RPM: Macros and SPEC to detect "from/to" package version in scriptlet

README.md

RPM %trigger* is broken:

• %triggerin -- %{name} < %{version}-%{release} is always triggered on upgrade · Issue #209 · rpm-software-management/rpm
  rpm-software-management/rpm#209

test.spec

%pre
if %{ver_cmp_opposite < 1.2.3-222.new}; then
  echo "Upgrade from $(%{ver_opposite}) (< 1.2.3-222.new)"
fi
exit 0

%postun
if %{ver_cmp_opposite < 1.2.3-222.new}; then
  echo "Downgrade to $(%{ver_opposite}) (< 1.2.3-222.new)"
fi
exit 0

ver_cmp.rpmmacros

## In %pre, %post of the installing package on upgrade or downgrade:
##   Print version string of the uninstalling package
## In %preun, %postun of the uninstalling package on upgrade or downgrade:
##   Print version string of the installing package
%ver_opposite(n:) \
LC_ALL=C \\\
rpm \\\
  -q \\\
  --queryformat '%%|epoch?{%%{epoch}:}|%%{version}-%%{release}\\n' \\\
  %{!-n:%{name}}%{-n*} \\\
|fgrep -v '%{?epoch:%{epoch}:}%{version}-%{release}' \\\
|grep -v ' is not installed$' \\\
|| :

## Compare 2 version strings with an operator
%ver_cmp() \
%{__python} -c '\
from __future__ import print_function\
import sys\
import rpm\
\
\
def stringToEVR(verstring):\
    i = verstring.find(":")\
    if i == -1:\
        epoch = None\
    else:\
        epoch = verstring[:i]\
    i += 1\
    j = verstring.find("-", i)\
    if j == -1:\
        version = verstring[i:]\
        release = None\
    else:\
        version = verstring[i:j]\
        release = verstring[j + 1:]\
    return (epoch, version, release)\
\
\
v1 = sys.argv[1]\
operator = sys.argv[2]\
v2 = sys.argv[3]\
rc = rpm.labelCompare(stringToEVR(v1), stringToEVR(v2))\
sys.exit(0 if operator == ("<", "==", ">")[rc + 1] else 1)\
'

## In %pre, %post on upgrade or downgrade:
##   Compare the uninstalling package version string and the specified one
## In %preun, %postun on upgrade or downgrade:
##   Compare the installing package version string and the specified one
%ver_cmp_opposite(n:) \
(\
  ver_opposite=$(%{expand:%%{ver_opposite %{-n*}}})\
  [[ -z $ver_opposite ]] && exit 1\
  %{ver_cmp} "$ver_opposite" "%{1}" "%{2}"\
)