Fix redstone comparator flooding crash by erlehmann #2027

cora · 2022-02-24T20:09:55+01:00

cora commented

2022-02-24 20:09:55 +01:00

Redstone comparators have two modes, comparison mode & subtraction mode.
Before this patch, the functions to turn comparators on or off attempted
to swap nodes with comparators in the same mode, but failed to determine
the correct replacement node, if the existing node was not a comparator.

When a comparator in an on state (e.g. powered by a filled cauldron) was
flooded, the flooding dropped the comparator and replaced the comparator
node that was to be swapped out with air, which lead to a server crash.

This patch changes the functions that turn comparators on or off so they
only swap existing nodes with comparators in the same mode if the name
of the replacement node can be determined – i.e. if it is not nil.

Redstone comparators have two modes, comparison mode & subtraction mode. Before this patch, the functions to turn comparators on or off attempted to swap nodes with comparators in the same mode, but failed to determine the correct replacement node, if the existing node was not a comparator. When a comparator in an on state (e.g. powered by a filled cauldron) was flooded, the flooding dropped the comparator and replaced the comparator node that was to be swapped out with air, which lead to a server crash. This patch changes the functions that turn comparators on or off so they only swap existing nodes with comparators in the same mode if the name of the replacement node can be determined – i.e. if it is not nil.

cora added 1 commit 2022-02-24 20:10:02 +01:00

41550da87b Fix redstone comparator flooding crash

Redstone comparators have two modes, comparison mode & subtraction mode.
Before this patch, the functions to turn comparators on or off attempted
to swap nodes with comparators in the same mode, but failed to determine
the correct replacement node, if the existing node was not a comparator.

When a comparator in an on state (e.g. powered by a filled cauldron) was
flooded, the flooding dropped the comparator and replaced the comparator
node that was to be swapped out with air, which lead to a server crash.

This patch changes the functions that turn comparators on or off so they
only swap existing nodes with comparators in the same mode if the name
of the replacement node can be determined – i.e. if it is not nil.

cora commented

2022-02-24 22:34:59 +01:00

I'm merging this since it was extensively tested in mcla ( Mineclonia/Mineclonia#284 ). I verified that it works in mcl2 too ofc.

I'm merging this since it was extensively tested in mcla ( https://git.minetest.land/Mineclonia/Mineclonia/pulls/284 ). I verified that it works in mcl2 too ofc.

cora merged commit 85e0e23c76 into master

2022-02-24 22:35:14 +01:00

cora referenced this issue from a commit

2022-02-24 22:35:14 +01:00

Merge pull request 'Fix redstone comparator flooding crash by erlehmann' (#2027) from fix-comparator-crash into master

cora deleted branch fix-comparator-crash

2022-02-24 22:35:21 +01:00

cora referenced this pull request

2022-02-25 01:22:20 +01:00

Crash caused by flooding of redstone comparator. #2012

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