Assert in map.cpp when terraforming under a shop

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Build shop
2. Terraform land beneath it
3. Boom.

gdb stuffs:

NOT_REACHED triggered at line 369 of map.cpp
Program received signal SIGABRT, Aborted.
0x00007ffff6e46475 in raise () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) bt
#0  0x00007ffff6e46475 in raise () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007ffff6e496f0 in abort () from /lib/x86_64-linux-gnu/libc.so.6
#2  0x0000000000404edf in error (s=0x427cd0 "NOT_REACHED triggered at line %i 
of %s") at main.cpp:43
#3  0x0000000000406355 in VoxelWorld::GetGroundHeight (this=0x63fca0, x=9, y=8) 
at map.cpp:369
#4  0x0000000000406765 in TerrainChanges::GetGroundData (this=0x7fffffffdfa0, 
pos=...) at map.cpp:458
#5  0x0000000000406bf5 in TerrainChanges::ChangeCorner (this=0x7fffffffdfa0, 
pos=..., corner=SL_FLAT, direction=-1) at map.cpp:510
#6  0x0000000000406af9 in TerrainChanges::ChangeCorner (this=0x7fffffffdfa0, 
pos=..., corner=TC_EAST, direction=-1) at map.cpp:500
#7  0x0000000000406af9 in TerrainChanges::ChangeCorner (this=0x7fffffffdfa0, 
pos=..., corner=TC_SOUTH, direction=-1) at map.cpp:500
#8  0x000000000041f987 in TileTerraformMouseMode::OnMouseWheelEvent 
(this=0x691bf0, vp=0x7a8630, direction=-1) at viewport.cpp:979
#9  0x000000000041ec01 in Viewport::OnMouseWheelEvent (this=0x7a8630, 
direction=-1) at viewport.cpp:1025
#10 0x0000000000426c40 in WindowManager::MouseWheelEvent (this=0x691cc0, 
direction=-1) at window.cpp:825
#11 0x0000000000405299 in main () at main.cpp:175

Possibly relates to Issue#9 as supports are not created when they should be

Original issue reported on code.google.com by CharlesP...@googlemail.com on 10 Nov 2012 at 3:34

[GoogleCodeExporter]

Original comment by Alberth2...@gmail.com on 11 Nov 2012 at 5:25

• Changed title: Assert in map.cpp when terraforming under a shop

[GoogleCodeExporter]

The NOT_REACHED happens when it fails to find a ground at all heights at a 
given (x,y). This was indeed the case with shops, as before r543, building a 
shop means the ground was removed. In r543 the combination shop and ground in a 
single position is allowed again, which should stop this crash from happening.

(Terraforming still does weird things to shops though :) )

Original comment by Alberth2...@gmail.com on 30 Nov 2012 at 6:38

[GoogleCodeExporter]

Fixed in the terraforming updates

Original comment by CharlesP...@googlemail.com on 15 Dec 2012 at 5:15

• Changed state: Fixed