Merge branch 'master' into PYTHON-5814

Author: sleepyStick

.evergreen/config.yml

@@ -45,6 +45,17 @@ post:
   - func: "cleanup"
 
 tasks:
+  - name: linkcheck
+    commands:
+      - command: subprocess.exec
+        type: test
+        params:
+          binary: bash
+          args:
+            - .evergreen/just.sh
+            - docs-linkcheck
+          working_dir: src
+
   - name: resync_specs
     commands:
       - command: subprocess.exec
@@ -56,6 +67,14 @@ tasks:
           working_dir: src
 
 buildvariants:
+  - name: linkcheck
+    display_name: "Link Check"
+    run_on: rhel80-small
+    cron: '0 0 * * *'
+    patchable: true
+    tasks:
+      - name: linkcheck
+
   - name: resync_specs
     display_name: "Resync Specs"
     run_on: rhel80-small

.evergreen/generated_configs/tasks.yml

@@ -4802,22 +4802,20 @@ tasks:
       - python-3.13
       - standalone-noauth-nossl
       - noauth
-  - name: test-non-standard-latest-python3.14t-noauth-ssl-replica-set-cov
+  - name: test-non-standard-latest-python3.14t-noauth-ssl-replica-set
     commands:
       - func: run server
         vars:
           AUTH: noauth
           SSL: ssl
           TOPOLOGY: replica_set
           VERSION: latest
-          COVERAGE: "1"
       - func: run tests
         vars:
           AUTH: noauth
           SSL: ssl
           TOPOLOGY: replica_set
           VERSION: latest
-          COVERAGE: "1"
           TOOLCHAIN_VERSION: 3.14t
     tags:
       - test-non-standard
@@ -4826,7 +4824,6 @@ tasks:
       - replica_set-noauth-ssl
       - noauth
       - free-threaded
-      - pr
   - name: test-non-standard-latest-pypy3.11-noauth-ssl-replica-set
     commands:
       - func: run server
@@ -4873,30 +4870,50 @@ tasks:
       - sharded_cluster-auth-ssl
       - auth
       - pr
-  - name: test-non-standard-latest-python3.13-noauth-nossl-standalone-cov
+      - cov
+  - name: test-non-standard-latest-python3.14-auth-ssl-sharded-cluster
+    commands:
+      - func: run server
+        vars:
+          AUTH: auth
+          SSL: ssl
+          TOPOLOGY: sharded_cluster
+          VERSION: latest
+      - func: run tests
+        vars:
+          AUTH: auth
+          SSL: ssl
+          TOPOLOGY: sharded_cluster
+          VERSION: latest
+          TOOLCHAIN_VERSION: "3.14"
+    tags:
+      - test-non-standard-no-cov
+      - server-latest
+      - python-3.14
+      - sharded_cluster-auth-ssl
+      - auth
+      - pr
+  - name: test-non-standard-latest-python3.13-noauth-nossl-standalone
     commands:
       - func: run server
         vars:
           AUTH: noauth
           SSL: nossl
           TOPOLOGY: standalone
           VERSION: latest
-          COVERAGE: "1"
       - func: run tests
         vars:
           AUTH: noauth
           SSL: nossl
           TOPOLOGY: standalone
           VERSION: latest
-          COVERAGE: "1"
           TOOLCHAIN_VERSION: "3.13"
     tags:
       - test-non-standard
       - server-latest
       - python-3.13
       - standalone-noauth-nossl
       - noauth
-      - pr
   - name: test-non-standard-rapid-python3.11-noauth-ssl-replica-set
     commands:
       - func: run server

.evergreen/generated_configs/variants.yml

@@ -193,7 +193,8 @@ buildvariants:
     tags: [encryption_tag]
   - name: encryption-macos
     tasks:
-      - name: .test-non-standard !.pypy
+      - name: .test-non-standard !.pypy !.cov
+      - name: .test-non-standard-no-cov !.pypy
     display_name: Encryption macOS
     run_on:
       - macos-14
@@ -203,7 +204,8 @@ buildvariants:
     tags: [encryption_tag]
   - name: encryption-win64
     tasks:
-      - name: .test-non-standard !.pypy
+      - name: .test-non-standard !.pypy !.cov
+      - name: .test-non-standard-no-cov !.pypy
     display_name: Encryption Win64
     run_on:
       - windows-2022-latest-small
@@ -224,7 +226,8 @@ buildvariants:
     tags: [encryption_tag]
   - name: encryption-crypt_shared-macos
     tasks:
-      - name: .test-non-standard !.pypy
+      - name: .test-non-standard !.pypy !.cov
+      - name: .test-non-standard-no-cov !.pypy
     display_name: Encryption crypt_shared macOS
     run_on:
       - macos-14
@@ -235,7 +238,8 @@ buildvariants:
     tags: [encryption_tag]
   - name: encryption-crypt_shared-win64
     tasks:
-      - name: .test-non-standard !.pypy
+      - name: .test-non-standard !.pypy !.cov
+      - name: .test-non-standard-no-cov !.pypy
     display_name: Encryption crypt_shared Win64
     run_on:
       - windows-2022-latest-small

.evergreen/scripts/generate_config.py

@@ -132,7 +132,11 @@ def get_encryption_expansions(encryption):
         display_name = get_variant_name(encryption, host, **expansions)
         tasks = [".test-non-standard"]
         if host != "rhel8":
-            tasks = [".test-non-standard !.pypy"]
+            # Exclude PyPy (not tested with encryption on macOS/win64) and coverage tasks
+            # (encryption suites exceed the 60-min timeout with coverage overhead on macOS/win64).
+            # Also include the non-coverage companion tasks (test-non-standard-no-cov) which
+            # carry the "latest" server tasks without COVERAGE=1.
+            tasks = [".test-non-standard !.pypy !.cov", ".test-non-standard-no-cov !.pypy"]
         variant = create_variant(
             tasks,
             display_name,
@@ -644,8 +648,9 @@ def create_test_non_standard_tasks():
     tasks = []
     task_combos = set()
     # For each version and topology, rotate through the CPythons.
+    # Only the sharded_cluster topology runs on PRs to keep patch build size manageable.
     for (version, topology), python in zip_cycle(list(product(ALL_VERSIONS, TOPOLOGIES)), CPYTHONS):
-        pr = version == "latest"
+        pr = version == "latest" and topology == "sharded_cluster"
         task_combos.add((version, topology, python, pr))
     # For each PyPy and topology, rotate through the MongoDB versions.
     for (python, topology), version in zip_cycle(list(product(PYPYS, TOPOLOGIES)), ALL_VERSIONS):
@@ -670,12 +675,33 @@ def create_test_non_standard_tasks():
             expansions["TEST_MIN_DEPS"] = "1"
         elif pr:
             expansions["COVERAGE"] = "1"
+            tags.append("cov")
         name = get_task_name("test-non-standard", python=python, **expansions)
         server_func = FunctionCall(func="run server", vars=expansions)
         test_vars = expansions.copy()
         test_vars["TOOLCHAIN_VERSION"] = python
         test_func = FunctionCall(func="run tests", vars=test_vars)
         tasks.append(EvgTask(name=name, tags=tags, commands=[server_func, test_func]))
+        # For each coverage task, also emit a non-coverage companion so that
+        # macOS/Win64 encryption variants (which filter out .cov due to timeout
+        # constraints) still have a "latest" task to activate in patch builds.
+        if pr and "cov" in tags:
+            nc_expansions = {k: v for k, v in expansions.items() if k != "COVERAGE"}
+            # Use a distinct primary tag so companions are not selected by existing
+            # ".test-non-standard" selectors (e.g. load-balancer, PyOpenSSL variants).
+            nc_tags = [
+                "test-non-standard-no-cov" if t == "test-non-standard" else t
+                for t in tags
+                if t != "cov"
+            ]
+            nc_name = get_task_name("test-non-standard", python=python, **nc_expansions)
+            nc_server_func = FunctionCall(func="run server", vars=nc_expansions)
+            nc_test_vars = nc_expansions.copy()
+            nc_test_vars["TOOLCHAIN_VERSION"] = python
+            nc_test_func = FunctionCall(func="run tests", vars=nc_test_vars)
+            tasks.append(
+                EvgTask(name=nc_name, tags=nc_tags, commands=[nc_server_func, nc_test_func])
+            )
     return tasks
 
 

.github/workflows/test-python.yml

@@ -46,6 +46,9 @@ jobs:
       - name: Run typecheck
         run: |
           just typing
+      - name: Run synchro smoke test
+        run: |
+          uv run --extra test --with unasync pytest tools/test_synchro.py -v --override-ini="addopts="
       - run: |
           sudo apt-get install -y cppcheck
       - run: |
@@ -154,27 +157,6 @@ jobs:
       - name: Build docs
         run: just docs
 
-  linkcheck:
-    name: Link Check
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v6.0.3
-        with:
-          persist-credentials: false
-      - name: Install uv
-        uses: astral-sh/setup-uv@fac544c07dec837d0ccb6301d7b5580bf5edae39 # v8.2.0
-        with:
-          enable-cache: true
-          python-version: "3.10"
-      - name: Install just
-        run: uv tool install rust-just
-      - name: Install dependencies
-        run: just install
-      - name: Build docs
-        run: just docs-linkcheck
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
   typing:
     name: Typing Tests
     runs-on: ubuntu-latest

.gitignore

@@ -30,6 +30,7 @@ expansion.yml
 .evergreen/scripts/test-env.sh
 specifications/
 results.json
+.synchro-modified
 .evergreen/atlas_x509_dev_client_certificate.pem
 
 # Lambda temp files

.pre-commit-config.yaml

@@ -18,25 +18,36 @@ repos:
     exclude: .patch
     exclude_types: [json]
 
-- repo: https://github.com/astral-sh/ruff-pre-commit
-  # Ruff version.
-  rev: v0.15.16
+- repo: local
   hooks:
     - id: ruff
-      args: ["--fix", "--show-fixes"]
+      name: ruff
+      entry: uv run --group lint ruff check --fix --show-fixes
+      language: system
+      types_or: [python, pyi]
+      require_serial: true
     - id: ruff-format
+      name: ruff-format
+      entry: uv run --group lint ruff format
+      language: system
+      types_or: [python, pyi]
+      require_serial: true
 
 - repo: local
   hooks:
     - id: synchro
       name: synchro
-      entry: bash ./tools/synchro.sh
-      language: python
+      entry: uv run --group unasync ./tools/synchro.py
+      language: system
+      require_serial: true
+      always_run: true
+    - id: synchro-stage-files
+      name: synchro-stage-files
+      entry: bash -c 'if [ -s .synchro-modified ]; then xargs git add < .synchro-modified || true; fi'
+      language: system
       require_serial: true
-      fail_fast: true
-      additional_dependencies:
-        - ruff==0.15.16
-        - unasync
+      always_run: true
+      pass_filenames: false
 
 - repo: https://github.com/adamchainz/blacken-docs
   rev: "1.16.0"

doc/changelog.rst

@@ -1,6 +1,14 @@
 Changelog
 =========
 
+Changes in Version 4.18.0
+-------------------------
+
+- Improved TLS connection performance by reusing TLS sessions across connections
+  to the same server, avoiding a full handshake on each new connection.
+  Session resumption is supported on all Python versions for synchronous clients
+  and on Python 3.11+ for async clients.
+
 Changes in Version 4.17.0 (2026/04/20)
 --------------------------------------
 

doc/conf.py

@@ -98,9 +98,8 @@
 linkcheck_workers = 1
 # Give slow redirects more time before retrying.
 linkcheck_timeout = 60
-
-# Ignore anchors in links since they may not be added to the page right away.
-linkcheck_anchors_ignore_for_url = [r"https://github.com/.*"]
+# Ignore anchors in links
+linkcheck_anchors = False
 
 # Pass GitHub token to avoid rate-limiting on GitHub links.
 if github_token := os.environ.get("GITHUB_TOKEN"):

justfile

@@ -16,6 +16,10 @@ default:
 resync:
  @uv sync --quiet
 
+[private]
+run-synchro:
+    uv run --group unasync ./tools/synchro.py
+
 # Set up the development environment
 install:
    bash .evergreen/scripts/setup-dev-env.sh
@@ -66,7 +70,7 @@ lint-manual *args="": && resync
 
 # Run pytest (e.g. just test test/test_uri_parser.py)
 [group('test')]
-test *args="-v --durations=5 --maxfail=10": && resync
+test *args="-v --durations=5 --maxfail=10": run-synchro && resync
     #!/usr/bin/env bash
     set -euo pipefail
     uv run ${USE_ACTIVE_VENV:+--active} --extra test python -m pytest {{args}}
@@ -79,7 +83,7 @@ test-numpy *args="": && resync
 
 # Run tests via the Evergreen test runner script
 [group('test')]
-run-tests *args: && resync
+run-tests *args: run-synchro && resync
     bash ./.evergreen/run-tests.sh {{args}}
 
 # Set up the test environment (auth, TLS, etc.)