Merge bitcoin/bitcoin#28211: Bump python minimum supported version to 3.9

fa25e8b0a1 doc: Recommend lint image build on every call (MarcoFalke)
faf70c1f33 Bump python minimum version to 3.9 (MarcoFalke)
fa8996b930 ci: Bump i686_multiprocess.sh to latest Ubuntu LTS (MarcoFalke)

Pull request description:

  All supported operating systems ship with python 3.9 (or later), so bumping the minimum should not cause any issues. A bump will allow new code to use new python 3.9 features.

  For reference:
  * https://packages.debian.org/bullseye/python3
  * https://packages.ubuntu.com/focal/python3.9
  * FreeBSD 12/13 also ships with 3.9
  * CentOS-like 8/9 also ships with 3.9 (and 3.11)
  * OpenSuse Leap also ships with 3.9 (and 3.11) https://software.opensuse.org/package/python311-base

  This is for Bitcoin Core 27.0 in 2024 (next year), not the soon upcoming 26.0 next month.

ACKs for top commit:
  Sjors:
    ACK fa25e8b0a1
  jamesob:
    ACK fa25e8b0a1 ([`jamesob/ackr/28211.1.MarcoFalke.bump_python_minimum_supp`](https://github.com/jamesob/bitcoin/tree/ackr/28211.1.MarcoFalke.bump_python_minimum_supp))

Tree-SHA512: 86c9f6ac4b5ba94a62ee6a6062dd48a8295d8611a39cdb5829f4f0dbc77aaa1a51edccc7a99275bf699143ad3a6fe826de426d413e5a465e3b0e82b86d10c32e

.python-version

@@ -1 +1 @@
-3.8.17
+3.9.17

ci/test/00_setup_env_i686_multiprocess.sh

@@ -8,7 +8,7 @@ export LC_ALL=C.UTF-8
 
 export HOST=i686-pc-linux-gnu
 export CONTAINER_NAME=ci_i686_multiprocess
-export CI_IMAGE_NAME_TAG="docker.io/amd64/ubuntu:20.04"
+export CI_IMAGE_NAME_TAG="docker.io/amd64/ubuntu:22.04"
 export PACKAGES="cmake llvm clang g++-multilib"
 export DEP_OPTS="DEBUG=1 MULTIPROCESS=1"
 export GOAL="install"

ci/test/00_setup_env_native_nowallet_libbitcoinkernel.sh

@@ -7,9 +7,9 @@
 export LC_ALL=C.UTF-8
 
 export CONTAINER_NAME=ci_native_nowallet_libbitcoinkernel
-export CI_IMAGE_NAME_TAG="docker.io/ubuntu:20.04"
-# Use minimum supported python3.8 and clang-10, see doc/dependencies.md
-export PACKAGES="python3-zmq clang-10 llvm-10 libc++abi-10-dev libc++-10-dev"
-export DEP_OPTS="NO_WALLET=1 CC=clang-10 CXX='clang++-10 -stdlib=libc++'"
+export CI_IMAGE_NAME_TAG="docker.io/debian:bullseye"
+# Use minimum supported python3.9 and clang-10 (or best-effort clang-11), see doc/dependencies.md
+export PACKAGES="python3-zmq clang-11 llvm-11 libc++abi-11-dev libc++-11-dev"
+export DEP_OPTS="NO_WALLET=1 CC=clang-11 CXX='clang++-11 -stdlib=libc++'"
 export GOAL="install"
 export BITCOIN_CONFIG="--enable-reduce-exports --enable-experimental-util-chainstate --with-experimental-kernel-lib --enable-shared"

ci/test/00_setup_env_native_qt5.sh

@@ -7,8 +7,8 @@
 export LC_ALL=C.UTF-8
 
 export CONTAINER_NAME=ci_native_qt5
-export CI_IMAGE_NAME_TAG="docker.io/ubuntu:20.04"
-# Use minimum supported python3.8 and gcc-9, see doc/dependencies.md
+export CI_IMAGE_NAME_TAG="docker.io/debian:bullseye"
+# Use minimum supported python3.9 and gcc-9, see doc/dependencies.md
 export PACKAGES="gcc-9 g++-9 python3-zmq qtbase5-dev qttools5-dev-tools libdbus-1-dev libharfbuzz-dev"
 export DEP_OPTS="NO_QT=1 NO_UPNP=1 NO_NATPMP=1 DEBUG=1 ALLOW_HOST_PACKAGES=1 CC=gcc-9 CXX=g++-9"
 export TEST_RUNNER_EXTRA="--previous-releases --coverage --extended --exclude feature_dbcrash"  # Run extended tests so that coverage does not fail, but exclude the very slow dbcrash

configure.ac

@@ -128,8 +128,8 @@ AC_PATH_TOOL([AR], [ar])
 AC_PATH_TOOL([GCOV], [gcov])
 AC_PATH_TOOL([LLVM_COV], [llvm-cov])
 AC_PATH_PROG([LCOV], [lcov])
-dnl Python 3.8 is specified in .python-version and should be used if available, see doc/dependencies.md
-AC_PATH_PROGS([PYTHON], [python3.8 python3.9 python3.10 python3.11 python3.12 python3 python])
+dnl The minimum supported version is specified in .python-version and should be used if available, see doc/dependencies.md
+AC_PATH_PROGS([PYTHON], [python3.9 python3.10 python3.11 python3.12 python3 python])
 AC_PATH_PROG([GENHTML], [genhtml])
 AC_PATH_PROG([GIT], [git])
 AC_PATH_PROG([CCACHE], [ccache])

doc/dependencies.md

@@ -10,7 +10,7 @@ You can find installation instructions in the `build-*.md` file for your platfor
 | [Automake](https://www.gnu.org/software/automake/) | [1.13](https://github.com/bitcoin/bitcoin/pull/18290) |
 | [Clang](https://clang.llvm.org) | [10.0](https://github.com/bitcoin/bitcoin/pull/27682) |
 | [GCC](https://gcc.gnu.org) | [9.1](https://github.com/bitcoin/bitcoin/pull/27662) |
-| [Python](https://www.python.org) (scripts, tests) | [3.8](https://github.com/bitcoin/bitcoin/pull/27483) |
+| [Python](https://www.python.org) (scripts, tests) | [3.9](https://github.com/bitcoin/bitcoin/pull/28211) |
 | [systemtap](https://sourceware.org/systemtap/) ([tracing](tracing.md))| N/A |
 
 ## Required

test/functional/test_framework/util.py

@@ -287,10 +287,10 @@ def sha256sum_file(filename):
     return h.digest()
 
 
-# TODO: Remove and use random.randbytes(n) instead, available in Python 3.9
+# TODO: Remove and use random.randbytes(n) directly
 def random_bytes(n):
     """Return a random bytes object of length n."""
-    return bytes(random.getrandbits(8) for i in range(n))
+    return random.randbytes(n)
 
 
 # RPC/P2P connection constants and functions

test/lint/README.md

@@ -7,13 +7,11 @@ To run linters locally with the same versions as the CI environment, use the inc
 Dockerfile:
 
 ```sh
-DOCKER_BUILDKIT=1 docker build -t bitcoin-linter --file "./ci/lint_imagefile" ./
-
-docker run --rm -v $(pwd):/bitcoin -it bitcoin-linter
+DOCKER_BUILDKIT=1 docker build -t bitcoin-linter --file "./ci/lint_imagefile" ./ && docker run --rm -v $(pwd):/bitcoin -it bitcoin-linter
 ```
 
-After building the container once, you can simply run the last command any time you
-want to lint.
+Building the container can be done every time, because it is fast when the
+result is cached and it prevents issues when the image changes.
 
 
 check-doc.py