Fix support for non-master default pack branches

If any packs end up using `main` instead of `master` as their default
branch, then deploying the index will fail without this change.

Currently only the `test` and `test2` packs use an non-master default
branch (`aaa`). So, the impact of this change is minimal.

Author: cognifloyd

.circle/deployment

@@ -21,6 +21,10 @@ fi
 # TODO: remove the install_gh call once circleci config is updated in all packs
 type gh &>/dev/null || ~/ci/.circle/install_gh
 
+# GH_TOKEN is used by gh which is used in functions.sh
+export GH_TOKEN=${MACHINE_PASSWORD}
+source ~/ci/tools/functions.sh
+
 # TODO: figure out how to make deploy.py rebuild the index.
 # python ~/packs/.circle/deploy.py pack.yaml "${CIRCLE_PROJECT_REPONAME}"
 
@@ -54,10 +58,11 @@ do
   fi
 done
 
+DEFAULT_BRANCH=$(_gh_default_branch)
 # Afer pushing the version, make sure we check out the latest commit
 # This is important so index reflects latest changes
-git checkout master
-git reset --hard master
+git checkout ${DEFAULT_BRANCH}
+git reset --hard ${DEFAULT_BRANCH}
 
 # Verify there are no unstaged changes
 git status

tools/functions.sh

@@ -0,0 +1,13 @@
+#### gh helpers
+
+_gh_default_branch() {
+    # get the default branch for the current repo (might not be master)
+
+    gh api graphql -F owner=':owner' -F name=':repo' -f query='
+      query($name: String!, $owner: String!) {
+        repository(owner: $owner, name: $name) {
+          defaultBranchRef { name }
+        }
+      }
+    ' | jq -r '.data.repository.defaultBranchRef.name'
+}