Travis CI: Update config from rabbitmq-common

Author: dumbbell

.travis.yml

@@ -1,8 +1,8 @@
 # vim:sw=2:et:
 
+os: linux
 dist: xenial
-sudo: false
-language: erlang
+language: elixir
 notifications:
   email:
     recipients:
@@ -20,26 +20,31 @@ env:
     - secure: E4FIneR14YxnWbNNgFY48+Z8YpnwWcvIR0nD1Mo06WKXaq05UfQNQ7SZCjI3kKCNJGMhac12DFRhln+mQZ+T92MQ7IeU3ugpV5RSm+JqIwwIKzVM3+bjCQnFoL24OD4E+GjhJQWYQmPyM7l4OPluMr2N8BtANItgzX3AvljvlSc=
     - secure: L1t0CHGR4RzOXwtkpM6feRKax95rszScBLqzjstEiMPkhjTsYTlAecnNxx6lTrGMnk5hQoi4PtbhmyZOX0siHTngTogoA/Nyn8etYzicU5ZO+qmBQOYpegz51lEu70ewXgkhEHzk9DtEPxfYviH9WiILrdUVRXXgZpoXq13p1QA=
 
+    # $base_rmq_ref is used by rabbitmq-components.mk to select the
+    # appropriate branch for dependencies.
+    - base_rmq_ref=v3.8.x
+
+elixir:
+  - '1.9'
 otp_release:
-  - "21.3"
-
-before_script:
-  - elixir --version
-  # The checkout made by Travis is a "detached HEAD" and branches
-  # information is missing. Our Erlang.mk's git_rmq fetch method relies
-  # on it, so we need to restore it.
-  #
-  # We simply fetch master and, if it exists, v3.8.x branches. A branch
-  # is created, pointing to the detached HEAD.
-  - |
-    git checkout -B "${TRAVIS_TAG:-${TRAVIS_BRANCH}}"
-    git remote add upstream https://github.com/$TRAVIS_REPO_SLUG.git
-    git fetch upstream v3.8.x:v3.8.x || :
-    git fetch upstream master:master || :
+  - '21.3'
+  - '22.2'
+
+install:
+  # This project being an Erlang one (we just set language to Elixir
+  # to ensure it is installed), we don't want Travis to run mix(1)
+  # automatically as it will break.
+  skip
 
 script:
+  # $current_rmq_ref is also used by rabbitmq-components.mk to select
+  # the appropriate branch for dependencies.
+  - make check-rabbitmq-components.mk
+    current_rmq_ref="${TRAVIS_PULL_REQUEST_BRANCH:-${TRAVIS_BRANCH}}"
   - make xref
+    current_rmq_ref="${TRAVIS_PULL_REQUEST_BRANCH:-${TRAVIS_BRANCH}}"
   - make ct-fast
+    current_rmq_ref="${TRAVIS_PULL_REQUEST_BRANCH:-${TRAVIS_BRANCH}}"
 
 after_failure:
   - |