Merge remote-tracking branch 'origin/master' into 3860-http-more-immutables

.circleci/Dockerfile.debian

@@ -1,7 +1,7 @@
 ARG TAG
 FROM debian:${TAG}
 ARG PYTHON_VERSION
-
+ENV DEBIAN_FRONTEND noninteractive
 ENV WHEELHOUSE_PATH /tmp/wheelhouse
 ENV VIRTUALENV_PATH /tmp/venv
 # This will get updated by the CircleCI checkout step.

.circleci/Dockerfile.oraclelinux

@@ -1,5 +1,5 @@
 ARG TAG
-FROM centos:${TAG}
+FROM oraclelinux:${TAG}
 ARG PYTHON_VERSION
 
 ENV WHEELHOUSE_PATH /tmp/wheelhouse
@@ -13,7 +13,6 @@ RUN yum install --assumeyes \
     sudo \
     make automake gcc gcc-c++ \
     python${PYTHON_VERSION} \
-    python${PYTHON_VERSION}-devel \
     libffi-devel \
     openssl-devel \
     libyaml \

.circleci/Dockerfile.ubuntu

@@ -1,7 +1,7 @@
 ARG TAG
 FROM ubuntu:${TAG}
 ARG PYTHON_VERSION
-
+ENV DEBIAN_FRONTEND noninteractive
 ENV WHEELHOUSE_PATH /tmp/wheelhouse
 ENV VIRTUALENV_PATH /tmp/venv
 # This will get updated by the CircleCI checkout step.

.circleci/config.yml

@@ -15,28 +15,20 @@ workflows:
   ci:
     jobs:
       # Start with jobs testing various platforms.
-      - "debian-9":
-          {}
       - "debian-10":
+          {}
+      - "debian-11":
           requires:
-            - "debian-9"
+            - "debian-10"
 
       - "ubuntu-20-04":
           {}
       - "ubuntu-18-04":
           requires:
             - "ubuntu-20-04"
-      - "ubuntu-16-04":
-          requires:
-            - "ubuntu-20-04"
 
-      - "fedora-29":
+      # Equivalent to RHEL 8; CentOS 8 is dead.
-          {}
+      - "oraclelinux-8":
-      - "fedora-28":
-          requires:
-            - "fedora-29"
-
-      - "centos-8":
           {}
 
       - "nixos":
@@ -47,18 +39,12 @@ workflows:
           name: "NixOS 21.11"
           nixpkgs: "21.11"
 
-      # Test against PyPy 2.7
+      # Eventually, test against PyPy 3.8
-      - "pypy27-buster":
+      #- "pypy27-buster":
-          {}
+      #    {}
-
-      # Test against Python 3:
-      - "python37":
-          {}
 
       # Other assorted tasks and configurations
-      - "lint":
+      - "codechecks":
-          {}
-      - "codechecks3":
           {}
       - "pyinstaller":
           {}
@@ -74,7 +60,7 @@ workflows:
           requires:
             # If the unit test suite doesn't pass, don't bother running the
             # integration tests.
-            - "debian-9"
+            - "debian-10"
 
       - "typechecks":
           {}
@@ -104,24 +90,19 @@ workflows:
       #  https://app.circleci.com/settings/organization/github/tahoe-lafs/contexts
       - "build-image-debian-10": &DOCKERHUB_CONTEXT
           context: "dockerhub-auth"
-      - "build-image-debian-9":
+      - "build-image-debian-11":
-          <<: *DOCKERHUB_CONTEXT
-      - "build-image-ubuntu-16-04":
           <<: *DOCKERHUB_CONTEXT
       - "build-image-ubuntu-18-04":
           <<: *DOCKERHUB_CONTEXT
       - "build-image-ubuntu-20-04":
           <<: *DOCKERHUB_CONTEXT
-      - "build-image-fedora-28":
+      - "build-image-fedora-35":
           <<: *DOCKERHUB_CONTEXT
-      - "build-image-fedora-29":
+      - "build-image-oraclelinux-8":
-          <<: *DOCKERHUB_CONTEXT
-      - "build-image-centos-8":
-          <<: *DOCKERHUB_CONTEXT
-      - "build-image-pypy27-buster":
-          <<: *DOCKERHUB_CONTEXT
-      - "build-image-python37-ubuntu":
           <<: *DOCKERHUB_CONTEXT
+      # Restore later as PyPy38
+      #- "build-image-pypy27-buster":
+      #    <<: *DOCKERHUB_CONTEXT
 
 
 jobs:
@@ -147,10 +128,10 @@ jobs:
             # Since this job is never scheduled this step is never run so the
             # actual value here is irrelevant.
 
-  lint:
+  codechecks:
     docker:
       - <<: *DOCKERHUB_AUTH
-        image: "circleci/python:2"
+        image: "cimg/python:3.9"
 
     steps:
       - "checkout"
@@ -165,28 +146,10 @@ jobs:
           command: |
             ~/.local/bin/tox -e codechecks
 
-  codechecks3:
-    docker:
-      - <<: *DOCKERHUB_AUTH
-        image: "circleci/python:3"
-
-    steps:
-      - "checkout"
-
-      - run:
-          name: "Install tox"
-          command: |
-            pip install --user tox
-
-      - run:
-          name: "Static-ish code checks"
-          command: |
-            ~/.local/bin/tox -e codechecks3
-
   pyinstaller:
     docker:
       - <<: *DOCKERHUB_AUTH
-        image: "circleci/python:2"
+        image: "cimg/python:3.9"
 
     steps:
       - "checkout"
@@ -209,10 +172,10 @@ jobs:
           command: |
             dist/Tahoe-LAFS/tahoe --version
 
-  debian-9: &DEBIAN
+  debian-10: &DEBIAN
     docker:
       - <<: *DOCKERHUB_AUTH
-        image: "tahoelafsci/debian:9-py2.7"
+        image: "tahoelafsci/debian:10-py3.7"
         user: "nobody"
 
     environment: &UTF_8_ENVIRONMENT
@@ -226,7 +189,7 @@ jobs:
       # filenames and argv).
       LANG: "en_US.UTF-8"
       # Select a tox environment to run for this job.
-      TAHOE_LAFS_TOX_ENVIRONMENT: "py27"
+      TAHOE_LAFS_TOX_ENVIRONMENT: "py37"
       # Additional arguments to pass to tox.
       TAHOE_LAFS_TOX_ARGS: ""
       # The path in which test artifacts will be placed.
@@ -294,29 +257,29 @@ jobs:
               /tmp/venv/bin/codecov
             fi
 
-
+  debian-11:
-  debian-10:
     <<: *DEBIAN
     docker:
       - <<: *DOCKERHUB_AUTH
-        image: "tahoelafsci/debian:10-py2.7"
+        image: "tahoelafsci/debian:11-py3.9"
         user: "nobody"
-
-
-  pypy27-buster:
-    <<: *DEBIAN
-    docker:
-      - <<: *DOCKERHUB_AUTH
-        image: "tahoelafsci/pypy:buster-py2"
-        user: "nobody"
-
     environment:
       <<: *UTF_8_ENVIRONMENT
-      # We don't do coverage since it makes PyPy far too slow:
+      TAHOE_LAFS_TOX_ENVIRONMENT: "py39"
-      TAHOE_LAFS_TOX_ENVIRONMENT: "pypy27"
-      # Since we didn't collect it, don't upload it.
-      UPLOAD_COVERAGE: ""
 
+  # Restore later using PyPy3.8
+  # pypy27-buster:
+  #   <<: *DEBIAN
+  #   docker:
+  #     - <<: *DOCKERHUB_AUTH
+  #       image: "tahoelafsci/pypy:buster-py2"
+  #       user: "nobody"
+  #   environment:
+  #     <<: *UTF_8_ENVIRONMENT
+  #     # We don't do coverage since it makes PyPy far too slow:
+  #     TAHOE_LAFS_TOX_ENVIRONMENT: "pypy27"
+  #     # Since we didn't collect it, don't upload it.
+  #     UPLOAD_COVERAGE: ""
 
   c-locale:
     <<: *DEBIAN
@@ -364,25 +327,8 @@ jobs:
       - run: *SETUP_VIRTUALENV
       - run: *RUN_TESTS
 
-
-  ubuntu-16-04:
-    <<: *DEBIAN
-    docker:
-      - <<: *DOCKERHUB_AUTH
-        image: "tahoelafsci/ubuntu:16.04-py2.7"
-        user: "nobody"
-
-
   ubuntu-18-04: &UBUNTU_18_04
     <<: *DEBIAN
-    docker:
-      - <<: *DOCKERHUB_AUTH
-        image: "tahoelafsci/ubuntu:18.04-py2.7"
-        user: "nobody"
-
-
-  python37:
-    <<: *UBUNTU_18_04
     docker:
       - <<: *DOCKERHUB_AUTH
         image: "tahoelafsci/ubuntu:18.04-py3.7"
@@ -401,17 +347,21 @@ jobs:
     <<: *DEBIAN
     docker:
       - <<: *DOCKERHUB_AUTH
-        image: "tahoelafsci/ubuntu:20.04"
+        image: "tahoelafsci/ubuntu:20.04-py3.9"
         user: "nobody"
+    environment:
+      <<: *UTF_8_ENVIRONMENT
+      TAHOE_LAFS_TOX_ENVIRONMENT: "py39"
 
-
+  oraclelinux-8: &RHEL_DERIV
-  centos-8: &RHEL_DERIV
     docker:
       - <<: *DOCKERHUB_AUTH
-        image: "tahoelafsci/centos:8-py2"
+        image: "tahoelafsci/oraclelinux:8-py3.8"
         user: "nobody"
 
-    environment: *UTF_8_ENVIRONMENT
+    environment:
+      <<: *UTF_8_ENVIRONMENT
+      TAHOE_LAFS_TOX_ENVIRONMENT: "py38"
 
     # pip cannot install packages if the working directory is not readable.
     # We want to run a lot of steps as nobody instead of as root.
@@ -427,20 +377,11 @@ jobs:
       - store_artifacts: *STORE_OTHER_ARTIFACTS
       - run: *SUBMIT_COVERAGE
 
-
+  fedora-35:
-  fedora-28:
     <<: *RHEL_DERIV
     docker:
       - <<: *DOCKERHUB_AUTH
-        image: "tahoelafsci/fedora:28-py"
+        image: "tahoelafsci/fedora:35-py3"
-        user: "nobody"
-
-
-  fedora-29:
-    <<: *RHEL_DERIV
-    docker:
-      - <<: *DOCKERHUB_AUTH
-        image: "tahoelafsci/fedora:29-py"
         user: "nobody"
 
   nixos:
@@ -554,7 +495,7 @@ jobs:
   typechecks:
     docker:
       - <<: *DOCKERHUB_AUTH
-        image: "tahoelafsci/ubuntu:18.04-py3"
+        image: "tahoelafsci/ubuntu:18.04-py3.7"
 
     steps:
       - "checkout"
@@ -566,7 +507,7 @@ jobs:
   docs:
     docker:
       - <<: *DOCKERHUB_AUTH
-        image: "tahoelafsci/ubuntu:18.04-py3"
+        image: "tahoelafsci/ubuntu:18.04-py3.7"
 
     steps:
       - "checkout"
@@ -589,13 +530,14 @@ jobs:
         image: "cimg/base:2022.01"
 
     environment:
-      DISTRO: "tahoelafsci/<DISTRO>:foo-py2"
+      DISTRO: "tahoelafsci/<DISTRO>:foo-py3.9"
-      TAG: "tahoelafsci/distro:<TAG>-py2"
+      TAG: "tahoelafsci/distro:<TAG>-py3.9"
       PYTHON_VERSION: "tahoelafsci/distro:tag-py<PYTHON_VERSION}"
 
     steps:
       - "checkout"
-      - "setup_remote_docker"
+      - setup_remote_docker:
+          version: "20.10.11"
       - run:
           name: "Log in to Dockerhub"
           command: |
@@ -622,39 +564,20 @@ jobs:
     environment:
       DISTRO: "debian"
       TAG: "10"
-      PYTHON_VERSION: "2.7"
+      PYTHON_VERSION: "3.7"
 
 
-  build-image-debian-9:
+  build-image-debian-11:
     <<: *BUILD_IMAGE
 
     environment:
       DISTRO: "debian"
-      TAG: "9"
+      TAG: "11"
-      PYTHON_VERSION: "2.7"
+      PYTHON_VERSION: "3.9"
-
-
-  build-image-ubuntu-16-04:
-    <<: *BUILD_IMAGE
-
-    environment:
-      DISTRO: "ubuntu"
-      TAG: "16.04"
-      PYTHON_VERSION: "2.7"
-
 
   build-image-ubuntu-18-04:
     <<: *BUILD_IMAGE
 
-    environment:
-      DISTRO: "ubuntu"
-      TAG: "18.04"
-      PYTHON_VERSION: "2.7"
-
-
-  build-image-python37-ubuntu:
-    <<: *BUILD_IMAGE
-
     environment:
       DISTRO: "ubuntu"
       TAG: "18.04"
@@ -667,43 +590,32 @@ jobs:
     environment:
       DISTRO: "ubuntu"
       TAG: "20.04"
-      PYTHON_VERSION: "2.7"
+      PYTHON_VERSION: "3.9"
 
 
-  build-image-centos-8:
+  build-image-oraclelinux-8:
     <<: *BUILD_IMAGE
 
     environment:
-      DISTRO: "centos"
+      DISTRO: "oraclelinux"
       TAG: "8"
-      PYTHON_VERSION: "2"
+      PYTHON_VERSION: "3.8"
 
-
+  build-image-fedora-35:
-  build-image-fedora-28:
     <<: *BUILD_IMAGE
 
     environment:
       DISTRO: "fedora"
-      TAG: "28"
+      TAG: "35"
-      # The default on Fedora (this version anyway) is still Python 2.
+      PYTHON_VERSION: "3"
-      PYTHON_VERSION: ""
 
+  # build-image-pypy27-buster:
+  #   <<: *BUILD_IMAGE
 
-  build-image-fedora-29:
+  #   environment:
-    <<: *BUILD_IMAGE
+  #     DISTRO: "pypy"
-
+  #     TAG: "buster"
-    environment:
+  #     # We only have Python 2 for PyPy right now so there's no support for
-      DISTRO: "fedora"
+  #     # setting up PyPy 3 in the image building toolchain.  This value is just
-      TAG: "29"
+  #     # for constructing the right Docker image tag.
-
+  #     PYTHON_VERSION: "2"
-
-  build-image-pypy27-buster:
-    <<: *BUILD_IMAGE
-
-    environment:
-      DISTRO: "pypy"
-      TAG: "buster"
-      # We only have Python 2 for PyPy right now so there's no support for
-      # setting up PyPy 3 in the image building toolchain.  This value is just
-      # for constructing the right Docker image tag.
-      PYTHON_VERSION: "2"

.github/workflows/ci.yml

@@ -38,14 +38,11 @@ jobs:
           - windows-latest
           - ubuntu-latest
         python-version:
-          - 2.7
           - 3.7
           - 3.8
           - 3.9
         include:
           # On macOS don't bother with 3.7-3.8, just to get faster builds.
-          - os: macos-10.15
-            python-version: 2.7
           - os: macos-latest
             python-version: 3.9
 
@@ -108,25 +105,6 @@ jobs:
       # Action for this, as of Jan 2021 it does not support Python coverage
       # files - only lcov files.  Therefore, we use coveralls-python, the
       # coveralls.io-supplied Python reporter, for this.
-      #
-      # It is coveralls-python 1.x that has maintained compatibility
-      # with Python 2, while coveralls-python 3.x is compatible with
-      # Python 3.  Sadly we can't use them both in the same workflow.
-      #
-      # The two versions of coveralls-python are somewhat mutually
-      # incompatible.  Mixing these two different versions when
-      # reporting coverage to coveralls.io will lead to grief, since
-      # they get job IDs in different fashion.  If we use both
-      # versions of coveralls in the same workflow, the finalizing
-      # step will be able to mark only part of the jobs as done, and
-      # the other part will be left hanging, never marked as done: it
-      # does not matter if we make an API call or `coveralls --finish`
-      # to indicate that CI has finished running.
-      #
-      # So we try to use the newer coveralls-python that is available
-      # via Python 3 (which is present in GitHub Actions tool cache,
-      # even when we're running Python 2.7 tests) throughout this
-      # workflow.
       - name: "Report Coverage to Coveralls"
         run: |
           pip3 install --upgrade coveralls==3.0.1
@@ -179,13 +157,10 @@ jobs:
           - windows-latest
           - ubuntu-latest
         python-version:
-          - 2.7
           - 3.7
           - 3.9
         include:
           # On macOS don't bother with 3.7, just to get faster builds.
-          - os: macos-10.15
-            python-version: 2.7
           - os: macos-latest
             python-version: 3.9
 
@@ -201,9 +176,7 @@ jobs:
       - name: Install Tor [macOS, ${{ matrix.python-version }} ]
         if: ${{ contains(matrix.os, 'macos') }}
         run: |
-          brew extract --version 0.4.5.8 tor homebrew/cask
+          brew install tor
-          brew install tor@0.4.5.8
-          brew link --overwrite tor@0.4.5.8
 
       - name: Install Tor [Windows]
         if: matrix.os == 'windows-latest'
@@ -242,13 +215,13 @@ jobs:
       - name: Display tool versions
         run: python misc/build_helpers/show-tool-versions.py
 
-      - name: Run "Python 2 integration tests"
-        if: ${{ matrix.python-version == '2.7' }}
-        run: tox -e integration
-
       - name: Run "Python 3 integration tests"
-        if: ${{ matrix.python-version != '2.7' }}
+        env:
-        run: tox -e integration3
+          # On macOS this is necessary to ensure unix socket paths for tor
+          # aren't too long. On Windows tox won't pass it through so it has no
+          # effect. On Linux it doesn't make a difference one way or another.
+          TMPDIR: "/tmp"
+        run: tox -e integration
 
       - name: Upload eliot.log in case of failure
         uses: actions/upload-artifact@v1
@@ -267,7 +240,7 @@ jobs:
           - windows-latest
           - ubuntu-latest
         python-version:
-          - 2.7
+          - 3.9
 
     steps:
 

Makefile

@@ -17,7 +17,7 @@ PYTHON=python
 export PYTHON
 PYFLAKES=flake8
 export PYFLAKES
-VIRTUAL_ENV=./.tox/py27
+VIRTUAL_ENV=./.tox/py37
 SOURCES=src/allmydata static misc setup.py
 APPNAME=tahoe-lafs
 TEST_SUITE=allmydata
@@ -35,7 +35,7 @@ test: .tox/create-venvs.log
 # Run codechecks first since it takes the least time to report issues early.
 	tox --develop -e codechecks
 # Run all the test environments in parallel to reduce run-time
-	tox --develop -p auto -e 'py27,py37,pypy27'
+	tox --develop -p auto -e 'py37'
 .PHONY: test-venv-coverage
 ## Run all tests with coverage collection and reporting.
 test-venv-coverage:
@@ -136,7 +136,7 @@ count-lines:
 # Here is a list of testing tools that can be run with 'python' from a
 # virtualenv in which Tahoe has been installed. There used to be Makefile
 # targets for each, but the exact path to a suitable python is now up to the
-# developer. But as a hint, after running 'tox', ./.tox/py27/bin/python will
+# developer. But as a hint, after running 'tox', ./.tox/py37/bin/python will
 # probably work.
 
 # src/allmydata/test/bench_dirnode.py

README.rst

@@ -53,12 +53,11 @@ For more detailed instructions, read `Installing Tahoe-LAFS <docs/Installation/i
 
 Once ``tahoe --version`` works, see `How to Run Tahoe-LAFS <docs/running.rst>`__ to learn how to set up your first Tahoe-LAFS node.
 
-🐍 Python 3 Support 
+🐍 Python 2
---------------------
+-----------
 
-Python 3 support has been introduced starting with Tahoe-LAFS 1.16.0, alongside Python 2.
+Python 3.7 or later is now required.
-System administrators are advised to start running Tahoe on Python 3 and should expect Python 2 support to be dropped in a future version.
+If you are still using Python 2.7, use Tahoe-LAFS version 1.17.1.
-Please, feel free to file issues if you run into bugs while running Tahoe on Python 3.
 
 
 🤖 Issues

docs/release-checklist.rst

@@ -122,7 +122,7 @@ they will need to evaluate which contributors' signatures they trust.
 
   - these should all pass:
 
-    - tox -e py27,codechecks,docs,integration
+    - tox -e py37,codechecks,docs,integration
 
   - these can fail (ideally they should not of course):
 

integration/conftest.py

@@ -462,10 +462,8 @@ def chutney(reactor, temp_dir):
     )
     pytest_twisted.blockon(proto.done)
 
-    # XXX: Here we reset Chutney to the last revision known to work
+    # XXX: Here we reset Chutney to a specific revision known to work,
-    # with Python 2, as a workaround for Chutney moving to Python 3.
+    # since there are no stability guarantees or releases yet.
-    # When this is no longer necessary, we will have to drop this and
-    # add '--depth=1' back to the above 'git clone' subprocess.
     proto = _DumpOutputProtocol(None)
     reactor.spawnProcess(
         proto,
@@ -473,7 +471,7 @@ def chutney(reactor, temp_dir):
         (
             'git', '-C', chutney_dir,
             'reset', '--hard',
-            '99bd06c7554b9113af8c0877b6eca4ceb95dcbaa'
+            'c825cba0bcd813c644c6ac069deeb7347d3200ee'
         ),
         env=environ,
     )

misc/build_helpers/run-deprecations.py

@@ -26,10 +26,10 @@ python run-deprecations.py [--warnings=STDERRFILE] [--package=PYTHONPACKAGE ] CO
 class RunPP(protocol.ProcessProtocol):
     def outReceived(self, data):
         self.stdout.write(data)
-        sys.stdout.write(data)
+        sys.stdout.write(str(data, sys.stdout.encoding))
     def errReceived(self, data):
         self.stderr.write(data)
-        sys.stderr.write(data)
+        sys.stderr.write(str(data, sys.stdout.encoding))
     def processEnded(self, reason):
         signal = reason.value.signal
         rc = reason.value.exitCode
@@ -100,17 +100,19 @@ def run_command(main):
 
     pp.stdout.seek(0)
     for line in pp.stdout.readlines():
+        line = str(line, sys.stdout.encoding)
         if match(line):
             add(line) # includes newline
 
     pp.stderr.seek(0)
     for line in pp.stderr.readlines():
+        line = str(line, sys.stdout.encoding)
         if match(line):
             add(line)
 
     if warnings:
         if config["warnings"]:
-            with open(config["warnings"], "wb") as f:
+            with open(config["warnings"], "w") as f:
                 print("".join(warnings), file=f)
         print("ERROR: %d deprecation warnings found" % len(warnings))
         sys.exit(1)

newsfragments/3873.incompat

@@ -0,0 +1 @@
+Python 3.7 or later is now required; Python 2 is no longer supported.

pyinstaller.spec

@@ -11,7 +11,10 @@ import struct
 import sys
 
 
-if not hasattr(sys, 'real_prefix'):
+try:
+    import allmydata
+    del allmydata
+except ImportError:
     sys.exit("Please run inside a virtualenv with Tahoe-LAFS installed.")
 
 

setup.py

@@ -55,8 +55,7 @@ install_requires = [
     # * foolscap >= 0.12.6 has an i2p.sam_endpoint() that takes kwargs
     # * foolscap 0.13.2 drops i2p support completely
     # * foolscap >= 21.7 is necessary for Python 3 with i2p support.
-    "foolscap == 0.13.1 ; python_version < '3.0'",
+    "foolscap >= 21.7.0",
-    "foolscap >= 21.7.0 ; python_version > '3.0'",
 
     # * cryptography 2.6 introduced some ed25519 APIs we rely on.  Note that
     #   Twisted[conch] also depends on cryptography and Twisted[tls]
@@ -106,16 +105,10 @@ install_requires = [
     # for 'tahoe invite' and 'tahoe join'
     "magic-wormhole >= 0.10.2",
 
-    # Eliot is contemplating dropping Python 2 support.  Stick to a version we
+    # We want a new enough version to support custom JSON encoders.
-    # know works on Python 2.7.
+    "eliot >= 1.13.0",
-    "eliot ~= 1.7 ; python_version < '3.0'",
-    # On Python 3, we want a new enough version to support custom JSON encoders.
-    "eliot >= 1.13.0 ; python_version > '3.0'",
 
-    # Pyrsistent 0.17.0 (which we use by way of Eliot) has dropped
+    "pyrsistent",
-    # Python 2 entirely; stick to the version known to work for us.
-    "pyrsistent < 0.17.0 ; python_version < '3.0'",
-    "pyrsistent ; python_version > '3.0'",
 
     # A great way to define types of values.
     "attrs >= 18.2.0",
@@ -135,14 +128,8 @@ install_requires = [
     # Linux distribution detection:
     "distro >= 1.4.0",
 
-    # Backported configparser for Python 2:
+    # For the RangeMap datastructure. Need 2.0.2 at least for bugfixes.
-    "configparser ; python_version < '3.0'",
+    "collections-extended >= 2.0.2",
-
-    # For the RangeMap datastructure. Need 2.0.2 at least for bugfixes. Python
-    # 2 doesn't actually need this, since HTTP storage protocol isn't supported
-    # there, so we just pick whatever version so that code imports.
-    "collections-extended >= 2.0.2 ; python_version > '3.0'",
-    "collections-extended ; python_version < '3.0'",
 
     # HTTP server and client
     "klein",
@@ -201,8 +188,7 @@ trove_classifiers=[
     "Natural Language :: English",
     "Programming Language :: C",
     "Programming Language :: Python",
-    "Programming Language :: Python :: 2",
+    "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 2.7",
     "Topic :: Utilities",
     "Topic :: System :: Systems Administration",
     "Topic :: System :: Filesystems",
@@ -229,7 +215,7 @@ def run_command(args, cwd=None):
     use_shell = sys.platform == "win32"
     try:
         p = subprocess.Popen(args, stdout=subprocess.PIPE, cwd=cwd, shell=use_shell)
-    except EnvironmentError as e:  # if this gives a SyntaxError, note that Tahoe-LAFS requires Python 2.7+
+    except EnvironmentError as e:  # if this gives a SyntaxError, note that Tahoe-LAFS requires Python 3.7+
         print("Warning: unable to run %r." % (" ".join(args),))
         print(e)
         return None
@@ -380,8 +366,8 @@ setup(name="tahoe-lafs", # also set in __init__.py
       package_dir = {'':'src'},
       packages=find_packages('src') + ['allmydata.test.plugins'],
       classifiers=trove_classifiers,
-      # We support Python 2.7, and Python 3.7 or later.
+      # We support Python 3.7 or later. 3.10 is not supported quite yet.
-      python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, !=3.5.*, !=3.6.*",
+      python_requires=">=3.7, <3.10",
       install_requires=install_requires,
       extras_require={
           # Duplicate the Twisted pywin32 dependency here.  See
@@ -400,10 +386,6 @@ setup(name="tahoe-lafs", # also set in __init__.py
               "tox",
               "pytest",
               "pytest-twisted",
-              # XXX: decorator isn't a direct dependency, but pytest-twisted
-              # depends on decorator, and decorator 5.x isn't compatible with
-              # Python 2.7.
-              "decorator < 5",
               "hypothesis >= 3.6.1",
               "towncrier",
               "testtools",

tox.ini

@@ -7,8 +7,7 @@
 # the tox-gh-actions package.
 [gh-actions]
 python =
-    2.7: py27-coverage,codechecks
+    3.7: py37-coverage,typechecks,codechecks
-    3.7: py37-coverage,typechecks,codechecks3
     3.8: py38-coverage
     3.9: py39-coverage
     pypy-3.7: pypy3
@@ -17,7 +16,7 @@ python =
 twisted = 1
 
 [tox]
-envlist = typechecks,codechecks,codechecks3,py{27,37,38,39}-{coverage},pypy27,pypy3,integration,integration3
+envlist = typechecks,codechecks,py{37,38,39}-{coverage},pypy27,pypy3,integration
 minversion = 2.4
 
 [testenv]
@@ -35,12 +34,10 @@ deps =
      # happening at the time.  The versions selected here are just the current
      # versions at the time.  Bumping them to keep up with future releases is
      # fine as long as those releases are known to actually work.
-     #
+     pip==22.0.3
-     # For now these are versions that support Python 2.
+     setuptools==60.9.1
-     pip==20.3.4
+     wheel==0.37.1
-     setuptools==44.1.1
+     subunitreporter==22.2.0
-     wheel==0.36.2
-     subunitreporter==19.3.2
      # As an exception, we don't pin certifi because it contains CA
      # certificates which necessarily change over time.  Pinning this is
      # guaranteed to cause things to break eventually as old certificates
@@ -89,40 +86,20 @@ commands =
          coverage: coverage report
 
 [testenv:integration]
-setenv =
-         COVERAGE_PROCESS_START=.coveragerc
-commands =
-         # NOTE: 'run with "py.test --keep-tempdir -s -v integration/" to debug failures'
-         py.test --timeout=1800 --coverage -v {posargs:integration}
-         coverage combine
-         coverage report
-
-
-[testenv:integration3]
 basepython = python3
+platform = mylinux: linux
+           mymacos: darwin
+           mywindows: win32
 setenv =
          COVERAGE_PROCESS_START=.coveragerc
 commands =
-         python --version
          # NOTE: 'run with "py.test --keep-tempdir -s -v integration/" to debug failures'
          py.test --timeout=1800 --coverage -v {posargs:integration}
          coverage combine
          coverage report
 
 
-# Once 2.7 is dropped, this can be removed. It just does flake8 with Python 2
-# since that can give different results than flake8 on Python 3.
 [testenv:codechecks]
-basepython = python2.7
-setenv =
-	 # If no positional arguments are given, try to run the checks on the
-	 # entire codebase, including various pieces of supporting code.
-	 DEFAULT_FILES=src integration static misc setup.py
-commands =
-         flake8 {posargs:{env:DEFAULT_FILES}}
-
-
-[testenv:codechecks3]
 basepython = python3
 deps =
      # Newer versions of PyLint have buggy configuration
@@ -224,16 +201,11 @@ commands =
          sphinx-build -W -b html -d {toxinidir}/docs/_build/doctrees {toxinidir}/docs {toxinidir}/docs/_build/html
 
 [testenv:pyinstaller]
-# We override this to pass --no-use-pep517 because pyinstaller (3.4, at least)
-# is broken when this feature is enabled.
-install_command = python -m pip install --no-use-pep517 {opts} {packages}
 extras =
 deps =
     {[testenv]deps}
     packaging
-    # PyInstaller 4.0 drops Python 2 support.  When we finish porting to
+    pyinstaller
-    # Python 3 we can reconsider this constraint.
-    pyinstaller < 4.0
     pefile ; platform_system == "Windows"
 # Setting PYTHONHASHSEED to a known value assists with reproducible builds.
 # See https://pyinstaller.readthedocs.io/en/stable/advanced-topics.html#creating-a-reproducible-build