A Semantic Versioning Function for the Makefile

I’ve been spending a lot of time in Jenkins lately; most certainly against my will. Jenkins offers all of the downfalls of a decentralized open source project:

• Disjointed road map
• Feature incomplete
• Difficult to decipher UI
• Multiple implementations of the same feature
• Redundant methods within a single feature
• Much much more!

It’s because of this that I’ve had to move a lot of the logic I would normally keep in the pipeline, into the project itself. Such as Semantic Versioning Function:

.PHONY: increment-version
increment-version:
	@echo -n "Add CHANGELOG entry? Y to exit for entry creation [Y/n] " && read ans && [ $${ans:-N} = n ]
	@# evaluate the current version at runtime
	$(eval CURRENT_MAJOR_VERSION := $(shell awk -F'.' '{print FILENAME, $$1}' < VERSION))
	$(eval CURRENT_MINOR_VERSION := $(shell awk -F'.' '{print FILENAME, $$2}' < VERSION))
	$(eval CURRENT_PATCH_VERSION := $(shell awk -F'.' '{print FILENAME, $$3}' < VERSION))
# major
ifeq ($(SEMVER),$(filter $(SEMVER), MAJOR major))
	@echo $$[$(CURRENT_MAJOR_VERSION)+1].$(ZERO).$(ZERO) > VERSION
endif
# minor
ifeq ($(SEMVER),$(filter $(SEMVER), MINOR minor))
	@echo $(CURRENT_MAJOR_VERSION).$$[$(CURRENT_MINOR_VERSION)+1].$(ZERO) > VERSION
endif
# patch
ifeq ($(SEMVER),$(filter $(SEMVER), PATCH patch))
	@echo $(CURRENT_MAJOR_VERSION).$(CURRENT_MINOR_VERSION).$$[$(CURRENT_PATCH_VERSION)+1] > VERSION
endif
	@echo "version updated."

The first prompt asks the user if they want to enter a CHANGELOG entry. If they user answers yes, the make command is exited with an error. This allows the user to make the change to the CHANGELOG before the versioning takes place.

Alternatively, if the user answers that they do not need to enter a CHANGELOG entry, the rest of the command will execute.

This function works in conjunction with a VERSION file which contains a plain Semantic Version such as 0.0.3

make increment-version SEMVER=patch/minor/major

The type of change is set to the SEMVER variable and that prompts the update mechanism to make the corresponding change. For example:

If the current version is 1.0.3 and we run the following command:

make increment-version SEMVER=patch

The resulting version in the VERSION file will be 1.0.4. If we again run the increment-version command:

make increment-version SEMVER=minor

The resulting version then will be 1.1.0. If we run the increment-version command a final time:

make increment-version SEMVER=major

The VERSION file will read 2.0.0

I hope this snippet is useful to someone. I didn’t spend too much time putting it together but it’s, at least, the 10th time I’ve written something like this. /J