[PATCH 2/4] CI: default CACHE_DIR to CI_PROJECT_DIR

Set the default cache directory to be the build tree so we don't assume
anything about the runner environment by default.

After this change, runners that don't set CACHE_DIR will need to set it
explicltly in their variables.

Signed-off-by: Ross Burton <[email protected]>
---
 .gitlab-ci.yml | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 577935366e..5861dcf408 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -9,8 +9,10 @@ variables:
   CPU_REQUEST: ""
   # The default machine tag for the build jobs
   DEFAULT_TAG: ""
-  # The directory to use as the persistent cache (the root for DL_DIR, S=
STATE_DIR, etc)
-  CACHE_DIR: $CI_BUILDS_DIR/persist
+  # The directory to use as the persistent cache (the root for DL_DIR,
+  # SSTATE_DIR, etc). The default is the build tree which will not be
+  # persistent, so this should be set in the runner.
+  CACHE_DIR: $CI_PROJECT_DIR
   # The container mirror to use
   MIRROR_GHCR: ghcr.io
   # The list of extra Kas fragments to be used when building
--=20
2.43.0