Merge bitcoin/bitcoin#26906: test: add an easy way to run linters locally

b68e5a7feff3e93027e75da0cd9a590fef99aac1 lint: specify the right commit range when running locally (James O'Beirne)
dff7ed5732c01b3ba47ef9e9ddb687d073d7739d test: add an easy way to run linters locally (James O'Beirne)

Pull request description:

  Adds a Dockerfile configuration ~~(originally written mostly by fanquake)~~ that allows straightforward running of linters with compatible versions locally. This removes a ton of annoyance when trying to appease CI, because many of the linter versions are quite old and difficult to maintain locally.

  I realize that people may not be thrilled to add more ancillary tooling to the repo, but I think this makes a lot of sense given the linter versions listed in this container configuration are dictated by this repo (within the CI configuration), so having these things live in two separate places is a recipe for version mismatches.

  Eventually we can likely just use this container on CI directly to avoid any chance of inconsistencies between local dev experience and CI.

ACKs for top commit:
  aureleoules:
    ACK b68e5a7feff3e93027e75da0cd9a590fef99aac1
  stickies-v:
    ACK b68e5a7fe
  john-moffett:
    ACK b68e5a7feff3e93027e75da0cd9a590fef99aac1

Tree-SHA512: 7ef7a5dae023d81fdb6296d5d92dfa074ee321c7993e607c9f014d0f21c91558611aa00fc3ce1edc7b5e68371aea0d27fa1931291a79bb867a6c783bb536775f

4 files changed, 67 insertions, 19 deletions

diff --git a/ci/lint/04_install.sh b/ci/lint/04_install.sh
index 4ad1ec2fd3..f7147582dc 100755
--- a/ci/lint/04_install.sh
+++ b/ci/lint/04_install.sh
@@ -13,23 +13,25 @@ ${CI_RETRY_EXE} apt-get update
 # - gpg (used by verify-commits)
 ${CI_RETRY_EXE} apt-get install -y curl xz-utils git gpg
 
-PYTHON_PATH=/tmp/python
-if [ ! -d "${PYTHON_PATH}/bin" ]; then
-  (
-    git clone https://github.com/pyenv/pyenv.git
-    cd pyenv/plugins/python-build || exit 1
-    ./install.sh
-  )
-  # For dependencies see https://github.com/pyenv/pyenv/wiki#suggested-build-environment
-  ${CI_RETRY_EXE} apt-get install -y build-essential libssl-dev zlib1g-dev \
-    libbz2-dev libreadline-dev libsqlite3-dev curl llvm \
-    libncursesw5-dev xz-utils tk-dev libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev \
-    clang
-  env CC=clang python-build "$(cat "${BASE_ROOT_DIR}/.python-version")" "${PYTHON_PATH}"
+if [ -z "${SKIP_PYTHON_INSTALL}" ]; then
+    PYTHON_PATH=/tmp/python
+    if [ ! -d "${PYTHON_PATH}/bin" ]; then
+      (
+        git clone https://github.com/pyenv/pyenv.git
+        cd pyenv/plugins/python-build || exit 1
+        ./install.sh
+      )
+      # For dependencies see https://github.com/pyenv/pyenv/wiki#suggested-build-environment
+      ${CI_RETRY_EXE} apt-get install -y build-essential libssl-dev zlib1g-dev \
+        libbz2-dev libreadline-dev libsqlite3-dev curl llvm \
+        libncursesw5-dev xz-utils tk-dev libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev \
+        clang
+      env CC=clang python-build "$(cat "${BASE_ROOT_DIR}/.python-version")" "${PYTHON_PATH}"
+    fi
+    export PATH="${PYTHON_PATH}/bin:${PATH}"
+    command -v python3
+    python3 --version
 fi
-export PATH="${PYTHON_PATH}/bin:${PATH}"
-command -v python3
-python3 --version
 
 ${CI_RETRY_EXE} pip3 install codespell==2.2.1
 ${CI_RETRY_EXE} pip3 install flake8==5.0.4
@@ -38,5 +40,6 @@ ${CI_RETRY_EXE} pip3 install pyzmq==24.0.1
 ${CI_RETRY_EXE} pip3 install vulture==2.6
 
 SHELLCHECK_VERSION=v0.8.0
-curl -sL "https://github.com/koalaman/shellcheck/releases/download/${SHELLCHECK_VERSION}/shellcheck-${SHELLCHECK_VERSION}.linux.x86_64.tar.xz" | tar --xz -xf - --directory /tmp/
-export PATH="/tmp/shellcheck-${SHELLCHECK_VERSION}:${PATH}"
+curl -sL "https://github.com/koalaman/shellcheck/releases/download/${SHELLCHECK_VERSION}/shellcheck-${SHELLCHECK_VERSION}.linux.x86_64.tar.xz" | \
+    tar --xz -xf - --directory /tmp/
+mv "/tmp/shellcheck-${SHELLCHECK_VERSION}/shellcheck" /usr/bin/
diff --git a/ci/lint/06_script.sh b/ci/lint/06_script.sh
index c14d7473d3..fa28f6126c 100755
--- a/ci/lint/06_script.sh
+++ b/ci/lint/06_script.sh
@@ -6,7 +6,11 @@
 
 export LC_ALL=C
 
-if [ -n "$CIRRUS_PR" ]; then
+if [ -n "$LOCAL_BRANCH" ]; then
+  # To faithfully recreate CI linting locally, specify all commits on the current
+  # branch.
+  COMMIT_RANGE="$(git merge-base HEAD master)..HEAD"
+elif [ -n "$CIRRUS_PR" ]; then
   COMMIT_RANGE="HEAD~..HEAD"
   echo
   git log --no-merges --oneline "$COMMIT_RANGE"
diff --git a/ci/lint/Dockerfile b/ci/lint/Dockerfile
new file mode 100644
index 0000000000..03c20c7286
--- /dev/null
+++ b/ci/lint/Dockerfile
@@ -0,0 +1,29 @@
+# See test/lint/README.md for usage.
+#
+# This container basically has to live in this directory in order to pull in the CI
+# install scripts. If it lived in the root directory, it would have to pull in the
+# entire repo as docker context during build; if it lived elsewhere, it wouldn't be
+# able to make back-references to pull in the install scripts. So here it lives.
+
+FROM python:3.7-buster
+
+ENV DEBIAN_FRONTEND=noninteractive
+ENV LC_ALL=C.UTF-8
+
+# This is used by the 04_install.sh script; we can't read the Python version from
+# .python-version for the same reasons as above, and it's more efficient to pull a
+# preexisting Python image than it is to build from source.
+ENV SKIP_PYTHON_INSTALL=1
+
+# Must be built from ./ci/lint/ for these paths to work.
+COPY ./docker-entrypoint.sh /entrypoint.sh
+COPY ./04_install.sh /install.sh
+
+RUN /install.sh && \
+  echo 'alias lint="./ci/lint/06_script.sh"' >> ~/.bashrc && \
+  chmod 755 /entrypoint.sh && \
+  rm -rf /var/lib/apt/lists/*
+
+
+WORKDIR /bitcoin
+ENTRYPOINT ["/entrypoint.sh"]
diff --git a/ci/lint/docker-entrypoint.sh b/ci/lint/docker-entrypoint.sh
new file mode 100755
index 0000000000..3fdbbb0761
--- /dev/null
+++ b/ci/lint/docker-entrypoint.sh
@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+export LC_ALL=C
+
+# Fixes permission issues when there is a container UID/GID mismatch with the owner
+# of the mounted bitcoin src dir.
+git config --global --add safe.directory /bitcoin
+
+if [ -z "$1" ]; then
+  LOCAL_BRANCH=1 bash -ic "./ci/lint/06_script.sh"
+else
+  exec "$@"
+fi