Description
If your plugin ci test started reporting the error similar to:
/home/travis/moodle/theme/mytheme/templates/header.mustache - WARNING: Problem calling HTML validator - please report bug to integration team.
for every mustache file in your plugin, you are in big trouble!
Haha, joking. Have a look at build system information at the top of Travis build log, it will be something like:
Build system information
Build language: php
Build group: stable
Build dist: xenial
This mean that Travis started using Ubuntu Xenial on VM, and this is where the problem is coming from.
Before getting into more details, here is a quick fix. Unless there is a specific reason you need Xenial, just pin Travis to use Ubuntu Trusty instead (in fact if the problem came out of blue, check system information on last successful CI run, I bet Trusty was used there) by adding this line to your .travis.yml:
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,3 +1,5 @@
+dist: trusty
+
language: php
sudo: required
OK, now more details on root cause. The issue is realated to version of java, validator used in moodle-local-ci and the way how validator output is handled in moodle-local-ci. Although, we requre openjdk-8-jre-headless package in .travis.yml, it apparently has no effect for Xenial, which comes with openjdk10 and openjdk11 installed. By default java there is referring to openjdk11:
travis@travis-job-d5d214f7-f40c-4cb6-8289-5bff56fde2e8:~/build/moodleworkplace/moodle-theme_workplace$ whereis java
java: /usr/bin/java /usr/share/java /usr/local/lib/jvm/openjdk11/bin/java /usr/share/man/man1/java.1.gz
We know that mustache linting works fine with openjdk8. But there is no obvious way of swithing java version to 8 as part of build, as update-alternatives does not see openjdk10 and 11 (they are not coming from apt packages):
travis@travis-job-d5d214f7-f40c-4cb6-8289-5bff56fde2e8:~/build/moodleworkplace/moodle-theme_workplace$ update-alternatives --config java
There is only one alternative in link group java (providing /usr/bin/java): /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
Nothing to configure.
This has been acknowleged by travis already, and if you need to run Xenial with openjdk8 for some reason, you may try adding this hack to your before_install script (did not test).
What is actually happening during linting is reported to moodle-local-ci maintainers (MDLSITE-5739).
I am not sure if this requires a PR for now, or we can keep this ticket open for reference and discussion.