Query not assigning to variable

Question

I am having an issue where I am running a query in a trigger to search for a ProcessInstance record. In my debug, the query returns a record and values. However, when I try to assign that query result to a ProcessInstance variable or add it to a ProcessInstance list, it fails.

try{
    for(ProcessInstance p: [SELECT CompletedDate,CreatedById,CreatedDate,ElapsedTimeInDays,ElapsedTimeInHours,ElapsedTimeInMinutes,Id,IsDeleted,LastActorId,LastModifiedById,LastModifiedDate,ProcessDefinitionId,Status,SubmittedById,SystemModstamp,TargetObjectId FROM ProcessInstance WHERE TargetObjectId = :AR.id  AND Status = 'Pending' LIMIT 1]){
         PIlist.add(p);
         system.debug('PIlist.size() = ' + PIlist.size());
         }
         PIlist = [SELECT CompletedDate,CreatedById,CreatedDate,ElapsedTimeInDays,ElapsedTimeInHours,ElapsedTimeInMinutes,Id,IsDeleted,LastActorId,LastModifiedById,LastModifiedDate,ProcessDefinitionId,Status,SubmittedById,SystemModstamp,TargetObjectId FROM ProcessInstance WHERE TargetObjectId = :AR.id  AND Status = 'Pending' LIMIT 1];
         PI=[SELECT CompletedDate,CreatedById,CreatedDate,ElapsedTimeInDays,ElapsedTimeInHours,ElapsedTimeInMinutes,Id,IsDeleted,LastActorId,LastModifiedById,LastModifiedDate,ProcessDefinitionId,Status,SubmittedById,SystemModstamp,TargetObjectId FROM ProcessInstance WHERE TargetObjectId = :AR.id  AND Status = 'Pending' LIMIT 1];
                }
      catch(Exception e){
           system.debug('No ProcesssInstance.  AR.Id=' + AR.id + '    Heres the query:' + [SELECT CompletedDate,CreatedById,CreatedDate,ElapsedTimeInDays,ElapsedTimeInHours,ElapsedTimeInMinutes,Id,IsDeleted,LastActorId,LastModifiedById,LastModifiedDate,ProcessDefinitionId,Status,SubmittedById,SystemModstamp,TargetObjectId FROM ProcessInstance WHERE TargetObjectId = :AR.id]);
                }   

The debug returns:

10:56:21:180 USER_DEBUG [21]|DEBUG|No ProcesssInstance. AR.Id=a1QR0000002zuy8MAA Heres the query:(ProcessInstance:{CreatedById=005o0000000Ip8lAAC, CreatedDate=2016-05-11 17:56:21, ElapsedTimeInDays=0.000, ElapsedTimeInHours=0.00, ElapsedTimeInMinutes=0, Id=04gR0000000JEOnIAO, IsDeleted=false, LastModifiedById=005o0000000Ip8lAAC, LastModifiedDate=2016-05-11 17:56:21, ProcessDefinitionId=04aR00000008TsmIAE, Status=Started, SubmittedById=005o0000000Ip8lAAC, SystemModstamp=2016-05-11 17:56:21, TargetObjectId=a1QR0000002zuy8MAA})"

Any idea why this would be happening?

Answer 1

According to your debug the ProcessInstance status is "started"

ProcessInstance:{CreatedById=005o0000000Ip8lAAC, CreatedDate=2016-05-11 17:56:21, ElapsedTimeInDays=0.000, ElapsedTimeInHours=0.00, ElapsedTimeInMinutes=0, Id=04gR0000000JEOnIAO, IsDeleted=false, LastModifiedById=005o0000000Ip8lAAC, LastModifiedDate=2016-05-11 17:56:21, ProcessDefinitionId=04aR00000008TsmIAE, Status=Started, SubmittedById=005o0000000Ip8lAAC, SystemModstamp=2016-05-11 17:56:21, TargetObjectId=a1QR0000002zuy8MAA}

However in all of your queries except the last one you have status filtered to 'Pending'. Therefore you will never return the ProcessInstance. You need to remove the Status = 'Pending' filter from your WHERE clause