[setup topic/libsolv] Crash after incomplete download

[Ken Brown]

On 11/7/2017 1:15 PM, Jon Turney wrote:
> On 02/11/2017 19:25, Ken Brown wrote:
>> On 11/2/2017 1:22 PM, Jon Turney wrote:
>>> On 01/11/2017 20:38, Ken Brown wrote:
>>>> If there is a download failure and the user clicks Yes in response 
>>>> to "Download Incomplete.  Try again?", then setup will crash.  The 
>>>> crash occurs at PickView.cc:447 because i->source() is NULL.
>>>
>>> Thanks for finding all these problems!
>>>
>>>> I haven't yet analyzed this in further detail, but the crux of the 
>>>> issue seems to be that we call do_ini_thread a second time without 
>>>> having cleaned out the package database and the libsolv pool.
>>>>
>>>> This is probably a symptom of a more general problem, which is that 
>>>> we haven't thought carefully (or at least I haven't) about what 
>>>> happens when we visit certain pages for a second time, after the 
>>>> libsolv pool has been created.
>>>
>>> The fact that this isn't considered at all at the moment makes me 
>>> wonder if it's working correctly in this situation currently.  But, 
>>> yeah, I agree that packagedb state should be cleared in this case.
>>>
>>> I tried with the attached, but it still segfaults at the same place.
>>>
>>> This seems to be because all the packagedb prep (including 
>>> fixup_source_package_ids) is in OnInit() (which is only called once 
>>> per page, but lazily), rather than OnActivate(), so probably some 
>>> more restructuring is needed there :(
>>
>> I guess we could move all that prep to OnActivate() but make sure it's 
>> only run when we've gotten to the chooser page from the site page (and 
>> not because the user pressed Back on the prereq page).  What about 
>> adding a 'prepped' data member to packagedb and using this to decide 
>> whether to run the prep code?
> 
> An attempt at this to follow, but this ended up touching rather more 
> stuff than I wanted to, so I'm sure something else has broken :(

Well, at least the crash is gone.

Ken