Merge pull request #55 from wentasah/gitversion

Allow creating release source code archives with make release

Makefile

@@ -32,15 +32,23 @@ usbrelay: usbrelay.c libusbrelay.h libusbrelay.so
 
 python:
 	$(MAKE) -C usbrelay_py
-# Command to generate version number if running from git repo
-DIR_VERSION = $(shell basename `pwd`)
-GIT_VERSION = $(shell git describe --tags --match '[0-9].[0-9]*' --abbrev=10 --dirty)
+
+# Commands to generate version number in various situations
+# - Release tarballs have version.mk
+REL_VERSION = $(if $(wildcard version.mk),$(shell cat version.mk))
+# - Use version reported by git
+GIT_VERSION = $(if $(wildcard .git/HEAD .git/index),$(shell git describe --tags --match '[0-9].[0-9]*' --abbrev=10 --dirty))
+# - Fall back to version derived from directory name
+DIR_VERSION = $(shell echo $(notdir $(CURDIR)) | sed -nEe 's/usbrelay-([0-9].*)/\1/p')
+
+# Use first version, which is not empty
+VERSION=$(or $(REL_VERSION),$(GIT_VERSION),$(DIR_VERSION),unknown)
 
 # If .git/HEAD and/or .git/index exist, we generate git version with
 # the command above and regenerate it whenever any of these files
 # changes. If these files don't exist, we use ??? as the version.
 gitversion.h: $(wildcard .git/HEAD .git/index)
-	echo "#define GITVERSION \"$(if $(word 1,$^),$(GIT_VERSION),$(DIR_VERSION))\"" > $@
+	echo "#define GITVERSION \"$(VERSION)\"" > $@
 
 usbrelay.c libusbrelay.c: gitversion.h
 
@@ -62,4 +70,36 @@ install: usbrelay libusbrelay.so
 install_py:
 	$(MAKE) -C usbrelay_py install
 
-.PHONY: all clean install
+# Release target for maintainers
+#
+# The goal is to generate a commit which contains version.mk with the
+# version number, but not have this file in subsequent commits.
+release:
+	@if [ -z "$(VER)" ]; then echo "Please specify version to release, e.g., 'make release VER=1.2.3'."; exit 1; fi
+	@if [ -n "$$(git tag -l '$(VER)')" ]; then echo ''Tag $(VER) already exists.''; exit 1; fi
+	git diff --stat --exit-code HEAD # Check that there are no uncommitted changes
+	echo $(VER) > version.mk
+	git add version.mk
+	git commit -m "Release $(VER)"
+	git tag -m "Release $(VER)" --sign $(VER)
+	git reset --keep HEAD^
+	git merge --strategy ours -m 'Remove version.mk after release' $(VER)
+	@echo
+	@echo "Now run 'git push --follow-tags' and create the release on GitHub."
+	@echo "Then, you can sign the release archives by 'make sign-release VER=$(VER)'"
+
+# Sign the release tarball after its creation on GitHub. This is based
+# on https://wiki.debian.org/Creating%20signed%20GitHub%20releases. In
+# addition to that, we use the 'gh' tool to automate downloading of
+# the tarball and uploading of the signature.
+sign-release:
+	@if [ -z "$(VER)" ]; then echo "Please specify the release to sign, e.g., 'make sign-release VER=1.2.3'."; exit 1; fi
+	git archive --prefix='usbrelay-$(VER)/' -o 'usbrelay-$(VER).tar.gz' '$(VER)'
+	gpg --armor --detach-sign 'usbrelay-$(VER).tar.gz'
+# Verify that github has the same tarball
+	rm -f 'usbrelay-$(VER).tar.gz'
+	gh release download '$(VER)' --archive=tar.gz
+	gpg --verify 'usbrelay-$(VER).tar.gz.asc'
+	gh release upload '$(VER)' 'usbrelay-$(VER).tar.gz.asc'
+
+.PHONY: all clean install release sign-release