Makefile: remove check2 and references to python2

.github/workflows/ci.yml

@@ -1,7 +1,7 @@
 name: ci
 on: [pull_request, workflow_dispatch]
 jobs:
-  check3:
+  check:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
@@ -13,7 +13,7 @@ jobs:
           # -common seems a catch-22, but this is just a shortcut to
           # initialize user and dirs, some used through tests.
           sudo apt-get -y install landscape-common
-      - run: make check3 TRIAL=/usr/bin/trial3
+      - run: make check TRIAL=/usr/bin/trial3
   lint:
     runs-on: ubuntu-latest
     steps:

Makefile

@@ -1,10 +1,10 @@
 PYDOCTOR ?= pydoctor
 TXT2MAN ?= txt2man
-PYTHON2 ?= python2
-PYTHON3 ?= python3
+PYTHON ?= python3
 SNAPCRAFT = SNAPCRAFT_BUILD_INFO=1 snapcraft
 TRIAL ?= -m twisted.trial
 TRIAL_ARGS ?=
+PRE_COMMIT ?= $(HOME)/.local/bin/pre-commit
 
 # PEP8 rules ignored:
 # W503 https://www.flake8rules.com/rules/W503.html
@@ -16,57 +16,34 @@ help:  ## Print help about available targets
 	@grep -h -E '^[a-zA-Z0-9_-]+:.*?## .*$$' $(MAKEFILE_LIST) | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-20s\033[0m %s\n", $$1, $$2}'
 
 .PHONY: depends
-depends: depends3  ## py2 is deprecated
-	sudo apt-get -y install python3-flake8 python3-coverage
-
-.PHONY: depends2
-depends2:
-	sudo apt-get -y install python-twisted-core python-distutils-extra python-mock python-configobj python-netifaces python-pycurl python-pip
+depends:
+	sudo apt-get -y install python3-configobj python3-coverage python3-distutils-extra\
+		python3-flake8 python3-mock python3-netifaces python3-pip python3-pycurl python3-twisted
 	pip install pre-commit
-	pre-commit install
-
-.PHONY: depends3
-depends3:
-	sudo apt-get -y install python3-twisted python3-distutils-extra python3-mock python3-configobj python3-netifaces python3-pycurl python3-pip
-	pip3 install pre-commit
-	pre-commit install
+	$(PRE_COMMIT) install
 
 all: build
 
 .PHONY: build
-build: build2 build3   ## Build.
-
-.PHONY: build2
-build2:
-	$(PYTHON2) setup.py build_ext -i
-
-.PHONY: build3
-build3:
-	$(PYTHON3) setup.py build_ext -i
-
-.PHONY: check
-check: check2 check3  ## Run all the tests.
-
-.PHONY: check2
-check2: build2
-	PYTHONPATH=$(PYTHONPATH):$(CURDIR) LC_ALL=C $(PYTHON2) $(TRIAL) --unclean-warnings $(TRIAL_ARGS) landscape
+build:
+	$(PYTHON) setup.py build_ext -i
 
 # trial3 does not support threading via `-j` at the moment
 # so we ignore TRIAL_ARGS.
 # TODO: Respect $TRIAL_ARGS once trial3 is fixed.
-.PHONY: check3
-check3: TRIAL_ARGS=
-check3: build3
-	PYTHONPATH=$(PYTHONPATH):$(CURDIR) LC_ALL=C $(PYTHON3) $(TRIAL) --unclean-warnings $(TRIAL_ARGS) landscape
+.PHONY: check
+check: TRIAL_ARGS=
+check: build
+	PYTHONPATH=$(PYTHONPATH):$(CURDIR) LC_ALL=C $(PYTHON) $(TRIAL) --unclean-warnings $(TRIAL_ARGS) landscape
 
 .PHONY: coverage
 coverage:
-	PYTHONPATH=$(PYTHONPATH):$(CURDIR) LC_ALL=C $(PYTHON3) -m coverage run $(TRIAL) --unclean-warnings landscape
-	PYTHONPATH=$(PYTHONPATH):$(CURDIR) LC_ALL=C $(PYTHON3) -m coverage xml
+	PYTHONPATH=$(PYTHONPATH):$(CURDIR) LC_ALL=C $(PYTHON) -m coverage run $(TRIAL) --unclean-warnings landscape
+	PYTHONPATH=$(PYTHONPATH):$(CURDIR) LC_ALL=C $(PYTHON) -m coverage xml
 
 .PHONY: lint
 lint:
-	$(PYTHON3) -m flake8 --ignore $(PEP8_IGNORED) `find landscape -name \*.py`
+	$(PYTHON) -m flake8 --ignore $(PEP8_IGNORED) `find landscape -name \*.py`
 
 .PHONY: pyflakes
 pyflakes: