All rail types can be supported by trapdoors even when the trapdoor is open. This used to affect redstone repeaters, wire, and comparaters, but no longer does.
Steps to Reproduce:
Place a trap door down in the 'open=false' and 'half=top' blockstate
Place down one of the affected blocks in the "Notes" section on top of the trapdoor
Open the trapdoor with your hand, or redstone
Observed Results:
The block will not break, but instead float above the (mostly) empty supporting block.
Expected Results:
The block would break as there is no block beneath it to support it properly.
Screenshots/Videos:
[media]Notes:
Related to other supporting block issues:
MC-92758 MC-264563 MC-148202 MC-222212 MC-213638Standing signs and banners were added to this issue, but later removed, as they were not part of the original issue, and have unique placement behavior unrelated to rails (the last affected block).
Original Description:
(The original description of the issue when it was triaged, by @unknown)
When a trapdoor is in the flat form (Closed) it is possible to place rails on them. This would be fine except that you can then open the trapdoor and still have the rail on top of it. This is a fully functional rail, however when the block is updated by anything other than the rail, it pops off as it should directly after the trapdoor is opened. Attached is a video showing everything I have described.
This also applies to e.g. redstone dust and repeaters. Other blocks like torches do pop off though
Linked issues
is duplicated by 7
MC-165428
Trapdoor glitch
Resolved
MC-167961
Redstone components on trapdoor doesn't get destroyed
Resolved
MC-177008
Trapdoors do not update some blocks above when opened manually
Resolved
MC-181928
Redstone & Trapdoor
Resolved
MC-194547
Rails on top half trapdoors do not break if the trapdoor below them opens
Resolved
Attachments
Comments 23
Requesting ownership of this issue has it is outdated, and needs to be updated. I would also like to maintain it going forward.
Are signs really an issue here? They can be placed on top of bottom slabs too, heck wall signs can be placed on other wall signs with the same facing state. They never consider the block states of their supporting block.
Fair point. Noteworthy that banners also share the same behavior as standing signs (being placeable on top of other blocks which one would think doesn't support it).
Rails were the last affected block affected by this behavior in the original issue, so I can remove banners and standing signs if that's considered seperate behavior. I've added the original description to the issue for clarity.
[Mod] Jingy
Opening a trapdoor should give a single block update in the direction of which the top face was facing