An unfinished idea I had to generate documentation for tagged releases and extant feature branches

GNUMakefile

# This was inspired by https://www.codingwiththomas.com/blog/my-sphinx-best-practice-for-a-multiversion-documentation-in-different-languages.
# However, I'm taking a different approach.

# Generate documentation for tagged releases and extant feature
# branches.  Take care to handle remote branches, too, not just local
# branches or local remote-tracking branches.  However, do not alter
# the working directory in any way.
docs: $(LOCALES) | $(PYPACKAGE_NAME).egg-info
# Create missing remote-tracking branches.
	LOCAL_BRANCHES=$$(git branch \
		| grep -E -v '^..(HEAD|gh-pages|main|master|releases?(/.*)?)$$' \
		| cut -c 3-); \
	REMOTE_BRANCHES=$$(git branch -r \
		| grep -E -v '^.*/(HEAD|gh-pages|main|master|releases?(/.*)?)$$' \
		| cut -c 3-); \
	for rb in $$REMOTE_BRANCHES; do \
		lb=`echo $$rb | sed -e 's|[^/]*/||'`; \
		echo $$LOCAL_BRANCHES | grep ^$$lb\$$ > /dev/null \
		|| git branch $$lb $$rb; \
	done
# Copy the repository to a temporary directory.  Stash the Sphinx
# configuration from the current working directory for use later.
	$(eval TMP := $(shell mktemp -d))
	echo The temporary directory: $(TMP)
	git clone --mirror . $(TMP)/.git
	cp docs/conf.py $(TMP)/.git
# For each version and translation...
	cd $(TMP); \
	VERSIONS=$$(git tag | sort -r; git branch \
		| grep -E -v '^..(HEAD|gh-pages|main|master|releases?(/.*)?)$$' \
		| cut -c 3-); \
	for v in $$VERSIONS; do \
		env GIT_WORK_TREE=. git checkout $$v; \
		i=0; \
		for l in $(TRANSLATIONS); do \
			((i++)); \
			if [ $$i -gt 1 -a -f docs/_locale/$$l ]; then \
				echo "{
# Clean up.
	rm -rf $(TMP)
#	$(foreach l,$(TRANSLATIONS), \
#		$(SPHINXMULTI) -D language="$(l)" docs build/html/$(l))
#	env LATEST_VERSION=`git describe --tag --abbrev=0` \
#		envsubst < docs/.index.html > build/html/index.html