[archlinux] Pacman 5.2.0 support: adding and removing programs process are stuck.

This is a follow up of bug #687 (closed).

When I want to add a program within pamac (development version and liblalpm 12), process is stuck on check for file conflicts step.

I tried to add claws-mail, and here is the log I have in pamac output - sorry for the french translation:

Préparation...
Synchronisation des bases de données des paquets...
Résolution des dépendances...
Recherche des conflits entre paquets...

Vérification de l’intégrité des paquets...
Chargement des fichiers des paquets...
Analyse des conflits entre fichiers...

I had to kill pamac-manager and remove /var/lib/pacman/db.lck.

I also see same kind of problems removing package. Here is the log of claws-mail I installed by hand.

Préparation...
Vérification des dépendances...
Désinstallation de claws-mail (3.17.4-2)...
Désinstallation de libetpan (1.9.3-1)...
Désinstallation de compface (1.5.2-8)...

Remove process is stuck.

Here is my /etc/pamac.conf file:

### Pamac configuration file

## When removing a package, also remove those dependencies
## that are not required by other packages (recurse option):
RemoveUnrequiredDeps

## How often to check for updates, value in hours (0 to disable):
RefreshPeriod = 6

## When there are no updates available, hide the tray icon:
#NoUpdateHideIcon

## When applying updates, enable packages downgrade:
#EnableDowngrade

## Allow Pamac to search and install packages from AUR:
EnableAUR

## Keep built packages from AUR in cache after installation:
#KeepBuiltPkgs

## When AUR support is enabled check for updates from AUR:
CheckAURUpdates

## When check updates from AUR support is enabled check for vcs updates:
#CheckAURVCSUpdates

## AUR build directory:
BuildDirectory = /var/tmp

## Number of versions of each package to keep in the cache:
KeepNumPackages = 3

## Remove only the versions of uninstalled packages when clean cache:
#OnlyRmUninstalled

## Download updates in background
#DownloadUpdates

## Maximum Parallel Downloads
MaxParallelDownloads = 0

I deactivated parallel downloads because they're not working great on Archlinux.

Any idea?