README

Differences between deb & RPM scripts

During an upgrade of a deb package from one version to another, the following steps happen:

1. The new version is unpacked, with the new files overwriting the old files.
2. The after-remove of the old version is called.
3. The old files are removed.
4. The after-install of the new version is called.

See:

• Debian Policy Manual: Upgrading a package.
• Debian Policy Manual: Details of unpack phase of installation or upgrade

However, when you upgrade an RPM package, the scriptlets are called in a reverse order:

1. The new version is unpacked, with the new files overwriting the old files.
2. The after-install of the new version is called.
3. The old files are removed.
4. The after-remove of the old version is called.

See Fedora Docs: Scriptlets - Ordering.

This has direct consequences when attempting to use the same scripts for both targets.