CI: fix the ABI check job, it was using the wrong HEAD

The ABI job git cloned from upstream and then compared HEAD with the
last ABI break. Problem though: the HEAD was origin/main, not the actual
HEAD from the merge request.

Fix this by adding upstream as a remote and fetching from it. And while
we're there update to the last ABI break commit sha and move the
abicheck bits into before_script.

Note that the remote has the CI job ID appended, this avoids conflicts
when the git repo is re-used betweenn jobs and the upstream remote
already exists.

.gitlab-ci.yml

@@ -276,9 +276,8 @@ abicheck@fedora:38:
   extends:
     - .fedora-build@template
   variables:
-    GIT_STRATEGY: none  # We need the upstream repo instead
     MESON_ARGS: '-Dwerror=true'
-  script:
+  before_script:
     - git clone --depth=1 https://gitlab.freedesktop.org/hadess/check-abi
     - |
       pushd check-abi
@@ -286,10 +285,10 @@ abicheck@fedora:38:
       meson compile -C _build
       meson install -C _build
       popd
-    - git clone --depth=1 https://gitlab.freedesktop.org/$FDO_UPSTREAM_REPO
-    - cd libei
-    - git fetch --tags
-    - check-abi 0.99.1 HEAD
+  script:
+    - git remote add upstream$CI_JOB_ID https://gitlab.freedesktop.org/$FDO_UPSTREAM_REPO
+    - git fetch --tags upstream$CI_JOB_ID
+    - check-abi 168de89a70deb173a32b58b313ddc0aa13310f9a $CI_COMMIT_SHA
   only:
     - merge_requests
 

.gitlab-ci/ci.template

@@ -276,9 +276,8 @@ abicheck@{{distro.name}}:{{version}}:
   extends:
     - .{{distro.name}}-build@template
   variables:
-    GIT_STRATEGY: none  # We need the upstream repo instead
     MESON_ARGS: '-Dwerror=true'
-  script:
+  before_script:
     - git clone --depth=1 https://gitlab.freedesktop.org/hadess/check-abi
     - |
       pushd check-abi
@@ -286,10 +285,10 @@ abicheck@{{distro.name}}:{{version}}:
       meson compile -C _build
       meson install -C _build
       popd
-    - git clone --depth=1 https://gitlab.freedesktop.org/$FDO_UPSTREAM_REPO
-    - cd libei
-    - git fetch --tags
-    - check-abi {{last_abi_break}} HEAD
+  script:
+    - git remote add upstream$CI_JOB_ID https://gitlab.freedesktop.org/$FDO_UPSTREAM_REPO
+    - git fetch --tags upstream$CI_JOB_ID
+    - check-abi {{last_abi_break}} $CI_COMMIT_SHA
   only:
     - merge_requests
 

.gitlab-ci/config.yml

@@ -5,7 +5,7 @@
 # We're happy to rebuild all containers when one changes.
 .default_tag: &default_tag '2023-05-25.0'
 
-last_abi_break: 0.99.1
+last_abi_break: 168de89a70deb173a32b58b313ddc0aa13310f9a
 minimum_meson_version: 0.56.0
 
 distributions: