Fix incorrect types for sensing_of

They can return 0 if the sprite does not exist
Fixes #262
Closes #325
(this one uses a different fix and has tests)

There are broader issues about compiled sensing_of not handling dynamic
sprite create/delete. We should tackle that later. The other PR wouldn't
really fix this either.

Author: GarboMuffin

src/compiler/irgen.js

@@ -520,6 +520,7 @@ class ScriptTreeGenerator {
             }
 
             if (object.isConstant('_stage_')) {
+                // We assume that the stage always exists, so these don't need to be able to return 0.
                 switch (property) {
                 case 'background #': // fallthrough for scratch 1.0 compatibility
                 case 'backdrop #':
@@ -528,6 +529,7 @@ class ScriptTreeGenerator {
                     return new IntermediateInput(InputOpcode.SENSING_OF_BACKDROP_NAME, InputType.STRING);
                 }
             } else {
+                // If the target sprite does not exist, these may all return 0, even the costume name one.
                 switch (property) {
                 case 'x position':
                     return new IntermediateInput(InputOpcode.SENSING_OF_POS_X, InputType.NUMBER, {object});
@@ -536,11 +538,11 @@ class ScriptTreeGenerator {
                 case 'direction':
                     return new IntermediateInput(InputOpcode.SENSING_OF_DIRECTION, InputType.NUMBER_REAL, {object});
                 case 'costume #':
-                    return new IntermediateInput(InputOpcode.SENSING_OF_COSTUME_NUMBER, InputType.NUMBER_POS_INT, {object});
+                    return new IntermediateInput(InputOpcode.SENSING_OF_COSTUME_NUMBER, InputType.NUMBER_POS_INT | InputType.NUMBER_ZERO, {object});
                 case 'costume name':
-                    return new IntermediateInput(InputOpcode.SENSING_OF_COSTUME_NAME, InputType.STRING, {object});
+                    return new IntermediateInput(InputOpcode.SENSING_OF_COSTUME_NAME, InputType.STRING | InputType.NUMBER_ZERO, {object});
                 case 'size':
-                    return new IntermediateInput(InputOpcode.SENSING_OF_SIZE, InputType.NUMBER_POS, {object});
+                    return new IntermediateInput(InputOpcode.SENSING_OF_SIZE, InputType.NUMBER_POS | InputType.NUMBER_ZERO, {object});
                 }
             }
 

test/fixtures/execute/tw-sensing-of-non-existent-costume-name.sb3

@@ -0,0 +1,13 @@
+// TW Snapshot
+// Input SHA-256: c3b1a45369f15f6809142ef2a2c6d1a680b802b70524a499b347af1008730a03
+
+// Sprite1 script
+(function factoryXYZ(thread) { const target = thread.target; const runtime = target.runtime; const stage = runtime.getTargetForStage();
+const b0 = runtime.getSpriteTargetByName("Sprite2");
+return function* genXYZ () {
+runtime.ext_scratch3_looks._say("plan 0", target);
+if ((("" + (b0 ? b0.getCostumes()[b0.currentCostume].name : 0)).toLowerCase() === "a".toLowerCase())) {
+}
+runtime.ext_scratch3_looks._say("end", target);
+retire(); return;
+}; })

test/snapshot/__snapshots__/tw-sensing-of-non-existent-costume-name.sb3.tw-snapshot

@@ -35,7 +35,7 @@ runtime.ext_scratch3_looks._say("pass direction", target);
 if (((b1 ? b1.currentCostume + 1 : 0) === 3)) {
 runtime.ext_scratch3_looks._say("pass costume #", target);
 }
-if (((b1 ? b1.getCostumes()[b1.currentCostume].name : 0).toLowerCase() === "Costume name test".toLowerCase())) {
+if ((("" + (b1 ? b1.getCostumes()[b1.currentCostume].name : 0)).toLowerCase() === "Costume name test".toLowerCase())) {
 runtime.ext_scratch3_looks._say("pass costume name", target);
 }
 if (((b1 ? b1.size : 0) === 76.01)) {

test/snapshot/__snapshots__/tw-sensing-of.sb3.tw-snapshot

@@ -0,0 +1,13 @@
+// TW Snapshot
+// Input SHA-256: c3b1a45369f15f6809142ef2a2c6d1a680b802b70524a499b347af1008730a03
+
+// Sprite1 script
+(function factoryXYZ(thread) { const target = thread.target; const runtime = target.runtime; const stage = runtime.getTargetForStage();
+const b0 = runtime.getSpriteTargetByName("Sprite2");
+return function* genXYZ () {
+runtime.ext_scratch3_looks._say("plan 0", target);
+if ((("" + (b0 ? b0.getCostumes()[b0.currentCostume].name : 0)).toLowerCase() === "a".toLowerCase())) {
+}
+runtime.ext_scratch3_looks._say("end", target);
+retire(); return;
+}; })

test/snapshot/__snapshots__/warp-timer/tw-sensing-of-non-existent-costume-name.sb3.tw-snapshot

@@ -35,7 +35,7 @@ runtime.ext_scratch3_looks._say("pass direction", target);
 if (((b1 ? b1.currentCostume + 1 : 0) === 3)) {
 runtime.ext_scratch3_looks._say("pass costume #", target);
 }
-if (((b1 ? b1.getCostumes()[b1.currentCostume].name : 0).toLowerCase() === "Costume name test".toLowerCase())) {
+if ((("" + (b1 ? b1.getCostumes()[b1.currentCostume].name : 0)).toLowerCase() === "Costume name test".toLowerCase())) {
 runtime.ext_scratch3_looks._say("pass costume name", target);
 }
 if (((b1 ? b1.size : 0) === 76.01)) {