buildingplanner suspending stairs

[Myos-tis]

DFHack version 50.13-r2 (git: 7efaca9) on x86_64

Stairs, like the one to the right of the screenshot, seem to get unreasonably suspended despite being walkable.

[chdoc]

@Myos-tis If you click on the stairs, what reason does suspendmanager give for keeping the stairs suspended? Also, could you provide screenshots of the z-levels above and below the stair that is being wrongly suspended?

[chdoc]

I have localized at least one issue with suspending dead ends:

               if (isImpassable(building)) {
                    // suspend the current construction job to leave the entire plan suspended
                    suspensions[job->id] = Reason::DEADEND;

and

           // ...and continue the exploration from its position
           building = exit;

Basically, the job being suspended is not the construction job for the building that is checked for being impassible.

I have to run now, but I should be able to propose a fix tonight. I also want to do some minor refactoring while I am at it.

@myk002 can you assign me to this?

[Myos-tis]

It's suspended due to blocking another build job.

The area pictured is 11x16x5, from (74,47) in the top left to (84,62) in the bottom right

z=54 (64, embark lowest is -10)

z=53 (63)

Despite being symmetrical, the stairs on the west pillar are not suspended

z=52 (62)

Again, the stairs on the west pillar aren't suspended, and in the middle, the stairs to the left of the east pillar aren't suspended either

Removing the middle stairs or allowing the walls below to be built doesn't change anything

z=51 (61)

z=50 (60)

All of the planned walls are bronze, all of the planned stairs are obsidian