[PATCH v2 1/1] Makefile: add a prerequisite to the coverage-report target

[Elia Pinto <gitter.spiros@gmail.com>]

Directly invoking make coverage-report as a target results in an error because
its prerequisites are missing,

This patch adds the compile-test prerequisite, which is run only once each time
the compile-report target is invoked. In practice, the developer may decide to
review the coverage-report results without necessarily rerunning for this
coverage-test, if it has already been run.

Signed-off-by: Elia Pinto <gitter.spiros@gmail.com>
---
This is the second version of the patch.

With respect to the first version, we tried to eliminate the inefficient
coverage-test invocation if the target is coverage-report, introducing a more
useful invocation order

 Makefile | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index e8aba291d7..eacdffd748 100644
--- a/Makefile
+++ b/Makefile
@@ -3378,6 +3378,8 @@ check-builtins::
 .PHONY: coverage-untested-functions cover_db cover_db_html
 .PHONY: coverage-clean-results
 
+coverage-test.file?=coverage-test.file
+
 coverage:
 	$(MAKE) coverage-test
 	$(MAKE) coverage-untested-functions
@@ -3389,6 +3391,7 @@ coverage-clean-results:
 	$(RM) coverage-untested-functions
 	$(RM) -r cover_db/
 	$(RM) -r cover_db_html/
+	$(RM) -f $(coverage-test.file)
 
 coverage-clean: coverage-clean-results
 	$(RM) $(addsuffix *.gcno,$(object_dirs))
@@ -3404,12 +3407,16 @@ coverage-test: coverage-clean-results coverage-compile
 	$(MAKE) CFLAGS="$(COVERAGE_CFLAGS)" LDFLAGS="$(COVERAGE_LDFLAGS)" \
 		DEFAULT_TEST_TARGET=test -j1 test
 
+$(coverage-test.file):
+	@make coverage-test
+	touch $(coverage-test.file)
+
 coverage-prove: coverage-clean-results coverage-compile
 	$(MAKE) CFLAGS="$(COVERAGE_CFLAGS)" LDFLAGS="$(COVERAGE_LDFLAGS)" \
 		DEFAULT_TEST_TARGET=prove GIT_PROVE_OPTS="$(GIT_PROVE_OPTS) -j1" \
 		-j1 test
 
-coverage-report:
+coverage-report: $(coverage-test.file)
 	$(QUIET_GCOV)for dir in $(object_dirs); do \
 		$(GCOV) $(GCOVFLAGS) --object-directory=$$dir $$dir*.c || exit; \
 	done
-- 
2.35.1