Re: [bug] Reliably Reproducible Bad Packing of Objects

From: Duy Nguyen <pclouds@gmail.com>
Date: Jul 2, 2016, 14:35 UTC
Message-ID: <CACsJy8AJxbnEXciP91_r0jtH3mv+T_dqQZt9pKnJvSK-s9Yamg@mail.gmail.com>
In-Reply-To: <20160702091034.GA31852@duynguyen>

On Sat, Jul 2, 2016 at 11:10 AM, Duy Nguyen <pclouds@gmail.com> wrote:

Show 21 quoted lines

> On Sat, Jun 25, 2016 at 12:38:22AM +0200, Christoph Michelbach wrote:
>> Hi,
>>
>> when run on a 32 bit system (Linux system, don't know about other
>> systems),
>>
>> mkdir test && cd test && git init && touch someFile && git add someFile
>> && git commit -m "Initial commit." && dd if=/dev/urandom
>> of=bigBinaryFile bs=1MB count=4294 && git add bigBinaryFile && git
>> commit -m "Introduced big biary file."
>>
>> reliably produces this error message: "error: bad packed object CRC
>> for"
>
>
> I tried with a 32-bit git build on 64-bit system and did not see this
> message. Maybe it's because the 64-bit system. Just too lazy to bring
> up a 32-bit VM to process 4GB of data.
>
> But I did look around a bit, and the problem is probably number
> truncation. Could you try this patch?

Just FYI. There may be more truncation problems on 32-bit systems. "clang -Wshorten-64-to-32" reports a couple of spots that could be real problems (pack-objects, index-pack...) for handling 4+ GB files on these systems. Still working on it...

-- 
Duy