Makefile: add a few new targets to streamline my release workflow

Signed-off-by: Elijah Newren <newren@gmail.com>

Makefile

@@ -38,3 +38,88 @@ install: snag_docs #fixup_locale
 	ln -s $(bindir)/git-filter-repo $(pythondir)/git_filter_repo.py
 	cp -a Documentation/man1/git-filter-repo.1 $(mandir)/man1/git-filter-repo.1
 	cp -a Documentation/html/git-filter-repo.html $(htmldir)/git-filter-repo.html
+
+
+#
+# The remainder of the targets are meant for tasks for the maintainer; if they
+# don't work for you, I don't care.  These tasks modify branches and upload
+# releases and whatnot, and presume a directory layout I have locally.
+#
+update_docs: export GIT_WORK_TREE=$(shell mktemp -d)
+update_docs: export GIT_INDEX_FILE=$(shell mktemp)
+update_docs: export COMMIT=$(shell git rev-parse HEAD)
+update_docs:
+	# Sanity check; we'll build docs in a clone of a git repo
+	test -d ../git
+	# Avoid spurious errors by forcing index to be well formatted, if empty
+	git read-tree 4b825dc642cb6eb9a060e54bf8d69288fbee4904 # empty tree
+	# Symlink git-filter-repo.txt documentation into git and build it
+	ln -sf ../../git-filter-repo/Documentation/git-filter-repo.txt ../git/Documentation/
+	make -C ../git/Documentation -j4 man html
+	# Take the built documentation and lay it out nicely
+	mkdir $$GIT_WORK_TREE/html
+	mkdir $$GIT_WORK_TREE/man1
+	cp -a ../git/Documentation/*.html $$GIT_WORK_TREE/html/
+	cp -a ../git/Documentation/git-filter-repo.1 $$GIT_WORK_TREE/man1/
+	dos2unix $$GIT_WORK_TREE/html/*
+	# Add new version of the documentation as a commit, if it differs
+	git --work-tree $$GIT_WORK_TREE add .
+	git diff --quiet docs || git write-tree \
+		| xargs git commit-tree -p docs -m "Update docs to $$COMMIT" \
+		| xargs git update-ref refs/heads/docs
+	# Remove temporary files
+	rm -rf $$GIT_WORK_TREE
+	rm $$GIT_INDEX_FILE
+	# Push the new documentation upstream
+	git push origin docs
+	# Notify of completion
+	@echo
+	@echo === filter-repo docs branch updated ===
+
+# Call like this:
+#   make GITHUB_COM_TOKEN=$KEY TAGNAME=v2.23.0 release
+release: export FILEBASE=git-filter-repo-$(shell echo $(TAGNAME) | tail -c +2)
+release: export GIT_INDEX_FILE=$(shell mktemp)
+release: export COMMIT=$(shell git rev-parse HEAD)
+release: update_docs
+	test -n "$(GITHUB_COM_TOKEN)"
+	test -n "$(TAGNAME)"
+	test -n "$$COMMIT"
+	# Tag the release, push it to GitHub
+	git tag -a -m "filter-repo $(TAGNAME)" $(TAGNAME) $$COMMIT
+	git push origin $(TAGNAME)
+	# Create the tarball
+	git read-tree $$COMMIT
+	git ls-tree -r docs | grep filter-repo    \
+		| sed -e 's%\t%\tDocumentation/%' \
+		| git update-index --index-info
+	git write-tree                                    \
+		| xargs git archive --prefix=$(FILEBASE)/ \
+		| xz -c >$(FILEBASE).tar.xz
+	rm $$GIT_INDEX_FILE
+	# Make GitHub mark our new tag as an official release
+	curl -s -H "Authorization: token $(TOKEN)" -X POST \
+		https://api.github.com/repos/newren/git-filter-repo/releases \
+		--data "{                                  \
+		  \"tag_name\": \"$(TAGNAME)\",            \
+		  \"target_commitish\": \"$$COMMIT\",      \
+		  \"name\": \"$(TAGNAME)\",                \
+		  \"body\": \"filter-repo $(TAGNAME)\"     \
+		}" | jq -r .id >asset_id
+	# Upload our tarball
+	cat asset_id | xargs -I ASSET_ID curl -s -H "Authorization: token $(TOKEN)" -H "Content-Type: application/octet-stream" --data-binary @$(FILEBASE).tar.xz https://uploads.github.com/repos/newren/git-filter-repo/releases/ASSET_ID/assets?name=$(FILEBASE).tar.xz
+	# Remove temporary file(s)
+	rm asset_id
+	# Notify of completion
+	@echo
+	@echo === filter-repo $(TAGNAME) created and uploaded to GitHub ===
+
+# NOTE TO FUTURE SELF: If you accidentally push a bad release, you can remove
+# all but the git-filter-repo-$VERSION.tar.xz asset with
+#    git push --delete origin $TAGNAME
+# To remove the git-filter-repo-$VERSION.tar.xz asset as well:
+#    curl -s -H "Authorization: token $GITHUB_COM_TOKEN" -X GET \
+#        https://api.github.com/repos/newren/git-filter-repo/releases
+# and look for the "id", then run
+#    curl -s -H "Authorization: token $GITHUB_COM_TOKEN" -X DELETE \
+#        https://api.github.com/repos/newren/git-filter-repo/releases/$ID