From 8eb6ab47653f7e8be52c310332f8f6d9686cd2ae Mon Sep 17 00:00:00 2001
From: Itamar Turner-Trauring <itamar@itamarst.org>
Date: Mon, 24 Jan 2022 10:40:26 -0500
Subject: [PATCH] Switch to Python 3.7 as minimal version.

---
 .circleci/config.yml     | 12 ++++++------
 .github/workflows/ci.yml |  7 +++----
 Makefile                 |  4 ++--
 misc/python3/Makefile    |  4 ++--
 setup.py                 |  5 ++---
 tox.ini                  |  5 ++---
 6 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 2fc8e88e7..d55b80469 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -49,8 +49,8 @@ workflows:
       - "pypy27-buster":
           {}
 
-      # Just one Python 3.6 configuration while the port is in-progress.
-      - "python36":
+      # Test against Python 3:
+      - "python37":
           {}
 
       # Other assorted tasks and configurations
@@ -118,7 +118,7 @@ workflows:
           <<: *DOCKERHUB_CONTEXT
       - "build-image-pypy27-buster":
           <<: *DOCKERHUB_CONTEXT
-      - "build-image-python36-ubuntu":
+      - "build-image-python37-ubuntu":
           <<: *DOCKERHUB_CONTEXT
 
 
@@ -379,7 +379,7 @@ jobs:
         user: "nobody"
 
 
-  python36:
+  python37:
     <<: *UBUNTU_18_04
     docker:
       - <<: *DOCKERHUB_AUTH
@@ -392,7 +392,7 @@ jobs:
       # this reporter on Python 3.  So drop that and just specify the
       # reporter.
       TAHOE_LAFS_TRIAL_ARGS: "--reporter=subunitv2-file"
-      TAHOE_LAFS_TOX_ENVIRONMENT: "py36"
+      TAHOE_LAFS_TOX_ENVIRONMENT: "py37"
 
 
   ubuntu-20-04:
@@ -577,7 +577,7 @@ jobs:
       PYTHON_VERSION: "2.7"
 
 
-  build-image-python36-ubuntu:
+  build-image-python37-ubuntu:
     <<: *BUILD_IMAGE
 
     environment:
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 8209108bf..5ae70a3bb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -39,12 +39,11 @@ jobs:
           - ubuntu-latest
         python-version:
           - 2.7
-          - 3.6
           - 3.7
           - 3.8
           - 3.9
         include:
-          # On macOS don't bother with 3.6-3.8, just to get faster builds.
+          # 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
@@ -181,10 +180,10 @@ jobs:
           - ubuntu-latest
         python-version:
           - 2.7
-          - 3.6
+          - 3.7
           - 3.9
         include:
-          # On macOS don't bother with 3.6, just to get faster builds.
+          # On macOS don't bother with 3.7, just to get faster builds.
           - os: macos-10.15
             python-version: 2.7
           - os: macos-latest
diff --git a/Makefile b/Makefile
index 5d8bf18ba..33a40df02 100644
--- a/Makefile
+++ b/Makefile
@@ -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,py36,pypy27'
+	tox --develop -p auto -e 'py27,py37,pypy27'
 .PHONY: test-venv-coverage
 ## Run all tests with coverage collection and reporting.
 test-venv-coverage:
@@ -51,7 +51,7 @@ test-venv-coverage:
 .PHONY: test-py3-all
 ## Run all tests under Python 3
 test-py3-all: .tox/create-venvs.log
-	tox --develop -e py36 allmydata
+	tox --develop -e py37 allmydata
 
 # This is necessary only if you want to automatically produce a new
 # _version.py file from the current git history (without doing a build).
diff --git a/misc/python3/Makefile b/misc/python3/Makefile
index f0ef8b12a..43cb3e3ce 100644
--- a/misc/python3/Makefile
+++ b/misc/python3/Makefile
@@ -37,8 +37,8 @@ test-py3-all-diff: ../../.tox/make-test-py3-all.diff
 # `$ make .tox/make-test-py3-all.diff`
 $(foreach side,old new,../../.tox/make-test-py3-all-$(side).log):
 	cd "../../"
-	tox --develop --notest -e py36-coverage
-	(make VIRTUAL_ENV=./.tox/py36-coverage TEST_SUITE=allmydata \
+	tox --develop --notest -e py37-coverage
+	(make VIRTUAL_ENV=./.tox/py37-coverage TEST_SUITE=allmydata \
 		test-venv-coverage || true) | \
 		sed -E 's/\([0-9]+\.[0-9]{3} secs\)/(#.### secs)/' | \
 		tee "./misc/python3/$(@)"
diff --git a/setup.py b/setup.py
index 53057b808..9a1c76bd8 100644
--- a/setup.py
+++ b/setup.py
@@ -376,9 +376,8 @@ 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 we're working on support for 3.6 (the
-      # highest version that PyPy currently supports).
-      python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, !=3.5.*",
+      # We support Python 2.7, and Python 3.7 or later.
+      python_requires=">=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*, !=3.5.*, !=3.6.*",
       install_requires=install_requires,
       extras_require={
           # Duplicate the Twisted pywin32 dependency here.  See
diff --git a/tox.ini b/tox.ini
index 38cee1f9f..34d555aa7 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,7 +8,6 @@
 [gh-actions]
 python =
     2.7: py27-coverage,codechecks
-    3.6: py36-coverage
     3.7: py37-coverage,typechecks,codechecks3
     3.8: py38-coverage
     3.9: py39-coverage
@@ -18,7 +17,7 @@ python =
 twisted = 1
 
 [tox]
-envlist = typechecks,codechecks,codechecks3,py{27,36,37,38,39}-{coverage},pypy27,pypy3,integration,integration3
+envlist = typechecks,codechecks,codechecks3,py{27,37,38,39}-{coverage},pypy27,pypy3,integration,integration3
 minversion = 2.4
 
 [testenv]
@@ -51,7 +50,7 @@ deps =
      # suffering we're trying to avoid with the above pins.
      certifi
      # VCS hooks support
-     py36,!coverage: pre-commit
+     py37,!coverage: pre-commit
 
 # We add usedevelop=False because testing against a true installation gives
 # more useful results.