avm2: Enable stack traces for Flash Player 11.5+ and SWF18+

core/src/avm2/globals/error.rs

@@ -4,6 +4,7 @@ use crate::avm2::string::AvmString;
 use crate::avm2::value::Value;
 use crate::avm2::Error;
 use crate::avm2::TObject;
+use crate::PlayerMode;
 
 pub fn call_handler<'gc>(
     activation: &mut Activation<'_, 'gc>,
@@ -24,6 +25,22 @@ pub fn get_stack_trace<'gc>(
 ) -> Result<Value<'gc>, Error<'gc>> {
     let this = this.as_object().unwrap();
 
+    // See <https://docs.ruffle.rs/en_US/FlashPlatform/reference/actionscript/3/Error.html#getStackTrace()>
+    // But note that the behavior also depends on SWF version.
+    let stack_trace_enabled = if activation.context.player_version >= 18
+        && activation.caller_movie_or_root().version() >= 18
+    {
+        // For Flash Player 11.5+ and SWF>=18, stack traces are always enabled.
+        true
+    } else {
+        // For Flash Player Player 11.4 and earlier, or for SWF<18, stack traces are enabled for debug only.
+        activation.context.player_mode == PlayerMode::Debug
+    };
+
+    if !stack_trace_enabled {
+        return Ok(Value::Null);
+    }
+
     if let Some(error) = this.as_error_object() {
         let call_stack = error.call_stack();
         if !call_stack.is_empty() {

core/src/avm2/object/error_object.rs

@@ -10,7 +10,6 @@ use crate::string::WString;
 use core::fmt;
 use gc_arena::{Collect, Gc, GcWeak};
 use std::fmt::Debug;
-use tracing::{enabled, Level};
 
 /// A class instance allocator that allocates Error objects.
 pub fn error_allocator<'gc>(
@@ -19,9 +18,8 @@ pub fn error_allocator<'gc>(
 ) -> Result<Object<'gc>, Error<'gc>> {
     let base = ScriptObjectData::new(class);
 
-    let call_stack = (enabled!(Level::INFO) || cfg!(feature = "avm_debug"))
-        .then(|| activation.avm2().call_stack().borrow().clone())
-        .unwrap_or_default();
+    // Stack trace is always collected for debugging purposes.
+    let call_stack = activation.avm2().call_stack().borrow().clone();
 
     Ok(ErrorObject(Gc::new(
         activation.gc(),

core/src/context.rs

@@ -41,6 +41,7 @@ use crate::stub::StubCollection;
 use crate::tag_utils::{SwfMovie, SwfSlice};
 use crate::timer::Timers;
 use crate::vminterface::Instantiator;
+use crate::PlayerMode;
 use core::fmt;
 use gc_arena::{Collect, Mutation};
 use rand::rngs::SmallRng;
@@ -84,6 +85,8 @@ pub struct UpdateContext<'gc> {
     /// variables.
     pub player_version: u8,
 
+    pub player_mode: PlayerMode,
+
     /// Requests that the player re-renders after this execution (e.g. due to `updateAfterEvent`).
     pub needs_render: &'gc mut bool,
 

core/src/lib.rs

@@ -68,7 +68,7 @@ pub use events::PlayerEvent;
 pub use font::DefaultFont;
 pub use indexmap;
 pub use loader::LoadBehavior;
-pub use player::{Player, PlayerBuilder, PlayerRuntime, StaticCallstack};
+pub use player::{Player, PlayerBuilder, PlayerMode, PlayerRuntime, StaticCallstack};
 pub use ruffle_render::backend::ViewportDimensions;
 pub use swf;
 pub use swf::Color;

core/src/player.rs

@@ -298,6 +298,9 @@ pub struct Player {
     #[allow(unused)]
     player_runtime: PlayerRuntime,
 
+    /// Whether we're emulating the release or the debug build.
+    player_mode: PlayerMode,
+
     swf: Arc<SwfMovie>,
 
     run_state: RunState,
@@ -2179,6 +2182,7 @@ impl Player {
 
             let mut update_context = UpdateContext {
                 player_version: this.player_version,
+                player_mode: this.player_mode,
                 swf: &mut this.swf,
                 library,
                 rng: &mut this.rng,
@@ -2454,6 +2458,7 @@ pub struct PlayerBuilder {
     gamepad_button_mapping: HashMap<GamepadButton, KeyCode>,
     player_version: Option<u8>,
     player_runtime: PlayerRuntime,
+    player_mode: PlayerMode,
     quality: StageQuality,
     page_url: Option<String>,
     frame_rate: Option<f64>,
@@ -2505,6 +2510,7 @@ impl PlayerBuilder {
             gamepad_button_mapping: HashMap::new(),
             player_version: None,
             player_runtime: PlayerRuntime::default(),
+            player_mode: PlayerMode::default(),
             quality: StageQuality::High,
             page_url: None,
             frame_rate: None,
@@ -2679,6 +2685,12 @@ impl PlayerBuilder {
         self
     }
 
+    /// Configures the player mode (default is `PlayerMode::Release`)
+    pub fn with_player_mode(mut self, mode: PlayerMode) -> Self {
+        self.player_mode = mode;
+        self
+    }
+
     // Configure the embedding page's URL (if applicable)
     pub fn with_page_url(mut self, page_url: Option<String>) -> Self {
         self.page_url = page_url;
@@ -2859,6 +2871,7 @@ impl PlayerBuilder {
                 instance_counter: 0,
                 player_version,
                 player_runtime: self.player_runtime,
+                player_mode: self.player_mode,
                 run_state: if self.autoplay {
                     RunState::Playing
                 } else {
@@ -3043,3 +3056,11 @@ impl FromStr for PlayerRuntime {
         Ok(player_runtime)
     }
 }
+
+#[derive(Default, Clone, Copy, Debug, Eq, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize))]
+pub enum PlayerMode {
+    #[default]
+    Release,
+    Debug,
+}

tests/framework/src/options.rs

@@ -7,7 +7,7 @@ use approx::relative_eq;
 use image::ImageFormat;
 use regex::Regex;
 use ruffle_core::tag_utils::SwfMovie;
-use ruffle_core::{PlayerBuilder, PlayerRuntime, ViewportDimensions};
+use ruffle_core::{PlayerBuilder, PlayerMode, PlayerRuntime, ViewportDimensions};
 use ruffle_render::backend::RenderBackend;
 use ruffle_render::quality::StageQuality;
 use serde::Deserialize;
@@ -150,6 +150,7 @@ pub struct PlayerOptions {
     with_audio: bool,
     with_video: bool,
     runtime: PlayerRuntime,
+    mode: PlayerMode,
 }
 
 impl PlayerOptions {
@@ -172,7 +173,9 @@ impl PlayerOptions {
             player_builder = player_builder.with_audio(TestAudioBackend::default());
         }
 
-        player_builder = player_builder.with_player_runtime(self.runtime);
+        player_builder = player_builder
+            .with_player_runtime(self.runtime)
+            .with_player_mode(self.mode);
 
         if self.with_video {
             #[cfg(feature = "ruffle_video_external")]

tests/tests/swfs/avm2/error_stack_trace_debug_swf17/Test.as

@@ -0,0 +1,22 @@
+package {
+import flash.display.*;
+import flash.geom.*;
+
+[SWF(width="10", height="10")]
+public class Test extends Sprite {
+    public function Test() {
+        var st = new Error().getStackTrace();
+        var rect = new Sprite();
+        if (st === null) {
+            rect.graphics.beginFill(0xFF0000);
+        } else if (st === undefined) {
+            rect.graphics.beginFill(0x00FF00);
+        } else {
+            rect.graphics.beginFill(0x0000FF);
+        }
+        rect.graphics.drawRect(0, 0, 10, 10);
+        rect.graphics.endFill();
+        addChild(rect);
+    }
+}
+}

tests/tests/swfs/avm2/error_stack_trace_debug_swf17/test.toml

@@ -0,0 +1,8 @@
+num_ticks = 1
+
+[image_comparisons.output]
+tolerance = 0
+
+[player_options]
+mode = "Debug"
+with_renderer = { optional = false, sample_count = 4 }

tests/tests/swfs/avm2/error_stack_trace_debug_swf18/Test.as

@@ -0,0 +1,22 @@
+package {
+import flash.display.*;
+import flash.geom.*;
+
+[SWF(width="10", height="10")]
+public class Test extends Sprite {
+    public function Test() {
+        var st = new Error().getStackTrace();
+        var rect = new Sprite();
+        if (st === null) {
+            rect.graphics.beginFill(0xFF0000);
+        } else if (st === undefined) {
+            rect.graphics.beginFill(0x00FF00);
+        } else {
+            rect.graphics.beginFill(0x0000FF);
+        }
+        rect.graphics.drawRect(0, 0, 10, 10);
+        rect.graphics.endFill();
+        addChild(rect);
+    }
+}
+}

tests/tests/swfs/avm2/error_stack_trace_debug_swf18/test.toml

@@ -0,0 +1,8 @@
+num_ticks = 1
+
+[image_comparisons.output]
+tolerance = 0
+
+[player_options]
+mode = "Debug"
+with_renderer = { optional = false, sample_count = 4 }

tests/tests/swfs/avm2/error_stack_trace_release_swf17/Test.as

@@ -0,0 +1,22 @@
+package {
+import flash.display.*;
+import flash.geom.*;
+
+[SWF(width="10", height="10")]
+public class Test extends Sprite {
+    public function Test() {
+        var st = new Error().getStackTrace();
+        var rect = new Sprite();
+        if (st === null) {
+            rect.graphics.beginFill(0xFF0000);
+        } else if (st === undefined) {
+            rect.graphics.beginFill(0x00FF00);
+        } else {
+            rect.graphics.beginFill(0x0000FF);
+        }
+        rect.graphics.drawRect(0, 0, 10, 10);
+        rect.graphics.endFill();
+        addChild(rect);
+    }
+}
+}

tests/tests/swfs/avm2/error_stack_trace_release_swf17/test.toml

@@ -0,0 +1,8 @@
+num_ticks = 1
+
+[image_comparisons.output]
+tolerance = 0
+
+[player_options]
+mode = "Release"
+with_renderer = { optional = false, sample_count = 4 }

tests/tests/swfs/avm2/error_stack_trace_release_swf18/Test.as

@@ -0,0 +1,22 @@
+package {
+import flash.display.*;
+import flash.geom.*;
+
+[SWF(width="10", height="10")]
+public class Test extends Sprite {
+    public function Test() {
+        var st = new Error().getStackTrace();
+        var rect = new Sprite();
+        if (st === null) {
+            rect.graphics.beginFill(0xFF0000);
+        } else if (st === undefined) {
+            rect.graphics.beginFill(0x00FF00);
+        } else {
+            rect.graphics.beginFill(0x0000FF);
+        }
+        rect.graphics.drawRect(0, 0, 10, 10);
+        rect.graphics.endFill();
+        addChild(rect);
+    }
+}
+}

tests/tests/swfs/avm2/error_stack_trace_release_swf18/test.toml

@@ -0,0 +1,8 @@
+num_ticks = 1
+
+[image_comparisons.output]
+tolerance = 0
+
+[player_options]
+mode = "Release"
+with_renderer = { optional = false, sample_count = 4 }