Re: problem using jgit

[Marek Zawirski <marek.zawirski@gmail.com>]

Marek Zawirski wrote:
> Stephen Bannasch wrote:
>> I've setup a simple test class that integrates jgit to clone a git 
>> repository. However I'm getting a NullPointerError when 
>> RevWalk.parseAny ends up producing a null object id.
>>
>> The code and the stack trace for the error are here:
>>
>>   http://pastie.org/237711
>>
>> This problem occurs using the jgit from the master branch from this 
>> repo:
>>
>>   git://repo.or.cz/egit.git
> Hello Stephen,
>
> I think you've experienced error caused by the same bug as me, during 
> my latest fetch/push GUI works few days ago.
> Your code looks fine, probably  it's actually bug in jgit. I think 
> it's some regression. Thanks for reporting.
It's caused by 14a630c3: Cached modification times for symbolic refs too
Changes introduced by this patch made Repository#getAllRefs() including 
Ref objects with null ObjectId in case of unresolvable (invalid?) HEAD 
symbolic ref, and null Ref for HEAD  when it doesn't exist. Previous 
behavior was just not including such refs in result.

Fix for null Ref is just a matter of simple filtering out null Ref 
object for HEAD, if it doesn't exist (just is it considered to be legal 
state of repository when HEAD doesn't exist?).

To fix null ObjectId issue, we have to either change all clients of this 
method or revert method to previous behavior. Now it's just unspecified 
in javadoc.
Robin, Shawn, what do you think? If we want to have unresolvable refs 
included, IMO it may be sensible to provide argument includeUnresolbable 
for Repository#getAllRefs() to let clients avoid burden of filtering 
them out when they don't need them (most cases, perhaps).
I can prepare fix for it (rather easy one) as you are unavailable now, 
let me now what's your opinion.