You can break blocks from the road while merging is in progress

Server Implementation

Paper

Server Version

1.16.5

Describe the bug

Copy of https://issues.intellectualsites.com/issue/PS-169 by Diranus.

When you merge with "/p merge", the plot owner and trusted players can build/break blocks inside the road between.
It seems like the plot area is merged internally before the roads are removed, resulting in break/build permissions in road not intended for building/breaking.

To Reproduce

• Player A claims at least two adjacent plots
• Player A trusts Player B on them.
• Player B is standing on one of the plot and attempts to build/break blocks in the road between
• Player A invokes the merge process by "/p merge"
• For a short period of time, player B can break or build on the road, until the road disappears by the merging process.

The larger the merged plot is, the longer that period is.

Expected behaviour

Screenshots / Videos

Error log (if applicable)

The only console output is that player A typed "/p merge"

Plot Debugpaste

PlotSquared Version

5.13.6

Checklist

• I have included a Plot debugpaste.
• I am using the newest build from https://www.spigotmc.org/resources/77506/ and the issue still persists.

Anything else?

It allows some duping which harms multiplayer worlds.
Especially if the plot borders, walls or the road itself is out of valueful materials (for example, a beacon border or a road out of some value stone).
In our servers, strong fast break potion effects can be activated by the players which amplifies this issue (you can break multiple blocks out of the road in the short time between /p merge and completion of merging process).

Start at the /p merge command and trace the merge process described in the reproduction steps. Verify when plot permissions begin covering the road and when the road is removed. Done means trusted players cannot build or break road blocks at any point while adjacent plots are merging, including for larger merged plots.