Send block updates to the computer when updating redstone

Fixes #1520

projects/common/src/main/java/dan200/computercraft/shared/computer/blocks/AbstractComputerBlockEntity.java

@@ -199,6 +199,11 @@ protected ComputerSide remapLocalSide(ComputerSide localSide) {
         return localSide;
     }
 
+    private void updateRedstoneInputs(ServerComputer computer) {
+        var pos = getBlockPos();
+        for (var dir : DirectionUtil.FACINGS) updateRedstoneInput(computer, dir, pos.relative(dir));
+    }
+
     private void updateRedstoneInput(ServerComputer computer, Direction dir, BlockPos targetPos) {
         var offsetSide = dir.getOpposite();
         var localDir = remapToLocalSide(dir);
@@ -254,8 +259,7 @@ private void updateInputAt(BlockPos neighbour) {
 
         // If the position is not any adjacent one, update all inputs. This is pretty terrible, but some redstone mods
         // handle this incorrectly.
-        var pos = getBlockPos();
+        updateRedstoneInputs(computer);
-        for (var dir : DirectionUtil.FACINGS) updateRedstoneInput(computer, dir, pos.relative(dir));
         invalidSides = (1 << 6) - 1; // Mark all peripherals as dirty.
     }
 
@@ -264,9 +268,10 @@ private void updateInputAt(BlockPos neighbour) {
      */
     public void updateOutput() {
         BlockEntityHelpers.updateBlock(this);
-        for (var dir : DirectionUtil.FACINGS) {
+        for (var dir : DirectionUtil.FACINGS) RedstoneUtil.propagateRedstoneOutput(getLevel(), getBlockPos(), dir);
-            RedstoneUtil.propagateRedstoneOutput(getLevel(), getBlockPos(), dir);
+
-        }
+        var computer = getServerComputer();
+        if (computer != null) updateRedstoneInputs(computer);
     }
 
     protected abstract ServerComputer createComputer(int id);

projects/common/src/main/java/dan200/computercraft/shared/util/RedstoneUtil.java

@@ -50,6 +50,8 @@ public static void propagateRedstoneOutput(Level world, BlockPos pos, Direction
 
         var neighbourPos = pos.relative(side);
         world.neighborChanged(neighbourPos, block.getBlock(), pos);
-        world.updateNeighborsAtExceptFromFacing(neighbourPos, block.getBlock(), side.getOpposite());
+        // We intentionally use updateNeighborsAt here instead of updateNeighborsAtExceptFromFacing, as computers can
+        // both send and receive redstone, and so also need to be updated.
+        world.updateNeighborsAt(neighbourPos, block.getBlock());
     }
 }

projects/common/src/testMod/kotlin/dan200/computercraft/gametest/Computer_Test.kt

@@ -22,6 +22,7 @@
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertTrue
 import org.lwjgl.glfw.GLFW
+import kotlin.time.Duration.Companion.milliseconds
 
 class Computer_Test {
     /**
@@ -71,6 +72,24 @@ fun Set_and_destroy(context: GameTestHelper) = context.sequence {
         thenExecute { context.assertBlockHas(lamp, RedstoneLampBlock.LIT, false, "Lamp should not be lit") }
     }
 
+    /**
+     * Check computers pick up propagated redstone to surrounding blocks.
+     *
+     * @see [#1520](https://github.com/cc-tweaked/CC-Tweaked/issues/1520)
+     */
+    @GameTest
+    fun Self_output_update(context: GameTestHelper) = context.sequence {
+        thenOnComputer {
+            getApi<RedstoneAPI>().setOutput(ComputerSide.BACK, true)
+            sleep(100.milliseconds)
+            assertEquals(true, getApi<RedstoneAPI>().getInput(ComputerSide.BACK), "Input should be on")
+
+            getApi<RedstoneAPI>().setOutput(ComputerSide.BACK, false)
+            sleep(100.milliseconds)
+            assertEquals(false, getApi<RedstoneAPI>().getInput(ComputerSide.BACK), "Input should be off")
+        }
+    }
+
     /**
      * Check computers and turtles expose peripherals.
      */

projects/common/src/testMod/resources/data/cctest/structures/computer_test.self_output_update.snbt

@@ -0,0 +1,137 @@
+{
+    DataVersion: 3120,
+    size: [5, 5, 5],
+    data: [
+        {pos: [0, 0, 0], state: "minecraft:polished_andesite"},
+        {pos: [0, 0, 1], state: "minecraft:polished_andesite"},
+        {pos: [0, 0, 2], state: "minecraft:polished_andesite"},
+        {pos: [0, 0, 3], state: "minecraft:polished_andesite"},
+        {pos: [0, 0, 4], state: "minecraft:polished_andesite"},
+        {pos: [1, 0, 0], state: "minecraft:polished_andesite"},
+        {pos: [1, 0, 1], state: "minecraft:polished_andesite"},
+        {pos: [1, 0, 2], state: "minecraft:polished_andesite"},
+        {pos: [1, 0, 3], state: "minecraft:polished_andesite"},
+        {pos: [1, 0, 4], state: "minecraft:polished_andesite"},
+        {pos: [2, 0, 0], state: "minecraft:polished_andesite"},
+        {pos: [2, 0, 1], state: "minecraft:polished_andesite"},
+        {pos: [2, 0, 2], state: "minecraft:polished_andesite"},
+        {pos: [2, 0, 3], state: "minecraft:polished_andesite"},
+        {pos: [2, 0, 4], state: "minecraft:polished_andesite"},
+        {pos: [3, 0, 0], state: "minecraft:polished_andesite"},
+        {pos: [3, 0, 1], state: "minecraft:polished_andesite"},
+        {pos: [3, 0, 2], state: "minecraft:polished_andesite"},
+        {pos: [3, 0, 3], state: "minecraft:polished_andesite"},
+        {pos: [3, 0, 4], state: "minecraft:polished_andesite"},
+        {pos: [4, 0, 0], state: "minecraft:polished_andesite"},
+        {pos: [4, 0, 1], state: "minecraft:polished_andesite"},
+        {pos: [4, 0, 2], state: "minecraft:polished_andesite"},
+        {pos: [4, 0, 3], state: "minecraft:polished_andesite"},
+        {pos: [4, 0, 4], state: "minecraft:polished_andesite"},
+        {pos: [0, 1, 0], state: "minecraft:air"},
+        {pos: [0, 1, 1], state: "minecraft:air"},
+        {pos: [0, 1, 2], state: "minecraft:air"},
+        {pos: [0, 1, 3], state: "minecraft:air"},
+        {pos: [0, 1, 4], state: "minecraft:air"},
+        {pos: [1, 1, 0], state: "minecraft:air"},
+        {pos: [1, 1, 1], state: "minecraft:air"},
+        {pos: [1, 1, 2], state: "minecraft:air"},
+        {pos: [1, 1, 3], state: "minecraft:air"},
+        {pos: [1, 1, 4], state: "minecraft:air"},
+        {pos: [2, 1, 0], state: "minecraft:air"},
+        {pos: [2, 1, 1], state: "minecraft:air"},
+        {pos: [2, 1, 2], state: "computercraft:computer_advanced{facing:north,state:on}", nbt: {ComputerId: 1, Label: "computer_test.self_output_update", On: 1b, id: "computercraft:computer_advanced"}},
+        {pos: [2, 1, 3], state: "minecraft:polished_andesite"},
+        {pos: [2, 1, 4], state: "minecraft:air"},
+        {pos: [3, 1, 0], state: "minecraft:air"},
+        {pos: [3, 1, 1], state: "minecraft:air"},
+        {pos: [3, 1, 2], state: "minecraft:air"},
+        {pos: [3, 1, 3], state: "minecraft:air"},
+        {pos: [3, 1, 4], state: "minecraft:air"},
+        {pos: [4, 1, 0], state: "minecraft:air"},
+        {pos: [4, 1, 1], state: "minecraft:air"},
+        {pos: [4, 1, 2], state: "minecraft:air"},
+        {pos: [4, 1, 3], state: "minecraft:air"},
+        {pos: [4, 1, 4], state: "minecraft:air"},
+        {pos: [0, 2, 0], state: "minecraft:air"},
+        {pos: [0, 2, 1], state: "minecraft:air"},
+        {pos: [0, 2, 2], state: "minecraft:air"},
+        {pos: [0, 2, 3], state: "minecraft:air"},
+        {pos: [0, 2, 4], state: "minecraft:air"},
+        {pos: [1, 2, 0], state: "minecraft:air"},
+        {pos: [1, 2, 1], state: "minecraft:air"},
+        {pos: [1, 2, 2], state: "minecraft:air"},
+        {pos: [1, 2, 3], state: "minecraft:air"},
+        {pos: [1, 2, 4], state: "minecraft:air"},
+        {pos: [2, 2, 0], state: "minecraft:air"},
+        {pos: [2, 2, 1], state: "minecraft:air"},
+        {pos: [2, 2, 2], state: "minecraft:air"},
+        {pos: [2, 2, 3], state: "minecraft:air"},
+        {pos: [2, 2, 4], state: "minecraft:air"},
+        {pos: [3, 2, 0], state: "minecraft:air"},
+        {pos: [3, 2, 1], state: "minecraft:air"},
+        {pos: [3, 2, 2], state: "minecraft:air"},
+        {pos: [3, 2, 3], state: "minecraft:air"},
+        {pos: [3, 2, 4], state: "minecraft:air"},
+        {pos: [4, 2, 0], state: "minecraft:air"},
+        {pos: [4, 2, 1], state: "minecraft:air"},
+        {pos: [4, 2, 2], state: "minecraft:air"},
+        {pos: [4, 2, 3], state: "minecraft:air"},
+        {pos: [4, 2, 4], state: "minecraft:air"},
+        {pos: [0, 3, 0], state: "minecraft:air"},
+        {pos: [0, 3, 1], state: "minecraft:air"},
+        {pos: [0, 3, 2], state: "minecraft:air"},
+        {pos: [0, 3, 3], state: "minecraft:air"},
+        {pos: [0, 3, 4], state: "minecraft:air"},
+        {pos: [1, 3, 0], state: "minecraft:air"},
+        {pos: [1, 3, 1], state: "minecraft:air"},
+        {pos: [1, 3, 2], state: "minecraft:air"},
+        {pos: [1, 3, 3], state: "minecraft:air"},
+        {pos: [1, 3, 4], state: "minecraft:air"},
+        {pos: [2, 3, 0], state: "minecraft:air"},
+        {pos: [2, 3, 1], state: "minecraft:air"},
+        {pos: [2, 3, 2], state: "minecraft:air"},
+        {pos: [2, 3, 3], state: "minecraft:air"},
+        {pos: [2, 3, 4], state: "minecraft:air"},
+        {pos: [3, 3, 0], state: "minecraft:air"},
+        {pos: [3, 3, 1], state: "minecraft:air"},
+        {pos: [3, 3, 2], state: "minecraft:air"},
+        {pos: [3, 3, 3], state: "minecraft:air"},
+        {pos: [3, 3, 4], state: "minecraft:air"},
+        {pos: [4, 3, 0], state: "minecraft:air"},
+        {pos: [4, 3, 1], state: "minecraft:air"},
+        {pos: [4, 3, 2], state: "minecraft:air"},
+        {pos: [4, 3, 3], state: "minecraft:air"},
+        {pos: [4, 3, 4], state: "minecraft:air"},
+        {pos: [0, 4, 0], state: "minecraft:air"},
+        {pos: [0, 4, 1], state: "minecraft:air"},
+        {pos: [0, 4, 2], state: "minecraft:air"},
+        {pos: [0, 4, 3], state: "minecraft:air"},
+        {pos: [0, 4, 4], state: "minecraft:air"},
+        {pos: [1, 4, 0], state: "minecraft:air"},
+        {pos: [1, 4, 1], state: "minecraft:air"},
+        {pos: [1, 4, 2], state: "minecraft:air"},
+        {pos: [1, 4, 3], state: "minecraft:air"},
+        {pos: [1, 4, 4], state: "minecraft:air"},
+        {pos: [2, 4, 0], state: "minecraft:air"},
+        {pos: [2, 4, 1], state: "minecraft:air"},
+        {pos: [2, 4, 2], state: "minecraft:air"},
+        {pos: [2, 4, 3], state: "minecraft:air"},
+        {pos: [2, 4, 4], state: "minecraft:air"},
+        {pos: [3, 4, 0], state: "minecraft:air"},
+        {pos: [3, 4, 1], state: "minecraft:air"},
+        {pos: [3, 4, 2], state: "minecraft:air"},
+        {pos: [3, 4, 3], state: "minecraft:air"},
+        {pos: [3, 4, 4], state: "minecraft:air"},
+        {pos: [4, 4, 0], state: "minecraft:air"},
+        {pos: [4, 4, 1], state: "minecraft:air"},
+        {pos: [4, 4, 2], state: "minecraft:air"},
+        {pos: [4, 4, 3], state: "minecraft:air"},
+        {pos: [4, 4, 4], state: "minecraft:air"}
+    ],
+    entities: [],
+    palette: [
+        "minecraft:polished_andesite",
+        "minecraft:air",
+        "computercraft:computer_advanced{facing:north,state:on}"
+    ]
+}