[2021] Significant bug within item filters - invisible items under certain Continue statements

I have found a combination of actions that results in completely invisible items. Posting this for awarness because anyone can accidentally make items invisible which obviously is a huge deal - you won't even notice you lost some (potentially valueable) drops unless there is an icon/sound effect added. Call this #filtergate if you want.

Example screen

- here you can see the item label is completely invisible. The item is only noticeable because it has influence and some sockets. Otherwise there is absolutely nothing.

How to reproduce:

• Any matching block with RGBA text/background color + Continue
• Any matching block with RGB text/background color

Expected result (1 of these):

• override first block color with second block color, keeping first block alpha
• override first block color with second block color, using default alpha (240 - slightly transparent)

Actual result:

• override first block color with second block color, using alpha = 0 (completely transparent)

Basically, you can accidentally get fully transparent colors even if you never write any 0 in filter file.

My suspect is that this is some uninitialized memory and/or logic bug - basically if you apply RGBA with Continue and then apply RGB the A always gets value of 0 which means fully transparent. Pinging /u/RhysGGG because of numerous help in the past in any filter-related topic.

Minimal filter without any 0s that makes everything invisible (uncomment 255 to fix it):

Show
    SetBackgroundColor 100 255 100 255
    SetTextColor       100 255 100 255
    Continue

Show
    SetBackgroundColor 255 100 100 # 255
    SetTextColor       255 100 100 # 255

How to defend yourself from #filtergate before it's fixed - do one of:

• always use RGB
• always use RGBA
• never use Continue

Edit: bug report thread: https://www.pathofexile.com/forum/view-thread/3084331

External link →