Properly erroring for invalid indexes in gpu.get now and (probably?) fixing a bug in term.isWide.

src/main/resources/assets/opencomputers/loot/OpenOS/lib/term.lua

@@ -81,17 +81,20 @@ function term.setCursorBlink(enabled)
 end
 
 function term.isWide(x, y)
-  local charLeft, char = component.gpu.get(x - 1, y), component.gpu.get(x, y)
+  local char = component.gpu.get(x, y)
   if unicode.isWide(char) then
     -- The char at the specified position is a wide char.
     return true
-  elseif char == " " and charLeft and unicode.isWide(charLeft) then
-    -- The char left to the specified position is a wide char.
-    return true, true
-  else
-    -- Not a wide char.
-    return false
   end
+  if char == " " and x > 1 then
+    local charLeft = component.gpu.get(x - 1, y)
+    if charLeft and unicode.isWide(charLeft) then
+      -- The char left to the specified position is a wide char.
+      return true, true
+    end
+  end
+  -- Not a wide char.
+  return false
 end
 
 function term.isAvailable()

src/main/scala/li/cil/oc/common/component/TextBuffer.scala

@@ -273,25 +273,31 @@ class TextBuffer(val owner: Container) extends ManagedComponent with api.compone
 
   override def getForegroundColor(column: Int, row: Int) =
     if (isForegroundFromPalette(column, row)) {
-      PackedColor.extractForeground(data.color(row)(column))
+      PackedColor.extractForeground(color(column, row))
     }
     else {
-      PackedColor.unpackForeground(data.color(row)(column), data.format)
+      PackedColor.unpackForeground(color(column, row), data.format)
     }
 
   override def isForegroundFromPalette(column: Int, row: Int) =
-    data.format.isFromPalette(PackedColor.extractForeground(data.color(row)(column)))
+    data.format.isFromPalette(PackedColor.extractForeground(color(column, row)))
 
   override def getBackgroundColor(column: Int, row: Int) =
     if (isBackgroundFromPalette(column, row)) {
-      PackedColor.extractBackground(data.color(row)(column))
+      PackedColor.extractBackground(color(column, row))
     }
     else {
-      PackedColor.unpackBackground(data.color(row)(column), data.format)
+      PackedColor.unpackBackground(color(column, row), data.format)
     }
 
   override def isBackgroundFromPalette(column: Int, row: Int) =
-    data.format.isFromPalette(PackedColor.extractBackground(data.color(row)(column)))
+    data.format.isFromPalette(PackedColor.extractBackground(color(column, row)))
+
+  private def color(column: Int, row: Int) = {
+    if (column < 0 || column >= getWidth || row < 0 || row >= getHeight)
+      throw new IndexOutOfBoundsException()
+    else data.color(row)(column)
+  }
 
   @SideOnly(Side.CLIENT)
   override def renderText() = relativeLitArea != 0 && proxy.render()

src/main/scala/li/cil/oc/util/TextBuffer.scala

@@ -95,7 +95,11 @@ class TextBuffer(var width: Int, var height: Int, initialFormat: PackedColor.Col
   }
 
   /** Get the char at the specified index. */
-  def get(col: Int, row: Int) = buffer(row)(col)
+  def get(col: Int, row: Int) = {
+    if (col < 0 || col >= width || row < 0 || row >= height)
+      throw new IndexOutOfBoundsException()
+    else buffer(row)(col)
+  }
 
   /** String based fill starting at a specified location. */
   def set(col: Int, row: Int, s: String, vertical: Boolean): Boolean =