Roles mangled by Membership service due to hardcoded LTI version

[chrispittman]

In two places in Service/Membership/getMembers(), Tool::parseRoles() is called, with a hardcoded LTI version of Util::LTI_VERSION2. This leads to a bug in LTI 1.3 tools, which can receive membership roles for a user such as this pair (for a user who is both a teacher and a TA in the same course):

  [ "http://purl.imsglobal.org/vocab/lis/v2/membership/Instructor#TeachingAssistant" , 
    "http://purl.imsglobal.org/vocab/lis/v2/membership#Instructor" ]

parseRoles() using LTI_VERSION2 incorrectly collapses these down into one role:

  http://purl.imsglobal.org/vocab/lis/v2/membership#TeachingAssistant

...which isn't even one of the roles that the LTI 1.3 spec allows, as far as I can tell.

Changing the hardcoded version in these calls to LTI_VERSION1P3 causes this pair of roles to be preserved correctly.

(Offhand, it looks like the Membership class has access to the platform's LTI version (through $this->source->getPlatform()->ltiVersion)...maybe it could use that instead of hardcoding LTI_VERSION2?)

[spvickers]

Thanks for reporting this, I will take a closer look. On first glance the first call to parseRoles in Service/Membership looks correct as it relates to a JSON-LD response, but the second may be wrong.

[spvickers]

Thanks again for reporting this,. You are quite correct, the LTI version passed to the parseRoles method should be the version to be used for the roles being returned. I have committed the change to fix this.