Drop Python 3.7 support

Dropping `3.7` as announced here:
https://github.blog/changelog/2023-08-02-deprecation-notice-dependabot-to-drop-support-for-python-3-6-and-3-7/

python/Dockerfile

@@ -4,15 +4,13 @@ ARG PY_3_11=3.11.4
 ARG PY_3_10=3.10.12
 ARG PY_3_9=3.9.17
 ARG PY_3_8=3.8.17
-ARG PY_3_7=3.7.17
 ARG PYENV_VERSION=v2.3.19
 
 FROM ghcr.io/dependabot/dependabot-updater-core as python-core
 ARG PY_3_11
 ARG PY_3_10
 ARG PY_3_9
 ARG PY_3_8
-ARG PY_3_7
 ARG PYENV_VERSION
 USER root
 
@@ -74,13 +72,6 @@ RUN pyenv install $PY_3_8 \
  && cd /usr/local/.pyenv \
  && tar czf 3.8.tar.gz versions/$PY_3_8
 
-FROM python-core as python-3.7
-RUN pyenv install $PY_3_7 \
- && bash /opt/python/helpers/build $PY_3_7 \
- && cd /usr/local/.pyenv \
- && tar czf 3.7.tar.gz versions/$PY_3_7
-
-
 FROM ghcr.io/dependabot/dependabot-updater-core
 ARG PY_3_11
 ARG PYENV_VERSION
@@ -132,7 +123,6 @@ RUN pyenv install $PY_3_11 \
 COPY --from=python-3.10 /usr/local/.pyenv/3.10.tar.gz /usr/local/.pyenv/3.10.tar.gz
 COPY --from=python-3.9 /usr/local/.pyenv/3.9.tar.gz /usr/local/.pyenv/3.9.tar.gz
 COPY --from=python-3.8 /usr/local/.pyenv/3.8.tar.gz /usr/local/.pyenv/3.8.tar.gz
-COPY --from=python-3.7 /usr/local/.pyenv/3.7.tar.gz /usr/local/.pyenv/3.7.tar.gz
 
 COPY --chown=dependabot:dependabot python $DEPENDABOT_HOME/python
 COPY --chown=dependabot:dependabot common $DEPENDABOT_HOME/common

python/lib/dependabot/python/language_version_manager.rb

@@ -12,7 +12,6 @@ class LanguageVersionManager
  3.10.12
  3.9.17
  3.8.17
- 3.7.17
  ).freeze
 
  def initialize(python_requirement_parser:)

python/lib/dependabot/python/update_checker/pip_compile_version_resolver.rb

@@ -22,7 +22,6 @@ class UpdateChecker
  # This class does version resolution for pip-compile. Its approach is:
  # - Unlock the dependency we're checking in the requirements.in file
  # - Run `pip-compile` and see what the result is
- # rubocop:disable Metrics/ClassLength
  class PipCompileVersionResolver
  GIT_DEPENDENCY_UNREACHABLE_REGEX = /git clone --filter=blob:none --quiet (?<url>[^\s]+).* /
  GIT_REFERENCE_NOT_FOUND_REGEX = /Did not find branch or tag '(?<tag>[^\n"]+)'/m
@@ -235,10 +234,6 @@ def run_command(command, env: python_env, fingerprint:)
  )
  end
 
- def new_resolver_supported?
- language_version_manager.python_version >= Python::Version.new("3.7")
- end
-
  def pip_compile_options_fingerprint(options)
  options.sub(
  /--output-file=\S+/, "--output-file=<output_file>"
@@ -252,8 +247,12 @@ def pip_compile_options_fingerprint(options)
  def pip_compile_options(filename)
  options = @build_isolation ? ["--build-isolation"] : ["--no-build-isolation"]
  options += pip_compile_index_options
+ # TODO: Stop explicitly specifying `allow-unsafe` once it becomes the default:
+ # https://github.com/jazzband/pip-tools/issues/989#issuecomment-1661254701
  options += ["--allow-unsafe"]
- options += ["--resolver backtracking"] if new_resolver_supported?
+ # TODO: This is the default as of https://github.com/jazzband/pip-tools/releases/tag/7.0.0
+ # so stop explicitly specifying it as soon as we upgrade
+ options += ["--resolver backtracking"]
 
  if (requirements_file = compiled_file_for_filename(filename))
  options << "--output-file=#{requirements_file.name}"
@@ -501,7 +500,6 @@ def setup_cfg_files
  dependency_files.select { |f| f.name.end_with?("setup.cfg") }
  end
  end
- # rubocop:enable Metrics/ClassLength
  end
  end
 end

python/spec/dependabot/python/update_checker/pip_version_resolver_spec.rb

@@ -44,7 +44,7 @@
  content: python_version_content
  )
  end
- let(:python_version_content) { "3.7.0\n" }
+ let(:python_version_content) { "3.11.0\n" }
  let(:pypi_response) { fixture("pypi", "pypi_simple_response_django.html") }
  let(:pypi_url) { "https://pypi.org/simple/django/" }
  let(:dependency) do
@@ -81,16 +81,16 @@
  it { is_expected.to eq(Gem::Version.new("3.2.4")) }
 
  context "that is set to the oldest version of python supported by Dependabot" do
- let(:python_version_content) { "3.7.0\n" }
+ let(:python_version_content) { "3.8.0\n" }
  it { is_expected.to eq(Gem::Version.new("3.2.4")) }
  end
 
  context "that is set to a python version no longer supported by Dependabot" do
- let(:python_version_content) { "3.6.0\n" }
+ let(:python_version_content) { "3.7.0\n" }
  it "raises a helpful error" do
  expect { subject }.to raise_error(Dependabot::DependencyFileNotResolvable) do |err|
  expect(err.message).to start_with(
- "Dependabot detected the following Python requirement for your project: '3.6.0'."
+ "Dependabot detected the following Python requirement for your project: '3.7.0'."
  )
  end
  end
@@ -126,17 +126,17 @@
  it { is_expected.to eq(Gem::Version.new("2.1.1")) }
 
  context "that is set to the oldest version of python supported by Dependabot" do
- let(:python_version_content) { "3.7.0\n" }
+ let(:python_version_content) { "3.8.0\n" }
  it { is_expected.to eq(Gem::Version.new("2.1.1")) }
  end
 
  context "that is set to a python version no longer supported by Dependabot" do
- let(:python_version_content) { "3.6.0\n" }
+ let(:python_version_content) { "3.7.0\n" }
 
  it "raises a helpful error" do
  expect { subject }.to raise_error(Dependabot::DependencyFileNotResolvable) do |err|
  expect(err.message).to start_with(
- "Dependabot detected the following Python requirement for your project: '3.6.0'."
+ "Dependabot detected the following Python requirement for your project: '3.7.0'."
  )
  end
  end

python/spec/dependabot/python/update_checker_spec.rb

@@ -200,7 +200,7 @@
  content: python_version_content
  )
  end
- let(:python_version_content) { "3.7.0\n" }
+ let(:python_version_content) { "3.11.0\n" }
  let(:pypi_response) do
  fixture("pypi", "pypi_simple_response_django.html")
  end
@@ -219,16 +219,16 @@
  it { is_expected.to eq(Gem::Version.new("3.2.4")) }
 
  context "that is set to the oldest version of python supported by Dependabot" do
- let(:python_version_content) { "3.7.0\n" }
+ let(:python_version_content) { "3.8.0\n" }
  it { is_expected.to eq(Gem::Version.new("3.2.4")) }
  end
 
  context "that is set to a python version no longer supported by Dependabot" do
- let(:python_version_content) { "3.6.0\n" }
+ let(:python_version_content) { "3.7.0\n" }
  it "raises a helpful error" do
  expect { subject }.to raise_error(Dependabot::DependencyFileNotResolvable) do |err|
  expect(err.message).to start_with(
- "Dependabot detected the following Python requirement for your project: '3.6.0'."
+ "Dependabot detected the following Python requirement for your project: '3.7.0'."
  )
  end
  end