytest-timeout",
+    "websocket-client",
+]
+
 [project.entry-points."libtbx.dispatcher.script"]
 "workflows.validate_recipe" = "workflows.validate_recipe"
 

src/workflows/frontend/__init__.py

@@ -16,6 +16,12 @@
 
 basestring = (str, bytes)
 
+# Pin the fork start method: service instances carry pipes and transport
+# state that aren't pickleable, so spawn/forkserver (the 3.14+ default on
+# Linux) can't serialize them. fork is deprecated upstream and will
+# eventually need a real refactor.
+multiprocessing.set_start_method("fork", force=True)
+
 
 class Frontend:
     """The frontend class encapsulates the actual service. It controls the