Trying to debug Travis CI

Author: mdupont

.travis.yml

@@ -1,6 +1,6 @@
 language: php
 
-dist: precise
+dist: xenial
 
 php:
     - 5.3
@@ -14,14 +14,21 @@ php:
 
 matrix:
     include:
+        - php: 5.4
+          dist: trusty  # force ubuntu 14.04, ubuntu >= 16.04 only has php >= 5.6
+        - php: 5.5
+          dist: trusty  # force ubuntu 14.04, ubuntu >= 16.04 only has php >= 5.6
         - php: 7.0
           env: COVERAGE=1
         - php: 5.3
-          env: COMPOSER_MEMORY_LIMIT=2G
+          dist: precise  # force ubuntu 12.04, ubuntu >= 14.04 only has php >= 5.4
+          env: COMPOSER_MEMORY_LIMIT=3G
         - php: 7.3
           env: DEPENDENCIES="--ignore-platform-reqs"
     exclude:
         - php: 5.3
+        - php: 5.4
+        - php: 5.5
         - php: 7.0
         - php: 7.3
 
@@ -36,6 +43,7 @@ env:
 
 before_install:
     ## Packages
+    - sudo rm -f /etc/apt/sources.list.d/mongodb.list  # Makes apt crash on Precise, and we don't need MongoDB
     - sudo apt-get update -qq
     - sudo apt-get install -y graphviz