From b09ebcbef6de8a3fce0390d37b9f498e3db36b69 Mon Sep 17 00:00:00 2001
From: dgtlmoon <dgtlmoon@gmail.com>
Date: Mon, 2 Mar 2026 11:28:52 +0100
Subject: [PATCH] Python 3.14 CI test and support (#3941)

---
 .github/workflows/test-only.yml               | 11 ++++++-
 .../test-stack-reusable-workflow.yml          | 14 ++++++++-
 changedetectionio/tests/conftest.py           | 29 +++++++++++++++++++
 3 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/test-only.yml b/.github/workflows/test-only.yml
index 3de8692b..b2666f10 100644
--- a/.github/workflows/test-only.yml
+++ b/.github/workflows/test-only.yml
@@ -52,4 +52,13 @@ jobs:
     uses: ./.github/workflows/test-stack-reusable-workflow.yml
     with:
       python-version: '3.13'
-      skip-pypuppeteer: true
\ No newline at end of file
+      skip-pypuppeteer: true
+
+
+  test-application-3-14:
+    #if: github.event_name == 'push' && github.ref == 'refs/heads/master'
+    needs: lint-code
+    uses: ./.github/workflows/test-stack-reusable-workflow.yml
+    with:
+      python-version: '3.14'
+      skip-pypuppeteer: false
diff --git a/.github/workflows/test-stack-reusable-workflow.yml b/.github/workflows/test-stack-reusable-workflow.yml
index 080247d0..15aabd2b 100644
--- a/.github/workflows/test-stack-reusable-workflow.yml
+++ b/.github/workflows/test-stack-reusable-workflow.yml
@@ -706,7 +706,19 @@ jobs:
       - name: Check upgrade works without error
         run: |
           echo "=== Testing upgrade path from 0.49.1 to ${{ github.ref_name }} (${{ github.sha }}) ==="
-
+          sudo apt-get update && sudo apt-get install -y --no-install-recommends \
+              g++ \
+              gcc \
+              libc-dev \
+              libffi-dev \
+              libjpeg-dev \
+              libssl-dev \
+              libxslt-dev \
+              make \
+              patch \
+              pkg-config \
+              zlib1g-dev
+          
           # Checkout old version and create datastore
           git checkout 0.49.1
           python3 -m venv .venv
diff --git a/changedetectionio/tests/conftest.py b/changedetectionio/tests/conftest.py
index 6da101c4..8972ba8e 100644
--- a/changedetectionio/tests/conftest.py
+++ b/changedetectionio/tests/conftest.py
@@ -2,6 +2,7 @@
 import psutil
 import time
 from threading import Thread
+import multiprocessing
 
 import pytest
 import arrow
@@ -191,6 +192,34 @@ def cleanup(datastore_path):
             if os.path.isfile(f):
                 os.unlink(f)
 
+def pytest_configure(config):
+    """Configure pytest environment before tests run.
+
+    CRITICAL: Set multiprocessing start method to 'fork' for Python 3.14+ compatibility.
+
+    Python 3.14 changed the default start method from 'fork' to 'forkserver' on Linux.
+    The forkserver method requires all objects to be picklable, but pytest-flask's
+    LiveServer uses nested functions that can't be pickled.
+
+    Setting 'fork' explicitly:
+    - Maintains compatibility with Python 3.10-3.13 (where 'fork' was already default)
+    - Fixes Python 3.14 pickling errors
+    - Only affects Unix-like systems (Windows uses 'spawn' regardless)
+
+    See: https://github.com/python/cpython/issues/126831
+    See: https://docs.python.org/3/whatsnew/3.14.html
+    """
+    # Only set if not already set (respects existing configuration)
+    if multiprocessing.get_start_method(allow_none=True) is None:
+        try:
+            # 'fork' is available on Unix-like systems (Linux, macOS)
+            # On Windows, this will have no effect as 'spawn' is the only option
+            multiprocessing.set_start_method('fork', force=False)
+            logger.debug("Set multiprocessing start method to 'fork' for Python 3.14+ compatibility")
+        except (ValueError, RuntimeError):
+            # Already set, not available on this platform, or context already created
+            pass
+
 def pytest_addoption(parser):
     """Add custom command-line options for pytest.