fix(packaging): slack notifications and DRA branch for PRs (#19188) (#19204)

Author: mergify[bot]

.buildkite/hooks/post-checkout

@@ -10,6 +10,12 @@
 
 set -eo pipefail
 
+# Upload should not do much with the pre-command.
+if [[ "$BUILDKITE_COMMAND" =~ .*"upload".* ]]; then
+  echo "Skipped pre-command when running the Upload pipeline"
+  exit 0
+fi
+
 # shellcheck disable=SC1091
 source .buildkite/scripts/utils.sh
 

.buildkite/hooks/pre-command

@@ -1,8 +1,8 @@
 notify:
   - slack: "#apm-server"
-    if: build.state == "failed"
+    if: build.state == "failed" && build.branch =~ /^(main|\d+\.\d+|\d+\.x)$$/
   - slack: "#observablt-bots"
-    if: "build.state != 'passed'"
+    if: build.state == "failed" && build.branch =~ /^(main|\d+\.\d+|\d+\.x)$$/
 
 env:
   IMAGE_UBUNTU_X86_64: "family/core-ubuntu-2404"

.buildkite/package.yml

@@ -32,7 +32,8 @@ retry() {
 
 #
 # An opinionated approach to detect if unsupported Unified Release branches
-# can be used, this is handy for testing feature branches in dry-run mode
+# can be used, this is handy for testing feature branches in dry-run mode.
+# In addition support for PRs is added by using the base branch of the PR.
 # It produces the below environment variables:
 # - VERSION
 # - DRA_COMMAND
@@ -58,6 +59,9 @@ dra_process_other_branches() {
         buildkite-agent annotate "It was not possible to know the original base branch for ${BUILDKITE_BRANCH}. This won't fail - this is a feature branch." --style 'info' --context 'ctx-info-feature-branch'
       fi
     fi
+  elif [[ -n "$BUILDKITE_PULL_REQUEST_BASE_BRANCH" ]]; then
+    DRA_BRANCH="$BUILDKITE_PULL_REQUEST_BASE_BRANCH"
+    DRA_COMMAND=list
   fi
   export DRA_BRANCH DRA_COMMAND VERSION
 }