improve release setup based on the one in GitPython

.gitignore

@@ -9,3 +9,4 @@ MANIFEST
 *.egg-info
 .noseids
 *.sublime-workspace
+/env/

Makefile

@@ -1,49 +1,12 @@
-.PHONY: build sdist cover test clean-files clean-docs doc all  
+.PHONY: all clean release force_release
 
 all:
-	$(info Possible targets:)
-	$(info doc)
-	$(info clean-docs)
-	$(info clean-files)
-	$(info clean)
-	$(info test)
-	$(info coverage)
-	$(info build)
-	$(info sdist)
+	@grep -Ee '^[a-z].*:' Makefile | cut -d: -f1 | grep -vF all
 
-doc:
-	cd doc && make html
+clean:
+	rm -rf build/ dist/ .eggs/ .tox/
 
-clean-docs:
-	cd doc && make clean
-
-clean-files:
-	git clean -fx
-	rm -rf build/ dist/
-
-clean: clean-files clean-docs
-
-test:
-	pytest
-
-coverage:
-	pytest --cov smmap --cov-report xml
-
-build:
-	./setup.py build
-
-sdist:
-	./setup.py sdist
-
-release: clean
-	# Check if latest tag is the current head we're releasing
-	echo "Latest tag = $$(git tag | sort -nr | head -n1)"
-	echo "HEAD SHA       = $$(git rev-parse head)"
-	echo "Latest tag SHA = $$(git tag | sort -nr | head -n1 | xargs git rev-parse)"
-	@test "$$(git rev-parse head)" = "$$(git tag | sort -nr | head -n1 | xargs git rev-parse)"
-	make force_release
-
-force_release:: clean
-	git push --tags
-	python3 setup.py sdist bdist_wheel
+force_release: clean
+	./build-release.sh
 	twine upload dist/*
+	git push --tags origin main

build-release.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+#
+# This script builds a release. If run in a venv, it auto-installs its tools.
+# You may want to run "make release" instead of running this script directly.
+
+set -eEu
+
+function release_with() {
+    $1 -m build --sdist --wheel
+}
+
+if test -n "${VIRTUAL_ENV:-}"; then
+    deps=(build twine)  # Install twine along with build, as we need it later.
+    echo "Virtual environment detected. Adding packages: ${deps[*]}"
+    pip install --quiet --upgrade "${deps[@]}"
+    echo 'Starting the build.'
+    release_with python
+else
+    function suggest_venv() {
+        venv_cmd='python -m venv env && source env/bin/activate'
+        printf "HELP: To avoid this error, use a virtual-env with '%s' instead.\n" "$venv_cmd"
+    }
+    trap suggest_venv ERR  # This keeps the original exit (error) code.
+    echo 'Starting the build.'
+    release_with python3 # Outside a venv, use python3.
+fi