Bug#1065751: Incomplete fix for xz -T1

[Jia Tan]

Hello!

I took a look at the patch and attached a small patch fix for it.
I hope this helps!

Jia Tan
From 0f03dce25f174725e80dcd78bfa6ddd640b3714a Mon Sep 17 00:00:00 2001
From: Jia Tan 
Date: Sun, 10 Mar 2024 22:16:20 +0800
Subject: [PATCH] pristine-xz: Fix -T1 fallback if threads not specified.

---
 pristine-xz | 16 
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/pristine-xz b/pristine-xz
index 2046578..f3a8eab 100755
--- a/pristine-xz
+++ b/pristine-xz
@@ -403,7 +403,14 @@ sub genxz {
   }
 
   my @params = split(' ', $delta->{params});
+
+  # Flag indicating if the threads were set in the params file. If
+  # the threads were not set, then default back to single threaded
+  # mode. This is necessary for backwards compatibility with .xz files
+  # created before XZ Utils 5.6.0, when the default threading mode was
+  # changed to multi-threading (which produces different output).
   my $threads_set = 0;
+
   while (@params) {
 my $param = shift @params;
 
@@ -416,11 +423,12 @@ sub genxz {
   next if $param eq '--check=crc64';
   next if $param eq '--check=sha256';
   next if $param =~ /^(--block-list=[0-9,]+)$/;
-  next if $param =~ /^-T[0-9]+$/;
+
+  # Set $threads_set before checking next argument.
   if ($param =~ /^-T[0-9]+$/) {
-			$threads_set = 1;
-			next;
-		}
+$threads_set = 1;
+next;
+  }
 } elsif ($delta->{program} eq 'pixz') {
   next if $param eq '-t';
 }
-- 
2.34.1

Bug#1065751: Incomplete fix for xz -T1

[Jeremy Bícha]

This issue also affects being able to use git-buildpackage to generate
pristine-tar tarballs for tarballs that were already committed before
the recent changes to pristine-tar. For instance I experienced it
today with `gbp buildpackage` with gtk4 but the original tarball was
committed in January.

Ideally, we would not need to attempt to reconstruct old pristine-tar
git branches since that sounds like a very large amount of work and
it's disruptive to everyone who has local copies of the git repos.

Thank you,
Jeremy Bícha

Bug#1065751: Incomplete fix for xz -T1

[Andrey Rakhmatullin]

On Sun, Mar 10, 2024 at 12:34:00AM +0500, Andrey Rahmatullin wrote:
> It looks like #1063252 was not enough to support tar.xz files created by new
> xz-utils. I've created a tarball, committed it into my gbp repo, checked it 
> out
> and xz -lvv doesn't show the cu flags for it (and so it's not identical to the
> original one). 
A workaround for this is to reset the pristine-tar branch, deleting the
committed cu flags tarball and commit the -- flags one (that you just
checked out) manually.


-- 
WBR, wRAR


signature.asc
Description: PGP signature

Bug#1065751: Incomplete fix for xz -T1

[Andrey Rahmatullin]

Package: pristine-tar
Version: 1.50+nmu1
Severity: serious
X-Debbugs-Cc: Sebastian Andrzej Siewior 

It looks like #1063252 was not enough to support tar.xz files created by new
xz-utils. I've created a tarball, committed it into my gbp repo, checked it out
and xz -lvv doesn't show the cu flags for it (and so it's not identical to the
original one). As making a minimal example involving git sounds too complicated
I tried to make a minimal example with raw commands, hopefully I did that
correctly:

$ mkdir 1
$ echo foo > 1/bar
$ tar cJf 1.tar.xz 1
$ xz -lvv 1.tar.xz
[...]
Flags
cu
[...]
$ pristine-tar gendelta 1.tar.xz 1.tar.xz.delta

$ cd 1
$ pristine-tar gentar ../1.tar.xz.delta ../2.tar.xz
$ xz -lvv ../2.tar.xz
[...]
Flags
--
[...]


-- System Information:
Debian Release: trixie/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'testing-debug'), (500, 
'unstable'), (500, 'testing'), (101, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 6.7.7-amd64 (SMP w/4 CPU threads; PREEMPT)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, 
TAINT_UNSIGNED_MODULE
Locale: LANG=ru_RU.UTF-8, LC_CTYPE=ru_RU.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages pristine-tar depends on:
ii  bzip21.0.8-5+b2
ii  libbz2-1.0   1.0.8-5+b2
ii  libc62.37-15.1
ii  libsys-cpuaffinity-perl  1.13~03-2+b3
ii  pbzip2   1.1.13-1
ii  perl 5.38.2-3.2
ii  pixz 1.0.7-2
ii  tar  1.35+dfsg-3
ii  xdelta   1.1.3-10.6
ii  xdelta3  3.0.11-dfsg-1.2
ii  xz-utils 5.6.0-0.2
ii  zlib1g   1:1.3.dfsg-3.1

pristine-tar recommends no packages.

pristine-tar suggests no packages.

-- debconf-show failed