NPE in FeedbackContributionQuestionDetails.getTeamSubmissionArray

[damithc]

v6.16.2

I've been getting this error from the live server. There was a handful of it, reported in two day so far.

Error Message: teammates.common.util.Logger severe: Unexpected exception caught by ControllerServlet :
java.lang.NullPointerException
at teammates.common.datatransfer.questions.FeedbackContributionQuestionDetails.getTeamSubmissionArray(FeedbackContributionQuestionDetails.java:517)
at teammates.common.datatransfer.questions.FeedbackContributionQuestionDetails.getQuestionResultStatisticsCsv(FeedbackContributionQuestionDetails.java:342)
at teammates.logic.core.FeedbackSessionsLogic.getFeedbackSessionResultsForQuestionInCsvFormat(FeedbackSessionsLogic.java:822)
at teammates.logic.core.FeedbackSessionsLogic.getFeedbackSessionResultsSummaryInSectionAsCsv(FeedbackSessionsLogic.java:800)
at teammates.logic.core.FeedbackSessionsLogic.getFeedbackSessionResultsSummaryAsCsv(FeedbackSessionsLogic.java:745)
at teammates.logic.api.Logic.getFeedbackSessionResultSummaryAsCsv(Logic.java:1243)
at teammates.ui.controller.InstructorFeedbackResultsDownloadAction.execute(InstructorFeedbackResultsDownloadAction.java:58)
at teammates.ui.controller.Action.executeAndPostProcess(Action.java:478)
at teammates.ui.controller.ControllerServlet.doPost(ControllerServlet.java:75)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)

[damithc]

actually, a user is unable to download results due to this problem. An urgent fix is needed.

[damithc]

Note that the course in concern has some unusual team names:

5 and alive
5 and alive
5 and alive
5 and alive
99 Problems But Stats A'int One
99 Problems But Stats A'int One
99 Problems But Stats A'int One
99 Problems But Stats A'int One
Above Average
Above Average
Above Average
Above Average
Algebros
Algebros
Algebros
Algebros
BleedBlue
BleedBlue
BleedBlue
BleedBlue
CamFam
CamFam
CamFam
CamFam
Coding Crazies
Coding Crazies
Coding Crazies
Coding Crazies
Confounding Variables
Confounding Variables
Confounding Variables
Confounding Variables
Correlation is Causation
Correlation is Causation
Correlation is Causation
Correlation is Causation
Dream Team
Dream Team
Dream Team
Dream Team
Duke Stat Kidz
Duke Stat Kidz
Duke Stat Kidz
Duke Stat Kidz
Exclusive Sheep
Exclusive Sheep
Exclusive Sheep
FantasticFour
FantasticFour
FantasticFour
FantasticFour
Fantstic-4
Fantstic-4
Fantstic-4
Fantstic-4
Girls Who Code
Girls Who Code
Girls Who Code
Girls Who Code
Juniors
Juniors
Juniors
Juniors
MEAN Girls
MEAN Girls
MEAN Girls
MEAN Girls
MegaCalculator
MegaCalculator
MegaCalculator
MegaCalculator
Outliers
Outliers
Outliers
Outliers
R-mageddon
R-mageddon
R-mageddon
R-mageddon
Red Team
Red Team
Red Team
Red Team
Spaghetti Carbonara
Spaghetti Carbonara
Spaghetti Carbonara
Spaghetti Carbonara
Standard Deviants
Standard Deviants
Standard Deviants
Standard Deviants
Stat Seniors
Stat Seniors
Stat Seniors
Stat Seniors
aRmy
aRmy
aRmy
aRmy
Stat-tastic
Stat-tastic
Stat-tastic
Stat-tastic
Team Mean
Team Mean
Team Mean
Team Mean
Team Super Stat
Team Super Stat
Team Super Stat
Team Super Stat
Team dos
Team dos
Team dos
Team dos
TeamEnigma
TeamEnigma
TeamEnigma
TeamEnigma
The Outliers
The Outliers
The Outliers
The Outliers
The Whiskers
The Whiskers
The Whiskers
The Whiskers
TrueMean
TrueMean
TrueMean
TrueMean
Washed Up
Washed Up
Washed Up
Washed Up
We dont like 8:30's
We dont like 8:30's
We dont like 8:30's
We dont like 8:30's
Zoe 101
Zoe 101
Zoe 101
Zoe 101
Instructors
Instructors
Instructors

[xpdavid]

Fixed the issue with @damithc by changing teamName Instructors to something else. The error can be reproduced by enrolling students with teamName Instructors.

Instructors is internally used in the application as a team for instructors.

Ideally, teamName can be anything so disallowing Instructors is not a good choice. Need to investigate some other approaches.

[Ali96kz]

@damithc What about making teammates.common.util.Const#USER_TEAM_FOR_INSTRUCTOR more unique? Something like INSTRUCTORS_TEAMMATES_VAR

[xpdavid]

It works but not the optimal. (e.g. what if a team is called INSTRUCTORS_TEAMMATES_VAR?). I think the issue is more challenging than you think as this requires data migration if we want to make changes. If you are new to teammates, please find some firstTimer task to tackle :P