On the state of 'tar'

[hasufell]

The problem with libarchive and bindings in general is portability.

A half way out of this would be to allow cabal/ghc to do partially
static linking. But that's probably not gonna happen anytime soon.

Alternatively... have a +static cabal flag that builds from bundled
source? Ideas...

But I think a native 'tar' implementation is still worthwhile.


On 07/04/2020 21:35, Vanessa McHale wrote:
> FWIW, the tar format is a mess, which is part of why I chose to bind to
> libarchive (with all the difficulties) instead of writing my own
> library. There’s a nice post
> here: https://www.cyphar.com/blog/post/20190121-ociv2-images-i-tar
> 
> There’s also archive-sig
> (http://hackage.haskell.org/package/archive-sig) which tries to be a
> “common interface” via backpack and has implementations such as
> archive-tar-bytestring
> (http://hackage.haskell.org/package/archive-tar-bytestring) that can be
> swapped out with libarchive/tar proper so you don’t need to commit to
> any one library. 
> 
> Cheers,
> Vanessa McHale
> 
>> On Apr 7, 2020, at 11:50 AM, hasufell <hasufell at posteo.de
>> <mailto:hasufell at posteo.de>> wrote:
>>
>> Friends,
>>
>> 'tar' [0][1] is an excellent native haskell implementation of the tar
>> format. However, there are currently a lot of unattended issues:
>>
>> * unicode filepaths broken due to Char8 use [2]
>> * executable bits handled improperly [3]
>> * no support for long filepath extension [4][5]
>> * doesn't handle hardlinks properly [6]
>> * handles symbolic links too strictly [7]
>>
>> Most of these issues are 2 to 4 years old, some of them have PRs that
>> have never been reviewed.
>>
>> 'tar' fails to unpack our own ghc bindists even [4]. I consider it, in
>> this state, too unreliable for production use. Since it is in the
>> 'haskell' namespace on github and probably the first hit on hackage,
>> this needs to be improved quickly, IMO.
>>
>> Users currently can use tar-bytestring [8] (no windows support) or
>> libarchive [9] (not a native implementation), but 'tar' should
>> ultimately be fixed and maintained properly.
>>
>> --
>> [0] https://hackage.haskell.org/package/tar
>> [1] https://github.com/haskell/tar
>> [2] https://github.com/haskell/tar/issues/6
>> [3] https://github.com/haskell/tar/issues/25
>> [4] https://github.com/haskell/tar/issues/49
>> [5] https://github.com/haskell/tar/issues/27
>> [6] https://github.com/haskell/tar/issues/51
>> [7] https://github.com/haskell/tar/issues/32
>> [8] https://github.com/hasufell/tar-bytestring
>> [9] https://hackage.haskell.org/package/libarchive
>> --
>>
>>
>> Cheers,
>> Julian
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