[I7-1879] [Mantis 1915] unhelpful error message produced when the player is declared to be carrying scenery

[curiousdannii-testing]

Reported by : mattweiner

Description :

When the player is declared to be carrying scenery, the last declaration that something is scenery in the code produces a "this looks like a contradiction" message; but the only sentence listed is the last scenery declaration, not the one in which it is declared that scenery is carried. (Which can make it very hard to track down the problem.)

Steps to reproduce :

Garden is a room.

The rock is scenery. The player carries the rock.

The carrot is scenery in the Garden.

Additional information :

Error message:

Problem. You wrote 'The carrot is scenery in the Garden' : but this looks like a contradiction, because the same property seems to be being set in each of these sentences, but with a different outcome.

If we delete the last line (or move it above the line before), we get the same message about "The rock is scenery." In neither case do we get a contradiction with "The player carries the rock," which is where the problem comes in.

Forum thread: http://www.intfiction.org/forum/viewtopic.php?f=7&t=20044&start=10
Note that one of the projects affected was Counterfeit Monkey, which made it very hard to track down the error! (Also suggesting that this is new in newer versions of Inform; I agree that it's a good idea to prevent scenery from being carried, but perhaps it should have a custom error message.)

imported from: [Mantis 1915] unhelpful error message produced when the player is declared to be carrying scenery

• status: Closed
• resolution: Resolved
• resolved: 2022-04-13T12:46:24+10:00
• imported: 2022/01/10

[curiousdannii-testing]

557058:4c095ffd-6d6f-47ce-9e73-77c613347b86:

Comment by zarf :
Check. In fact, it doesn't have to be a scenery declaration, it's just the last declaration overall.

Garden is a room.

The rock is scenery. The player carries the rock.
Steve is a person.

"You wrote 'Steve is a person' : but this looks like a contradiction, because the same property seems to be being set in each of these sentences, but with a different outcome."

[curiousdannii-testing]

61eedb62875fc10070240916:

Fixed via this commit: https://github.com/ganelson/inform/commit/98b832014eea06ca2bfc647e844d5a0d33bf108b

Comment by Graham Nelson:
It's quite hard for Inform to explain the slightly diffuse reasoning here, since an implication is involved. Still, I've improved matters somewhat -

Problem. You wrote 'The player carries the rock', but in another sentence 'Scenery is usually fixed in place': but this looks like a contradiction...