Teach 'tar' to support more file types

Teach 'tar' to support more file types

[Eitan Adler]

commit 61dba0a47a6a923a777c3a4c115af357ccf90396
Author: Eitan Adler <lists@eitanadler.com>
Date:   Sun Apr 1 18:06:56 2018 -0400

    Teach 'tar' to support more file types

    In libarchive based (BSD) tar implementations, all file types can be
    uncompressed, even without a filetype letter.  In GNU tar's case
    "recent" versions (for over 10 years) can do the same.
    As such, remove the check for tar type and just assume it works.

diff --git a/Completion/Unix/Type/_tar_archive
b/Completion/Unix/Type/_tar_archive
index 28df77638..8e8c45b12 100644
--- a/Completion/Unix/Type/_tar_archive
+++ b/Completion/Unix/Type/_tar_archive
@@ -20,10 +20,8 @@ if [[ "$1" = *[urtx]* ]]; then
     _files "$expl[@]" -g '*.(tar|TAR).bz2(-.)'
   elif [[ "$1" = *J* ]]; then
     _files "$expl[@]" -g '*.(tar|TAR).(lzma|xz)(-.)'
-  elif [[ "$_cmd_variant[$service]" == gnu ]]; then
-    _files "$expl[@]" -g
'*.((tar|TAR)(.gz|.GZ|.Z|.bz2|.lzma|.xz|)|(tbz|tgz|txz))(-.)'
   else
-    _files "$expl[@]" -g '*.(tar|TAR)(-.)'
+    _files "$expl[@]" -g
'*.((tar|TAR)(.gz|.GZ|.Z|.bz2|.lzma|.xz|)|(tbz|tgz|txz))(-.)'
   fi
 else
   _files "$expl[@]"


-- 
Eitan Adler

Re: Teach 'tar' to support more file types

[Jun T]

> 2018/04/02 7:10, Eitan Adler <lists@eitanadler.com> wrote:
> 
>    In libarchive based (BSD) tar implementations, all file types can be
>    uncompressed, even without a filetype letter.  In GNU tar's case
>    "recent" versions (for over 10 years) can do the same.
>    As such, remove the check for tar type and just assume it works.

We can't assume it works since there are many systems where tar requires
explicit compression flags. Even on some BSDs (OpenBSD and NetBSD) tar
is not based on libarchive.

If the tar command is based on libarchive, we can detect it by using
'tar --version'.


diff --git a/Completion/Unix/Command/_tar b/Completion/Unix/Command/_tar
index cff50562e..3e44b98f7 100644
--- a/Completion/Unix/Command/_tar
+++ b/Completion/Unix/Command/_tar
@@ -21,7 +21,7 @@ local _tar_cmd tf tmp tmpb del index
 # from some of the possible long options, and from the second word if
 # that does not start with a hyphen.
 
-if _pick_variant gnu=GNU unix --version; then
+if _pick_variant gnu=GNU libarchive=libarchive unix --version; then
   case "$($service --version)" in
     ("tar (GNU tar) "(#b)([0-9.-]##)*)
     autoload -z is-at-least
diff --git a/Completion/Unix/Type/_tar_archive b/Completion/Unix/Type/_tar_archive
index 28df77638..e8ddb1e59 100644
--- a/Completion/Unix/Type/_tar_archive
+++ b/Completion/Unix/Type/_tar_archive
@@ -20,7 +20,7 @@ if [[ "$1" = *[urtx]* ]]; then
     _files "$expl[@]" -g '*.(tar|TAR).bz2(-.)'
   elif [[ "$1" = *J* ]]; then
     _files "$expl[@]" -g '*.(tar|TAR).(lzma|xz)(-.)'
-  elif [[ "$_cmd_variant[$service]" == gnu ]]; then
+  elif [[ "$_cmd_variant[$service]" == (gnu|libarchive) ]]; then
     _files "$expl[@]" -g '*.((tar|TAR)(.gz|.GZ|.Z|.bz2|.lzma|.xz|)|(tbz|tgz|txz))(-.)'
   else
     _files "$expl[@]" -g '*.(tar|TAR)(-.)'

Re: Teach 'tar' to support more file types

[Baptiste Daroussin]

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On Thu, Apr 05, 2018 at 12:55:21PM +0900, Jun T wrote:
> 
> > 2018/04/02 7:10, Eitan Adler <lists@eitanadler.com> wrote:
> > 
> >    In libarchive based (BSD) tar implementations, all file types can be
> >    uncompressed, even without a filetype letter.  In GNU tar's case
> >    "recent" versions (for over 10 years) can do the same.
> >    As such, remove the check for tar type and just assume it works.
> 
> We can't assume it works since there are many systems where tar requires
> explicit compression flags. Even on some BSDs (OpenBSD and NetBSD) tar
> is not based on libarchive.
> 
> If the tar command is based on libarchive, we can detect it by using
> 'tar --version'.
> 
bsdtar 3.3.2 - libarchive 3.3.2 zlib/1.2.11 liblzma/5.2.3 bz2lib/1.0.6

yes :)

Bapt

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Re: Teach 'tar' to support more file types

[Eitan Adler]

On 4 April 2018 at 20:55, Jun T <takimoto-j@kba.biglobe.ne.jp> wrote:
>
>> 2018/04/02 7:10, Eitan Adler <lists@eitanadler.com> wrote:
>>
>>    In libarchive based (BSD) tar implementations, all file types can be
>>    uncompressed, even without a filetype letter.  In GNU tar's case
>>    "recent" versions (for over 10 years) can do the same.
>>    As such, remove the check for tar type and just assume it works.
>
> We can't assume it works since there are many systems where tar requires
> explicit compression flags. Even on some BSDs (OpenBSD and NetBSD) tar
> is not based on libarchive.
>
> If the tar command is based on libarchive, we can detect it by using
> 'tar --version'.

This patch LGTM.


-- 
Eitan Adler