How to evaluate a Makefile function outside a target recipe and return a value from the function? - makefile

Question

I needed to checkout a git repository in the Makefile:
REPO_NAME = something
REPO_URL = something
REPO_BRANCH = branch
define clone_repo_function
git -C $(1) init --quiet
git -C $(1) remote add origin $(2)
git -C $(1) fetch origin --progress --quiet --depth 1 $(3)
git -C $(1) reset --quiet --hard FETCH_HEAD
endef
clone_it:
$(call clone_repo_function,$(REPO_NAME),$(REPO_URL),$(REPO_BRANCH))
do-something --input $(REPO_NAME)
And that works OK.
What I want to do is get sha1 value from the repo, so that I know at what point was the REPO_BRANCH used.
So I tried to extend the clone_repo_function with additional parameter number 4 $(REPO_SHA1) and save sha1 into it using git rev-parse HEAD:
REPO_NAME ?= something
REPO_URL ?= something
REPO_BRANCH ?= branch
REPO_SHA1 ?= 123
define clone_repo_function
git -C $(1) init --quiet
git -C $(1) remote add origin $(2)
git -C $(1) fetch origin --progress --quiet --depth 1 $(3)
git -C $(1) reset --quiet --hard FETCH_HEAD
$(4)=$$(shell git rev-parse HEAD)
endef
clone_it:
$(eval $(call clone_repo_function,$(REPO_NAME),$(REPO_URL),$(REPO_BRANCH),$(REPO_SHA1)))
do-something --input $(REPO_NAME) --sha1 $(REPO_SHA1)
However, this of course will not work and gives expected Error: recipe commences before first target.
Is there a proper way to call a function which returns a value, but outside of a make target? And then use the value within some target? Or the problem needs to be addressed in a completely different way.