gdext 0.4.3: Extensions fail to load on Android (aarch64-linux-android) when built with 0.4.3

[riverfr0zen]

Recently I upgraded to godot 0.4.3, and my extension stopped working (fails to load) on Android.

This only affects Android for me. The extension works fine on Linux builds with godot 0.4.3.

If I build with godot pinned to 0.4.2 (godot = "=0.4.2" in Cargo.toml), the extension works as expected on Android.

Supplying a bunch of details below. Please let me know if you'd like to see anything else. Thanks.

Environment

• gdext version: 0.4.3 (broken) vs 0.4.2 (working)
• Godot version: 4.5.1.stable.official.f62fdbde1
• Platform: Android (tested on physical device, Pixel 8a, via Godot's Remote Deploy)
• Target: aarch64-linux-android
• Rust version: Latest stable

Invocation

The extension is added as a child to my Game scene, and in Game.gd, I am loading it as so:

func _ready():
    var from_rust = $ImageOptimizer.testfn(20.0)
    print("From rust: " + str(from_rust))

adb logcat output

Used command: adb logcat | grep -E "(godot|mak3rs|ImageOptimizer|GDExtension|FATAL|dlopen)"

adb logcat of Extension built with 0.4.3 (fails to load):

11-30 23:02:50.555 31384 31437 I godot   : Vulkan 1.4.303 - Forward Mobile - Using Device #0: ARM - Mali-G715
11-30 23:02:50.671 31384 31437 I godot   :
11-30 23:02:51.648 31384 31437 E godot   : ERROR: Cannot get class 'ImageOptimizer'.
11-30 23:02:51.648 31384 31437 E godot   :    at: _instantiate_internal (core/object/class_db.cpp:546)
11-30 23:02:51.648 31384 31437 E godot   : WARNING: Node ImageOptimizer of type ImageOptimizer cannot be created. A placeholder will be created instead.
11-30 23:02:51.648 31384 31437 E godot   :    at: instantiate (scene/resources/packed_scene.cpp:277)
11-30 23:02:51.850 31384 31437 E godot   : SCRIPT ERROR: Invalid call. Nonexistent function 'testfn' in base 'Node'.
11-30 23:02:51.850 31384 31437 E godot   :    at: _ready (res://Game.gd:127)
11-30 23:02:51.850 31384 31437 E godot   :    GDScript backtrace (most recent call first):
11-30 23:02:51.850 31384 31437 E godot   :        [0] _ready (res://Game.gd:127)

adb logcat of extension built with 0.4.2 (loading succeeds):

11-30 23:12:35.257 32135 32180 I godot   : Vulkan 1.4.303 - Forward Mobile - Using Device #0: ARM - Mali-G715
11-30 23:12:35.395 32135 32180 I godot   :
11-30 23:12:36.457 32135 32180 I godot   : [INFO] mak3rs::imageopt: ImageOptimizer initialized
11-30 23:12:36.662 32135 32180 I godot   : [INFO] mak3rs::imageopt: In testfn, doing 2 * 20
11-30 23:12:36.662 32135 32180 I godot   : From rust: 40.0

With simplified test extension

Since my ImageOptimizer extension is quite involved, I also created a simple test extension to troubleshoot:

lib.rs

use godot::prelude::*;

struct TestExt;

#[gdextension]
unsafe impl ExtensionLibrary for TestExt {}

#[derive(GodotClass)]
#[class(base=Node)]
pub struct SimpleTest {
    #[base]
    base: Base<Node>,
}

#[godot_api]
impl INode for SimpleTest {
    fn init(base: Base<Node>) -> Self {
        godot_print!("SimpleTest initialized");
        Self { base }
    }
}

#[godot_api]
impl SimpleTest {
    #[func]
    pub fn hello(&self, name: GString) -> GString {
        godot_print!("Hello called with: {}", name);
        let result = format!("Hello, {}!", name);
        GString::from(&result)
    }
}

Cargo.toml

[package]
name = "testext"
version = "0.1.0"
edition = "2021"

[lib]
crate-type = ["cdylib"]

[dependencies]
godot = "0.4.3"
# If godot is pinned to 0.4.2, the extension works fine on Android
# godot = "=0.4.2"

TestExt.gdextension

[configuration]
entry_symbol = "gdext_rust_init"
compatibility_minimum = 4.1

[libraries]
linux.release.x86_64 = "res://testext/target/release/libtestext.so"
linux.debug.x86_64 = "res://testext/target/release/libtestext.so"

android.debug.arm64 = "res://testext/target/aarch64-linux-android/release/libtestext.so"
android.release.arm64 = "res://testext/target/aarch64-linux-android/release/libtestext.so"

Invocation in Game.gd

func _ready():
    print($SimpleTest.hello("yoyo"))
    var from_rust = $ImageOptimizer.testfn(20.0)
    print("From rust: " + str(from_rust))

With all necessary env vars configured, the extension was built with: cargo build --target aarch64-linux-android --lib --release

adb logcat output with simple extension

adb logcat of simple extension built with 0.4.3 (SimpleTest fails to load, while my ImageOptimizer, built with 0.4.2, initializes):

12-01 00:39:36.380  6531  6577 E godot   : ERROR: Cannot get class 'SimpleTest'.
12-01 00:39:36.380  6531  6577 E godot   :    at: _instantiate_internal (core/object/class_db.cpp:546)
12-01 00:39:36.380  6531  6577 E godot   : WARNING: Node SimpleTest of type SimpleTest cannot be created. A placeholder will be created instead.
12-01 00:39:36.380  6531  6577 E godot   :    at: instantiate (scene/resources/packed_scene.cpp:277)
12-01 00:39:36.381  6531  6577 I godot   : [INFO] mak3rs::imageopt: ImageOptimizer initialized
12-01 00:39:36.591  6531  6577 E godot   : SCRIPT ERROR: Invalid call. Nonexistent function 'hello' in base 'Node'.
12-01 00:39:36.591  6531  6577 E godot   :    at: _ready (res://Game.gd:127)
12-01 00:39:36.591  6531  6577 E godot   :    GDScript backtrace (most recent call first):
12-01 00:39:36.591  6531  6577 E godot   :        [0] _ready (res://Game.gd:127)

adb logcat of simple extension built with 0.4.2 (everything works):

12-01 00:43:30.626  6863  6929 I godot   : Vulkan 1.4.303 - Forward Mobile - Using Device #0: ARM - Mali-G715
12-01 00:43:30.759  6863  6929 I godot   :
12-01 00:43:31.661  6863  6929 I godot   : SimpleTest initialized
12-01 00:43:31.661  6863  6929 I godot   : [INFO] mak3rs::imageopt: ImageOptimizer initialized
12-01 00:43:31.865  6863  6929 I godot   : Hello called with: yoyo
12-01 00:43:31.865  6863  6929 I godot   : Hello, yoyo!
12-01 00:43:31.865  6863  6929 I godot   : [INFO] mak3rs::imageopt: In testfn, doing 2 * 20
12-01 00:43:31.865  6863  6929 I godot   : From rust: 40.0

[Bromeon]

Thanks for the report!

Are you 100% sure the godot crate version is the only difference between the two deployments?
Same Godot version, all other Rust dependencies identical, same toolchain setup, etc?

These are the changes between 0.4.2 and 0.4.3.
Possible candidates for regressions might be:

• Update runtime_version to use non-deprecated get_godot_version pointer. #1394 followed by github.com/Fix get_godot_version2 unavailable on older builds #1403
• Failed ptrcalls: instead of panic, print error + return default  #1387
• Start phasing out #[cfg(debug_assertions)] in favor of safeguards #1395

Is there a chance you can test with intermediate commits between the two releases, to narrow down where it could have been introduced?

[riverfr0zen]

Yeah, pretty sure, since I was trying to narrow things down. I simply toggle between the below two in Cargo.toml between builds (same machine, same env, etc.), and get the results above. I've done it several times with each version in succession, so I don't think there are any other differences.

# Temporarily pinning to 0.4.2 due to Android issue
godot = "=0.4.2"
# godot = "0.4.3"

I'll take a look at trying the intermediate commits. Not sure how soon I'll be able to get to them, but I'll update here if I do.

[dajmitonapake]

Hey, I had similiar problem, but on every godot-rust version. Adding features = ["experimental-threads"] fixed it, so maybe it is somehow related to your issue?

[Bromeon]

If experimental-threads solves it, could you guys provide me with some logs that indicate the problem? Unfortunately the ones in the initial post here aren't very conclusive, so I wonder if there are more that aren't visible?

Also because experimental-threads is not a long-term solution, and may change over time... so if we can track the problem down now, we know better what to look for (and can maybe even add a regression test). Thanks!

[riverfr0zen]

"experimental-threads"

Thanks @dajmitonapake ! Adding the "experimental-threads" feature does indeed fix the problem. With the feature enabled, I am able to build with 0.4.3 and not encounter the instantiation error (or any other errors). The extensions seem to work as expected.

Also, I tested the intermediate commits and identified that PR #1395 ("Start phasing out #[cfg(debug_assertions)] in favor of safeguards") introduced the regression.

Below is the testing report (binary search approach):

Commit	PR	Status
c76238c	https://github.com/godot-rust/gdext/releases/tag/v0.4.2	✅ WORKS
47aef2e	#1387 - Failed ptrcalls	✅ WORKS
18f94ac	#1393 - Array functional ops	✅ WORKS
9182513	#1394 - Update runtime_version	✅ WORKS
53043c9	#1395 - Phase out debug_assertions	❌ BROKEN ⬅️
6ffe8a6	#1397 - Macro hygiene fix	❌ BROKEN
d236ee0	https://github.com/godot-rust/gdext/releases/tag/v0.4.3	❌ BROKEN

Re: more logs, I don't see any further log messages than the ones I provided. If there are any particular search patterns you'd like me to use, please let me know.

[Bromeon]

Thanks so much @riverfr0zen, that's really helpful! ❤️

Do you currently build for Android in Rust's dev ("Debug mode") or release profile ("Release mode", --release)?

Could you maybe check if specifying the following Cargo features also solve the issue -- without having experimental-threads set?

• in dev mode: safeguards-dev-balanced
• in release mode: safeguards-release-disengaged

[riverfr0zen]

I use the release profile. Can confirm that "safeguards-release-disengaged", without "experimental-threads", also solves the issue.

Is this recommended over "experimental-threads" (until further issue resolution)?