Run trial tests on Python 3.14 in PRs (#19135)

Author: anoadragon453

.ci/scripts/calculate_jobs.py

@@ -35,46 +35,55 @@ def set_output(key: str, value: str):
 
 # 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",

changelog.d/19135.misc

@@ -0,0 +1 @@
+Run trial tests on Python 3.14 for PRs.