Make backtraces optional (#648)

You probably don't want backtraces if you're doing multiboot and in a
few other cases.

Also #646 broke the build if you didn't use the `testing` feature, so
I've updated the `justfile` so that a CI run checks that agb builds
correctly both without the `testing` feature and without the `backtrace`
feature. The `backtrace` feature implies the testing feature to make
things a bit simpler.

- [x] Changelog updated

CHANGELOG.md

@@ -11,7 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Added a new crash screen which provides a mechanism for seeing a full stack trace of your program when it panics.
   This requires a change to your `.cargo/config.toml`. You must add the rust flag `"-Cforce-frame-pointers=yes"` to
-  your rustflags field.
+  your rustflags field. This can also be disabled by removing the `backtrace` feature.
 - Initial unicode support for font rendering.
 - Kerning support for font rendering.
 
@@ -52,7 +52,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Replaced `.show()` and `.hide()` with `.set_visible()`in `RegularMap`, `AffineMap` and `InfiniteScrolledMap`.
 - Added `.into_inner()` to `InfiniteScrolledMap` to get the map back once you are done using it in the `InfiniteScrolledMap`.
 - Added `.hflip()`, `.vflip()`, `.priority()`, `.position()` to `ObjectUnmanaged` and `Object`.
-- An abstraction over hblank DMA to allow for cool effects like gradients and circular windows. See the dma_effect* examples.
+- An abstraction over hblank DMA to allow for cool effects like gradients and circular windows. See the dma_effect\* examples.
 - Expermental and incomplete support for MIDI files with agb-tracker.
 - Fixnum now implements [`num::Num`](https://docs.rs/num/0.4/num/trait.Num.html) from the [`num`](https://crates.io/crates/num) crate.
 - `Default` implementations for `RandomNumberGenerator`, `InitOnce` and `RawMutex`.

agb/Cargo.toml

@@ -8,7 +8,8 @@ license = "MPL-2.0"
 repository = "https://github.com/agbrs/agb"
 
 [features]
-default = ["testing"]
+default = ["backtrace", "testing"]
+backtrace = ["testing", "dep:qrcodegen-no-heap"]
 testing = []
 multiboot = []
 
@@ -20,7 +21,7 @@ agb_macros = { version = "0.19.1", path = "../agb-macros" }
 agb_fixnum = { version = "0.19.1", path = "../agb-fixnum" }
 agb_hashmap = { version = "0.19.1", path = "../agb-hashmap" }
 bilge = "0.2"
-qrcodegen-no-heap = "1.8"
+qrcodegen-no-heap = { version = "1.8", optional = true }
 portable-atomic = { version = "1.6.0", default-features = false, features = ["unsafe-assume-single-core"] }
 once_cell = { version = "1.19.0", default-features = false, features = ["critical-section"] }
 critical-section = { version = "1.1.2", features = ["restore-state-u16"] }

agb/src/lib.rs

@@ -150,6 +150,7 @@ extern crate alloc;
 mod agb_alloc;
 
 mod agbabi;
+#[cfg(feature = "backtrace")]
 mod backtrace;
 mod bitarray;
 /// Implements everything relating to things that are displayed on screen.
@@ -167,6 +168,7 @@ pub mod mgba;
 pub use agb_fixnum as fixnum;
 /// Contains an implementation of a hashmap which suits the gameboy advance's hardware.
 pub use agb_hashmap as hash_map;
+#[cfg(feature = "backtrace")]
 mod panics_render;
 /// Simple random number generator
 pub mod rng;
@@ -201,10 +203,8 @@ pub use {agb_alloc::ExternalAllocator, agb_alloc::InternalAllocator};
 #[panic_handler]
 #[allow(unused_must_use)]
 fn panic_implementation(info: &core::panic::PanicInfo) -> ! {
-    use core::fmt::Write;
     if let Some(mut mgba) = mgba::Mgba::new() {
-        write!(mgba, "{}", info);
-        mgba.set_level(mgba::DebugLevel::Fatal);
+        let _ = mgba.print(format_args!("{info}"), mgba::DebugLevel::Fatal);
     }
 
     #[allow(clippy::empty_loop)]
@@ -296,8 +296,6 @@ impl Gba {
 /// You can run the tests using `cargo test`, but it will work better through `mgba-test-runner` by
 /// running something along the lines of `CARGO_TARGET_THUMBV4T_NONE_EABI_RUNNER=mgba-test-runner cargo test`.
 pub mod test_runner {
-    use self::panics_render::render_backtrace;
-
     use super::*;
 
     #[doc(hidden)]
@@ -327,13 +325,20 @@ pub mod test_runner {
 
     #[panic_handler]
     fn panic_implementation(info: &core::panic::PanicInfo) -> ! {
+        #[cfg(feature = "backtrace")]
         let frames = backtrace::unwind_exception();
 
         if let Some(mut mgba) = mgba::Mgba::new() {
             let _ = mgba.print(format_args!("[failed]"), mgba::DebugLevel::Error);
         }
 
-        render_backtrace(&frames, info);
+        #[cfg(feature = "backtrace")]
+        crate::panics_render::render_backtrace(&frames, info);
+
+        #[cfg(not(feature = "backtrace"))]
+        loop {
+            syscall::halt();
+        }
     }
 
     static mut TEST_GBA: Option<Gba> = None;

justfile

@@ -4,18 +4,22 @@ CLIPPY_ARGUMENTS := "-Dwarnings -Dclippy::all -Aclippy::empty-loop"
 build: build-roms
 
 build-debug:
-    just _build-debug agb
-    just _build-debug tracker/agb-tracker
+    (cd agb && cargo build --no-default-features)
+    (cd agb && cargo build --no-default-features --features=testing)
+    (cd agb && cargo build --examples --tests)
+
+    (cd tracker/agb-tracker && cargo build --examples --tests)
+
 build-release:
-    just _build-release agb
-    just _build-release tracker/agb-tracker
+    (cd agb && cargo build --examples --tests --release)
+
 clippy:
     just _all-crates _clippy
 
 test:
     just _test-debug agb
-    just _test-multiboot
     just _test-debug tracker/agb-tracker
+    just _test-multiboot
     just _test-debug-arm agb
 
 test-release:
@@ -162,17 +166,11 @@ _all-crates target:
         just "{{target}}" "$PROJECT_DIR" || exit $?; \
     done
 
-_build-debug crate:
-    (cd "{{crate}}" && cargo build --examples --tests)
-_build-release crate:
-    (cd "{{crate}}" && cargo build --release --examples --tests)
 _test-release crate:
-    just _build-release {{crate}}
     (cd "{{crate}}" && cargo test --release)
 _test-release-arm crate:
     (cd "{{crate}}" && cargo test --release --target=armv4t-none-eabi)
 _test-debug crate:
-    just _build-debug {{crate}}
     (cd "{{crate}}" && cargo test)
 _test-debug-arm crate:
     (cd "{{crate}}" && cargo test --target=armv4t-none-eabi)