ci: improve reftable test coverage

The "linux-reftable" job exercises Git with reftables as its default
backend. But this job is arguably redundant because we already have the
"linux-reftable-leaks" job that exercises reftables with the leak
sanitizer enabled, and it is unlikely that we will catch any extra bugs
with the leak sanitizer disabled.

One may thus be triggered to just drop the "linux-reftable" job in favor
of the leak-checking variant. But the latter disables a couple of other
tests that exercise git-p4, git-svn and other tools. Those tools may not
be an essential part of Git nowadays, but I don't quite feel comfortable
with reducing test coverage.

Instead, adapt the job to run reftables together with SHA256. which is
an area that we don't have test coverage for.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

.github/workflows/main.yml

@@ -405,7 +405,7 @@ jobs:
         - jobname: linux-sha256
           image: ubuntu:rolling
           cc: clang
-        - jobname: linux-reftable
+        - jobname: linux-reftable-sha256
           image: ubuntu:rolling
           cc: clang
         - jobname: linux-feature-testbed

.gitlab-ci.yml

@@ -39,7 +39,7 @@ test:linux:
       - jobname: linux-sha256
         image: ubuntu:rolling
         CC: clang
-      - jobname: linux-reftable
+      - jobname: linux-reftable-sha256
         image: ubuntu:rolling
         CC: clang
       - jobname: linux-feature-testbed

ci/run-build-and-tests.sh

@@ -40,10 +40,13 @@ linux-feature-testbed)
 linux-sha256)
 	export GIT_TEST_DEFAULT_HASH=sha256
 	;;
-linux-reftable|linux-reftable-leaks|osx-reftable)
+linux-reftable-sha256)
+	export GIT_TEST_DEFAULT_REF_FORMAT=reftable
+	export GIT_TEST_DEFAULT_HASH=sha256
+	;;
+linux-reftable-leaks|osx-reftable)
 	export GIT_TEST_DEFAULT_REF_FORMAT=reftable
 	;;
-
 esac
 
 case "$jobname" in