[...]

state without impacting any branches by performing another checkout.
If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:
  git checkout -b new_branch_name
HEAD is now at a48d202... - up to 1.4.8
fatal: HEAD does not point to a branch
Available branches: AC-branch RA-branch master
Searching for tag auto/ti/libmatroska-1.4.8-1...
Searching for tag auto/ti/libmatroska-1_4_8-1...
--2018-03-13 10:31:38--  http://distfiles.pld-linux.org/distfiles/by-md5/4/5/45ffda84badb4e3da5d8f2535e54d511/libmatroska-1.4.8.tar.xz
Resolving distfiles.pld-linux.org (distfiles.pld-linux.org)... 193.239.45.41
Connecting to distfiles.pld-linux.org (distfiles.pld-linux.org)|193.239.45.41|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 286284 (280K) [application/octet-stream]
Saving to: 'libmatroska-1.4.8.tar.xz'
     0K .......... .......... .......... .......... .......... 17% 1.20M 0s
    50K .......... .......... .......... .......... .......... 35% 2.40M 0s
   100K .......... .......... .......... .......... .......... 53% 64.4M 0s
   150K .......... .......... .......... .......... .......... 71%  195M 0s
   200K .......... .......... .......... .......... .......... 89% 2.45M 0s
   250K .......... .......... .........                       100%  130M=0.08s
2018-03-13 10:31:38 (3.32 MB/s) - 'libmatroska-1.4.8.tar.xz' saved [286284/286284]
Building target platforms: i686-linux
Wrote: /home/users/builder/rpm/SRPMS/libmatroska-1.4.8-1.src.rpm
exit status 0
Tagging with prefix: auto/ti/
HEAD is now at a48d202... - up to 1.4.8
fatal: HEAD does not point to a branch
Writing git revision for tag auto/ti/libmatroska-1.4.8-1
On detached HEAD. Use -r BRANCHNAME to override
error: Macro %_builddir has empty body
error: Macro %_builddir has empty body
Executing(--clean): env -i TMP=/home/users/builder/tmp HOME=/home/users/builder PATH=/bin:/usr/bin:/usr/sbin:/sbin:/usr/X11R6/bin TMPDIR=/home/users/builder/tmp  /bin/sh -e /home/users/builder/tmp/rpm-tmp.92347
+ umask 022
+ cd /home/users/builder/rpm/BUILD
+ rm -rf libmatroska-1.4.8
Begin-TLD-Builder-Info
Build-Time: user:0.92s sys:0.27s real:2.23s (faults io:0 non-io:88397)
Files queued for ftp:
    292623 libmatroska-1.4.8-1.src.rpm
       189 libmatroska-1.4.8-1.src.rpm.uploadinfo
End-TLD-Builder-Info