From 2c91896070a0580eaa7ad233952e2e44c72eb0e6 Mon Sep 17 00:00:00 2001
From: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
Date: Wed, 12 Nov 2025 12:02:50 +0000
Subject: [PATCH] Run trial tests on Python 3.14 in PRs (#19135)

---
 .ci/scripts/calculate_jobs.py | 39 +++++++++++++++++++++--------------
 changelog.d/19135.misc        |  1 +
 2 files changed, 25 insertions(+), 15 deletions(-)
 create mode 100644 changelog.d/19135.misc

diff --git a/.ci/scripts/calculate_jobs.py b/.ci/scripts/calculate_jobs.py
index 87fbc7a266..810d41bfd4 100755
--- a/.ci/scripts/calculate_jobs.py
+++ b/.ci/scripts/calculate_jobs.py
@@ -35,46 +35,55 @@ IS_PR = os.environ["GITHUB_REF"].startswith("refs/pull/")
 
 # First calculate the various trial jobs.
 #
-# For PRs, we only run each type of test with the oldest Python version supported (which
-# is Python 3.10 right now)
+# For PRs, we only run each type of test with the oldest and newest Python
+# version that's supported. The oldest version ensures we don't accidentally
+# introduce syntax or code that's too new, and the newest ensures we don't use
+# code that's been dropped in the latest supported Python version.
 
 trial_sqlite_tests = [
     {
         "python-version": "3.10",
         "database": "sqlite",
         "extras": "all",
-    }
+    },
+    {
+        "python-version": "3.14",
+        "database": "sqlite",
+        "extras": "all",
+    },
 ]
 
 if not IS_PR:
+    # Otherwise, check all supported Python versions.
+    #
+    # Avoiding running all of these versions on every PR saves on CI time.
     trial_sqlite_tests.extend(
         {
             "python-version": version,
             "database": "sqlite",
             "extras": "all",
         }
-        for version in ("3.11", "3.12", "3.13", "3.14")
+        for version in ("3.11", "3.12", "3.13")
     )
 
+# Only test postgres against the earliest and latest Python versions that we
+# support in order to save on CI time.
 trial_postgres_tests = [
     {
         "python-version": "3.10",
         "database": "postgres",
         "postgres-version": "13",
         "extras": "all",
-    }
+    },
+    {
+        "python-version": "3.14",
+        "database": "postgres",
+        "postgres-version": "17",
+        "extras": "all",
+    },
 ]
 
-if not IS_PR:
-    trial_postgres_tests.append(
-        {
-            "python-version": "3.14",
-            "database": "postgres",
-            "postgres-version": "17",
-            "extras": "all",
-        }
-    )
-
+# Ensure that Synapse passes unit tests even with no extra dependencies installed.
 trial_no_extra_tests = [
     {
         "python-version": "3.10",
diff --git a/changelog.d/19135.misc b/changelog.d/19135.misc
new file mode 100644
index 0000000000..8d0c56a7ec
--- /dev/null
+++ b/changelog.d/19135.misc
@@ -0,0 +1 @@
+Run trial tests on Python 3.14 for PRs.
\ No newline at end of file