Game sends ships to unreachable port causiong an exception

[hessenfarmer]

Describe the bug
see https://www.widelands.org/forum/topic/5978/
if a port is unreachable and a ship gets send to it the game throws an exception.

To reproduce
Steps to reproduce the behavior:

1. load the attached savegame
2. wait for the crash

see attached screenshot as well

Expected behavior
maps should not allow a port space in this place
ships should not be sent to such a port.

Screenshots
If applicable, add screenshots to help explain your problem.

Savegames

2024-04-27T23.12.16.wgf.zip

Version:

• OS: all
  widelands latest.

Additional context
Add any other context about the problem here.

[bunnybot]

Mirrored on Codeberg as #CB4807.

[bunnybot]

Mirrored from Codeberg
On Wed May 01 21:43:43 CEST 2024, frankystone wrote:

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That port in the screenshot shouldn't be reachable at all, because water needs to have a distance of two nodes to be navigable by ships.
Where you can build bridges, a ship can't navigate, regardless if a bridge/road is there or not.

[bunnybot]

Mirrored from Codeberg
On Wed May 01 21:44:37 CEST 2024, Benedikt Straub (Nordfriese) wrote:

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Not entirely sure about the description. Placing a road cannot interfere with ship movement since ships can only move onto nodes that are entirely surrounded by 6 water triangles, and no road or bridge can be built there.

Maybe the savegame is from v1.1? There was a bug in v1.1 where ships could in some cases move over land, so it might be that due to this bug the two oceans in the screenshot would have been one fleet then but are two separate fleets now.

[bunnybot]

Mirrored from Codeberg
On Wed May 01 21:57:20 CEST 2024, Stephan Lutz (hessenfarmer) wrote:

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According to the forum post this is an autosave from 1.2, However I might ask whether he continued a game from 1.1

[bunnybot]

Mirrored from Codeberg
On Wed May 01 22:02:22 CEST 2024, Stephan Lutz (hessenfarmer) wrote:

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well I am not sure. How near do we need to get to the port dock to reach it. This may be a corner case as the port dock is just at the point surrounded by 6 water triangles left to the southern bridge.

[bunnybot]

Mirrored from Codeberg
On Wed May 01 22:41:19 CEST 2024, Stephan Lutz (hessenfarmer) wrote:

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in the forum the player comnfirmed the whole game was played with 1.2.

[hessenfarmer]

I uploaded the wrong savegame. I have coreccted it now in the original post

[hessenfarmer]

While fixing the broken game in Multiplayer I found that the real bug is two fold.

1. I'd rate the misplaced port space in the map a bug. As no port should be allowed there, as the "ocean" or fleet space of this port is only 1 field where only the port dock can go.
2. that the ships get send to this port seems to be a bug as well.

[frankystone]

Hm, with a deeper look at the map there might be more problematic portspaces. At those positions (coordinates in white) it may depend on the place of the portdock if the port is reachable or not: