Remove support for Python 3.7 (#15851)

Fix https://github.com/matrix-org/synapse/issues/15836

12 files changed, 55 insertions, 108 deletions

diff --git a/.ci/scripts/calculate_jobs.py b/.ci/scripts/calculate_jobs.py
index b41ec0b6e2..c2c18b48e3 100755
--- a/.ci/scripts/calculate_jobs.py
+++ b/.ci/scripts/calculate_jobs.py
@@ -29,11 +29,12 @@ IS_PR = os.environ["GITHUB_REF"].startswith("refs/pull/")
 
 # First calculate the various trial jobs.
 #
-# For each type of test we only run on Py3.7 on PRs
+# For PRs, we only run each type of test with the oldest Python version supported (which
+# is Python 3.8 right now)
 
 trial_sqlite_tests = [
     {
-        "python-version": "3.7",
+        "python-version": "3.8",
         "database": "sqlite",
         "extras": "all",
     }
@@ -46,13 +47,13 @@ if not IS_PR:
             "database": "sqlite",
             "extras": "all",
         }
-        for version in ("3.8", "3.9", "3.10", "3.11")
+        for version in ("3.9", "3.10", "3.11")
     )
 
 
 trial_postgres_tests = [
     {
-        "python-version": "3.7",
+        "python-version": "3.8",
         "database": "postgres",
         "postgres-version": "11",
         "extras": "all",
@@ -71,7 +72,7 @@ if not IS_PR:
 
 trial_no_extra_tests = [
     {
-        "python-version": "3.7",
+        "python-version": "3.8",
         "database": "sqlite",
         "extras": "",
     }
diff --git a/.github/workflows/release-artifacts.yml b/.github/workflows/release-artifacts.yml
index 0981200401..f331f67d97 100644
--- a/.github/workflows/release-artifacts.yml
+++ b/.github/workflows/release-artifacts.yml
@@ -144,7 +144,7 @@ jobs:
 
       - name: Only build a single wheel on PR
         if: startsWith(github.ref, 'refs/pull/')
-        run: echo "CIBW_BUILD="cp37-manylinux_${{ matrix.arch }}"" >> $GITHUB_ENV
+        run: echo "CIBW_BUILD="cp38-manylinux_${{ matrix.arch }}"" >> $GITHUB_ENV
 
       - name: Build wheels
         run: python -m cibuildwheel --output-dir wheelhouse
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 6c22984997..0a01e82984 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -320,7 +320,7 @@ jobs:
 
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.7'
+          python-version: '3.8'
 
       - name: Prepare old deps
         if: steps.cache-poetry-old-deps.outputs.cache-hit != 'true'
@@ -362,7 +362,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["pypy-3.7"]
+        python-version: ["pypy-3.8"]
         extras: ["all"]
 
     steps:
@@ -477,7 +477,7 @@ jobs:
     strategy:
       matrix:
         include:
-          - python-version: "3.7"
+          - python-version: "3.8"
             postgres-version: "11"
 
           - python-version: "3.11"
diff --git a/changelog.d/15851.removal b/changelog.d/15851.removal
new file mode 100644
index 0000000000..e08df4c136
--- /dev/null
+++ b/changelog.d/15851.removal
@@ -0,0 +1 @@
+Remove support for Python 3.7.
diff --git a/docker/Dockerfile-dhvirtualenv b/docker/Dockerfile-dhvirtualenv
index 861129ebc2..b7679924c2 100644
--- a/docker/Dockerfile-dhvirtualenv
+++ b/docker/Dockerfile-dhvirtualenv
@@ -28,12 +28,12 @@ FROM docker.io/library/${distro} as builder
 
 RUN apt-get update -qq -o Acquire::Languages=none
 RUN env DEBIAN_FRONTEND=noninteractive apt-get install \
-        -yqq --no-install-recommends \
-        build-essential \
-        ca-certificates \
-        devscripts \
-        equivs \
-        wget
+    -yqq --no-install-recommends \
+    build-essential \
+    ca-certificates \
+    devscripts \
+    equivs \
+    wget
 
 # fetch and unpack the package
 # We are temporarily using a fork of dh-virtualenv due to an incompatibility with Python 3.11, which ships with
@@ -62,33 +62,29 @@ FROM docker.io/library/${distro}
 ARG distro=""
 ENV distro ${distro}
 
-# Python < 3.7 assumes LANG="C" means ASCII-only and throws on printing unicode
-# http://bugs.python.org/issue19846
-ENV LANG C.UTF-8
-
 # Install the build dependencies
 #
 # NB: keep this list in sync with the list of build-deps in debian/control
 # TODO: it would be nice to do that automatically.
 RUN apt-get update -qq -o Acquire::Languages=none \
     && env DEBIAN_FRONTEND=noninteractive apt-get install \
-        -yqq --no-install-recommends -o Dpkg::Options::=--force-unsafe-io \
-        build-essential \
-        curl \
-        debhelper \
-        devscripts \
-        libsystemd-dev \
-        lsb-release \
-        pkg-config \
-        python3-dev \
-        python3-pip \
-        python3-setuptools \
-        python3-venv \
-        sqlite3 \
-        libpq-dev \
-        libicu-dev \
-        pkg-config \
-        xmlsec1
+    -yqq --no-install-recommends -o Dpkg::Options::=--force-unsafe-io \
+    build-essential \
+    curl \
+    debhelper \
+    devscripts \
+    libsystemd-dev \
+    lsb-release \
+    pkg-config \
+    python3-dev \
+    python3-pip \
+    python3-setuptools \
+    python3-venv \
+    sqlite3 \
+    libpq-dev \
+    libicu-dev \
+    pkg-config \
+    xmlsec1
 
 # Install rust and ensure it's in the PATH
 ENV RUSTUP_HOME=/rust
diff --git a/docs/setup/installation.md b/docs/setup/installation.md
index 86e506a3e2..4ca8c6b697 100644
--- a/docs/setup/installation.md
+++ b/docs/setup/installation.md
@@ -200,7 +200,7 @@ When following this route please make sure that the [Platform-specific prerequis
 System requirements:
 
 - POSIX-compliant system (tested on Linux & OS X)
-- Python 3.7 or later, up to Python 3.11.
+- Python 3.8 or later, up to Python 3.11.
 - At least 1GB of free RAM if you want to join large public rooms like #matrix:matrix.org
 
 If building on an uncommon architecture for which pre-built wheels are
diff --git a/docs/upgrade.md b/docs/upgrade.md
index 4cd38b1393..384f4010b4 100644
--- a/docs/upgrade.md
+++ b/docs/upgrade.md
@@ -87,6 +87,18 @@ process, for example:
     wget https://packages.matrix.org/debian/pool/main/m/matrix-synapse-py3/matrix-synapse-py3_1.3.0+stretch1_amd64.deb
     dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
     ```
+
+# Upgrading to v1.88.0
+
+## Minimum supported Python version
+
+The minimum supported Python version has been increased from v3.7 to v3.8.
+You will need Python 3.8 to run Synapse v1.88.0 (due out July 18th, 2023).
+
+If you use current versions of the Matrix.org-distributed Debian
+packages or Docker images, no action is required.
+
+
 # Upgrading to v1.86.0
 
 ## Minimum supported Rust version
diff --git a/poetry.lock b/poetry.lock
index 9aaf5c7de7..c62337053e 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -41,9 +41,6 @@ files = [
     {file = "attrs-23.1.0.tar.gz", hash = "sha256:6279836d581513a26f1bf235f9acd333bc9115683f14f7e8fae46c98fc50e015"},
 ]
 
-[package.dependencies]
-importlib-metadata = {version = "*", markers = "python_version < \"3.8\""}
-
 [package.extras]
 cov = ["attrs[tests]", "coverage[toml] (>=5.3)"]
 dev = ["attrs[docs,tests]", "pre-commit"]
@@ -190,7 +187,6 @@ packaging = ">=22.0"
 pathspec = ">=0.9.0"
 platformdirs = ">=2"
 tomli = {version = ">=1.1.0", markers = "python_version < \"3.11\""}
-typed-ast = {version = ">=1.4.2", markers = "python_version < \"3.8\" and implementation_name == \"cpython\""}
 typing-extensions = {version = ">=3.10.0.0", markers = "python_version < \"3.10\""}
 
 [package.extras]
@@ -412,7 +408,6 @@ files = [
 
 [package.dependencies]
 colorama = {version = "*", markers = "platform_system == \"Windows\""}
-importlib-metadata = {version = "*", markers = "python_version < \"3.8\""}
 
 [[package]]
 name = "click-default-group"
@@ -601,7 +596,6 @@ files = [
 
 [package.dependencies]
 gitdb = ">=4.0.1,<5"
-typing-extensions = {version = ">=3.7.4.3", markers = "python_version < \"3.8\""}
 
 [[package]]
 name = "hiredis"
@@ -847,7 +841,6 @@ files = [
 ]
 
 [package.dependencies]
-typing-extensions = {version = ">=3.6.4", markers = "python_version < \"3.8\""}
 zipp = ">=0.5"
 
 [package.extras]
@@ -987,11 +980,9 @@ files = [
 
 [package.dependencies]
 attrs = ">=17.4.0"
-importlib-metadata = {version = "*", markers = "python_version < \"3.8\""}
 importlib-resources = {version = ">=1.4.0", markers = "python_version < \"3.9\""}
 pkgutil-resolve-name = {version = ">=1.3.10", markers = "python_version < \"3.9\""}
 pyrsistent = ">=0.14.0,<0.17.0 || >0.17.0,<0.17.1 || >0.17.1,<0.17.2 || >0.17.2"
-typing-extensions = {version = "*", markers = "python_version < \"3.8\""}
 
 [package.extras]
 format = ["fqdn", "idna", "isoduration", "jsonpointer (>1.13)", "rfc3339-validator", "rfc3987", "uri-template", "webcolors (>=1.11)"]
@@ -1199,7 +1190,6 @@ files = [
 
 [package.dependencies]
 mdurl = ">=0.1,<1.0"
-typing_extensions = {version = ">=3.7.4", markers = "python_version < \"3.8\""}
 
 [package.extras]
 benchmarking = ["psutil", "pytest", "pytest-benchmark"]
@@ -1283,7 +1273,6 @@ files = [
 
 [package.dependencies]
 attrs = "*"
-importlib-metadata = {version = ">=1.4", markers = "python_version < \"3.8\""}
 
 [package.extras]
 dev = ["aiounittest", "black (==22.3.0)", "build (==0.8.0)", "flake8 (==4.0.1)", "isort (==5.9.3)", "mypy (==0.910)", "tox", "twine (==4.0.1)", "twisted"]
@@ -1459,7 +1448,6 @@ files = [
 [package.dependencies]
 mypy-extensions = ">=0.4.3"
 tomli = {version = ">=1.1.0", markers = "python_version < \"3.11\""}
-typed-ast = {version = ">=1.4.0,<2", markers = "python_version < \"3.8\""}
 typing-extensions = ">=3.10"
 
 [package.extras]
@@ -1721,9 +1709,6 @@ files = [
     {file = "platformdirs-3.1.1.tar.gz", hash = "sha256:024996549ee88ec1a9aa99ff7f8fc819bb59e2c3477b410d90a16d32d6e707aa"},
 ]
 
-[package.dependencies]
-typing-extensions = {version = ">=4.4", markers = "python_version < \"3.8\""}
-
 [package.extras]
 docs = ["furo (>=2022.12.7)", "proselint (>=0.13)", "sphinx (>=6.1.3)", "sphinx-autodoc-typehints (>=1.22,!=1.23.4)"]
 test = ["appdirs (==1.4.4)", "covdefaults (>=2.2.2)", "pytest (>=7.2.1)", "pytest-cov (>=4)", "pytest-mock (>=3.10)"]
@@ -2060,7 +2045,6 @@ files = [
 [package.dependencies]
 cryptography = ">=3.1"
 defusedxml = "*"
-importlib-metadata = {version = ">=1.7.0", markers = "python_version < \"3.8\""}
 importlib-resources = {version = "*", markers = "python_version < \"3.9\""}
 pyopenssl = "*"
 python-dateutil = "*"
@@ -2410,9 +2394,7 @@ files = [
 
 [package.dependencies]
 canonicaljson = ">=1.0.0"
-importlib-metadata = {version = "*", markers = "python_version < \"3.8\""}
 pynacl = ">=0.3.0"
-typing-extensions = {version = ">=3.5", markers = "python_version < \"3.8\""}
 unpaddedbase64 = ">=1.0.1"
 
 [package.extras]
@@ -2853,39 +2835,6 @@ six = "*"
 twisted = "*"
 
 [[package]]
-name = "typed-ast"
-version = "1.5.4"
-description = "a fork of Python 2 and 3 ast modules with type comment support"
-optional = false
-python-versions = ">=3.6"
-files = [
-    {file = "typed_ast-1.5.4-cp310-cp310-macosx_10_9_x86_64.whl", hash = "sha256:669dd0c4167f6f2cd9f57041e03c3c2ebf9063d0757dc89f79ba1daa2bfca9d4"},
-    {file = "typed_ast-1.5.4-cp310-cp310-macosx_11_0_arm64.whl", hash = "sha256:211260621ab1cd7324e0798d6be953d00b74e0428382991adfddb352252f1d62"},
-    {file = "typed_ast-1.5.4-cp310-cp310-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:267e3f78697a6c00c689c03db4876dd1efdfea2f251a5ad6555e82a26847b4ac"},
-    {file = "typed_ast-1.5.4-cp310-cp310-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:c542eeda69212fa10a7ada75e668876fdec5f856cd3d06829e6aa64ad17c8dfe"},
-    {file = "typed_ast-1.5.4-cp310-cp310-win_amd64.whl", hash = "sha256:a9916d2bb8865f973824fb47436fa45e1ebf2efd920f2b9f99342cb7fab93f72"},
-    {file = "typed_ast-1.5.4-cp36-cp36m-macosx_10_9_x86_64.whl", hash = "sha256:79b1e0869db7c830ba6a981d58711c88b6677506e648496b1f64ac7d15633aec"},
-    {file = "typed_ast-1.5.4-cp36-cp36m-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:a94d55d142c9265f4ea46fab70977a1944ecae359ae867397757d836ea5a3f47"},
-    {file = "typed_ast-1.5.4-cp36-cp36m-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:183afdf0ec5b1b211724dfef3d2cad2d767cbefac291f24d69b00546c1837fb6"},
-    {file = "typed_ast-1.5.4-cp36-cp36m-win_amd64.whl", hash = "sha256:639c5f0b21776605dd6c9dbe592d5228f021404dafd377e2b7ac046b0349b1a1"},
-    {file = "typed_ast-1.5.4-cp37-cp37m-macosx_10_9_x86_64.whl", hash = "sha256:cf4afcfac006ece570e32d6fa90ab74a17245b83dfd6655a6f68568098345ff6"},
-    {file = "typed_ast-1.5.4-cp37-cp37m-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:ed855bbe3eb3715fca349c80174cfcfd699c2f9de574d40527b8429acae23a66"},
-    {file = "typed_ast-1.5.4-cp37-cp37m-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:6778e1b2f81dfc7bc58e4b259363b83d2e509a65198e85d5700dfae4c6c8ff1c"},
-    {file = "typed_ast-1.5.4-cp37-cp37m-win_amd64.whl", hash = "sha256:0261195c2062caf107831e92a76764c81227dae162c4f75192c0d489faf751a2"},
-    {file = "typed_ast-1.5.4-cp38-cp38-macosx_10_9_x86_64.whl", hash = "sha256:2efae9db7a8c05ad5547d522e7dbe62c83d838d3906a3716d1478b6c1d61388d"},
-    {file = "typed_ast-1.5.4-cp38-cp38-macosx_11_0_arm64.whl", hash = "sha256:7d5d014b7daa8b0bf2eaef684295acae12b036d79f54178b92a2b6a56f92278f"},
-    {file = "typed_ast-1.5.4-cp38-cp38-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:370788a63915e82fd6f212865a596a0fefcbb7d408bbbb13dea723d971ed8bdc"},
-    {file = "typed_ast-1.5.4-cp38-cp38-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:4e964b4ff86550a7a7d56345c7864b18f403f5bd7380edf44a3c1fb4ee7ac6c6"},
-    {file = "typed_ast-1.5.4-cp38-cp38-win_amd64.whl", hash = "sha256:683407d92dc953c8a7347119596f0b0e6c55eb98ebebd9b23437501b28dcbb8e"},
-    {file = "typed_ast-1.5.4-cp39-cp39-macosx_10_9_x86_64.whl", hash = "sha256:4879da6c9b73443f97e731b617184a596ac1235fe91f98d279a7af36c796da35"},
-    {file = "typed_ast-1.5.4-cp39-cp39-macosx_11_0_arm64.whl", hash = "sha256:3e123d878ba170397916557d31c8f589951e353cc95fb7f24f6bb69adc1a8a97"},
-    {file = "typed_ast-1.5.4-cp39-cp39-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:ebd9d7f80ccf7a82ac5f88c521115cc55d84e35bf8b446fcd7836eb6b98929a3"},
-    {file = "typed_ast-1.5.4-cp39-cp39-manylinux_2_5_x86_64.manylinux1_x86_64.manylinux_2_12_x86_64.manylinux2010_x86_64.whl", hash = "sha256:98f80dee3c03455e92796b58b98ff6ca0b2a6f652120c263efdba4d6c5e58f72"},
-    {file = "typed_ast-1.5.4-cp39-cp39-win_amd64.whl", hash = "sha256:0fdbcf2fef0ca421a3f5912555804296f0b0960f0418c440f5d6d3abb549f3e1"},
-    {file = "typed_ast-1.5.4.tar.gz", hash = "sha256:39e21ceb7388e4bb37f4c679d72707ed46c2fbf2a5609b8b8ebc4b067d977df2"},
-]
-
-[[package]]
 name = "types-bleach"
 version = "6.0.0.3"
 description = "Typing stubs for bleach"
@@ -3293,5 +3242,5 @@ user-search = ["pyicu"]
 
 [metadata]
 lock-version = "2.0"
-python-versions = "^3.7.1"
-content-hash = "7f31754a1009d7b6c9a1bd7221a0b243ffd510f362c28f0da417aaac16757a87"
+python-versions = "^3.8.0"
+content-hash = "0832381cc9e7065e8d95c810d732aa031b98d55cf188719989b12d841993e62e"
diff --git a/pyproject.toml b/pyproject.toml
index 192a07756b..a6e3a935a9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -147,7 +147,7 @@ synapse_review_recent_signups = "synapse._scripts.review_recent_signups:main"
 update_synapse_database = "synapse._scripts.update_synapse_database:main"
 
 [tool.poetry.dependencies]
-python = "^3.7.1"
+python = "^3.8.0"
 
 # Mandatory Dependencies
 # ----------------------
@@ -203,9 +203,6 @@ ijson = ">=3.1.4"
 matrix-common = "^1.3.0"
 # We need packaging.requirements.Requirement, added in 16.1.
 packaging = ">=16.1"
-# At the time of writing, we only use functions from the version `importlib.metadata`
-# which shipped in Python 3.8. This corresponds to version 1.4 of the backport.
-importlib_metadata = { version = ">=1.4", python = "<3.8" }
 # This is the most recent version of Pydantic with available on common distros.
 # We are currently incompatible with >=2.0.0: (https://github.com/matrix-org/synapse/issues/15858)
 pydantic = "^1.7.4"
diff --git a/synapse/__init__.py b/synapse/__init__.py
index b97ee59f15..6c1801862b 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -25,8 +25,8 @@ from synapse.util.rust import check_rust_lib_up_to_date
 from synapse.util.stringutils import strtobool
 
 # Check that we're not running on an unsupported Python version.
-if sys.version_info < (3, 7):
-    print("Synapse requires Python 3.7 or above.")
+if sys.version_info < (3, 8):
+    print("Synapse requires Python 3.8 or above.")
     sys.exit(1)
 
 # Allow using the asyncio reactor via env var.
diff --git a/synapse/util/check_dependencies.py b/synapse/util/check_dependencies.py
index 1c0fde4966..114130a08f 100644
--- a/synapse/util/check_dependencies.py
+++ b/synapse/util/check_dependencies.py
@@ -21,16 +21,13 @@ require. But this is probably just symptomatic of Python's package management.
 """
 
 import logging
+from importlib import metadata
 from typing import Iterable, NamedTuple, Optional
 
 from packaging.requirements import Requirement
 
 DISTRIBUTION_NAME = "matrix-synapse"
 
-try:
-    from importlib import metadata
-except ImportError:
-    import importlib_metadata as metadata  # type: ignore[no-redef]
 
 __all__ = ["check_requirements"]
 
diff --git a/tests/metrics/test_metrics.py b/tests/metrics/test_metrics.py
index 7c3656d049..d14876826c 100644
--- a/tests/metrics/test_metrics.py
+++ b/tests/metrics/test_metrics.py
@@ -12,19 +12,13 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from importlib import metadata
 from typing import Dict, Tuple
-
-from typing_extensions import Protocol
-
-try:
-    from importlib import metadata
-except ImportError:
-    import importlib_metadata as metadata  # type: ignore[no-redef]
-
 from unittest.mock import patch
 
 from pkg_resources import parse_version
 from prometheus_client.core import Sample
+from typing_extensions import Protocol
 
 from synapse.app._base import _set_prometheus_client_use_created_metrics
 from synapse.metrics import REGISTRY, InFlightGauge, generate_latest