[Zig 0.16.X+] fix SDL3 example for Zig 0.16.X and add panic handling back in (no stack trace support) (#69)

- fix SDL3 example for Zig 0.16.X
- add panic handling back in (no stack trace support) for Zig 0.16.X

Fixes #68

Author: silbinarywolf

build.zig

@@ -76,6 +76,8 @@ pub fn build(b: *std.Build) void {
             .target = target,
             .optimize = optimize,
         });
+        zig016.addImport("ndk", ndk_module);
+        zig016.addImport("android_builtin", android_builtin_module);
         android_module.addImport("zig016", zig016);
     }
 

examples/minimal/src/minimal.zig

@@ -12,8 +12,8 @@ pub const std_options: std.Options = if (builtin.abi.isAndroid())
 else
     .{};
 
-/// Deprecated: Zig 0.15.2 and lower only, Custom panic handler for Android
-pub const panic = if (builtin.abi.isAndroid() and builtin.zig_version.major == 0 and builtin.zig_version.minor <= 15)
+/// Custom panic handler for Android
+pub const panic = if (builtin.abi.isAndroid())
     android.panic
 else
     std.debug.FullPanic(std.debug.defaultPanic);

examples/raylib/src/main.zig

@@ -19,8 +19,8 @@ pub fn main() !void {
     }
 }
 
-/// Deprecated: Zig 0.15.2 and lower only, Custom panic handler for Android
-pub const panic = if (builtin.abi.isAndroid() and builtin.zig_version.major == 0 and builtin.zig_version.minor <= 15)
+/// Custom panic handler for Android
+pub const panic = if (builtin.abi.isAndroid())
     android.panic
 else
     std.debug.FullPanic(std.debug.defaultPanic);

examples/sdl2/src/sdl-zig-demo.zig

@@ -14,8 +14,8 @@ pub const std_options: std.Options = if (builtin.abi.isAndroid())
 else
     .{};
 
-/// Deprecated: Zig 0.15.2 and lower only, Custom panic handler for Android
-pub const panic = if (builtin.abi.isAndroid() and builtin.zig_version.major == 0 and builtin.zig_version.minor <= 15)
+// Custom panic handler for Android
+pub const panic = if (builtin.abi.isAndroid())
     android.panic
 else
     std.debug.FullPanic(std.debug.defaultPanic);
@@ -28,24 +28,23 @@ comptime {
 
 /// This needs to be exported for Android builds
 fn SDL_main() callconv(.c) void {
-    if (comptime builtin.abi.isAndroid()) {
-        if (builtin.zig_version.major == 0 and builtin.zig_version.minor <= 14) {
-            _ = std.start.callMain();
-        } else if (builtin.zig_version.major == 0 and builtin.zig_version.minor <= 15) {
-            main() catch |err| {
-                log.err("{s}", .{@errorName(err)});
-                if (@errorReturnTrace()) |trace| {
-                    if (builtin.zig_version.major == 0 and builtin.zig_version.minor <= 15) {
-                        std.debug.dumpStackTrace(trace.*);
-                    } else {
-                        std.debug.dumpStackTrace(trace);
-                    }
-                }
-            };
-        }
-    } else {
+    if (!comptime builtin.abi.isAndroid()) {
         @compileError("SDL_main should not be called outside of Android builds");
     }
+    if (builtin.zig_version.major == 0 and builtin.zig_version.minor <= 14) {
+        _ = std.start.callMain();
+        return;
+    }
+    main() catch |err| {
+        log.err("{s}", .{@errorName(err)});
+        if (@errorReturnTrace()) |trace| {
+            if (builtin.zig_version.major == 0 and builtin.zig_version.minor <= 15) {
+                std.debug.dumpStackTrace(trace.*);
+            } else {
+                std.debug.dumpStackTrace(trace);
+            }
+        }
+    };
 }
 
 pub fn main() !void {

src/android/android.zig

@@ -13,7 +13,7 @@ const Level = ndk.Level;
 pub const panic = if (builtin.zig_version.major == 0 and builtin.zig_version.minor <= 15)
     std.debug.FullPanic(@import("Zig015_Panic.zig").panic)
 else
-    @compileError("Android panic handler is no longer maintained as of Zig 0.16.x-dev");
+    std.debug.FullPanic(zig016.panic);
 
 /// Alternate log function implementation that calls __android_log_write so that you can see the logging via "adb logcat"
 pub const logFn = if (builtin.zig_version.major == 0 and builtin.zig_version.minor <= 14)

src/android/zig016/zig016.zig

@@ -1,6 +1,11 @@
 //! Seperate module for Zig 0.16.X-dev functionality as @Type() comptime directive was removed
 
 const std = @import("std");
+const builtin = @import("builtin");
+const ndk = @import("ndk");
+
+const android_builtin = @import("android_builtin");
+const package_name: ?[*:0]const u8 = if (android_builtin.package_name.len > 0) android_builtin.package_name else null;
 
 const LogFunction = fn (comptime message_level: std.log.Level, comptime scope: @EnumLiteral(), comptime format: []const u8, args: anytype) void;
 
@@ -20,3 +25,78 @@ pub fn wrapLogFn(comptime logFn: fn (
         }
     }.standardLogFn;
 }
+
+pub fn panic(message: []const u8, first_trace_addr: ?usize) noreturn {
+    @branchHint(.cold);
+    if (comptime !builtin.abi.isAndroid()) @compileError("do not use Android panic for non-Android builds");
+
+    const android_log_level: c_int = @intFromEnum(ndk.Level.fatal);
+
+    trace: {
+        _ = ndk.__android_log_print(android_log_level, package_name, "panic: %.*s", message.len, message.ptr);
+
+        if (@errorReturnTrace()) |t| if (t.index > 0) {
+            logFatal("error return context:");
+            writeStackTrace(t) catch break :trace;
+            logFatal("\nstack trace:\n");
+        };
+        if (!std.options.allow_stack_tracing) {
+            logFatal("Cannot print stack trace: stack tracing is disabled");
+            return;
+        } else {
+            _ = ndk.__android_log_print(android_log_level, package_name, "  at address: 0x%X", first_trace_addr orelse @returnAddress());
+            logFatal("  (stack trace printing not supported in Zig 0.16.X+ for Android SDK)");
+        }
+    }
+
+    @trap();
+}
+
+/// Write a previously captured stack trace to `writer`, annotated with source locations.
+pub fn writeStackTrace(st: *const std.builtin.StackTrace) !void {
+    if (!std.options.allow_stack_tracing) {
+        logFatal("Cannot print stack trace: stack tracing is disabled");
+        return;
+    }
+
+    // Fetch `st.index` straight away. Aside from avoiding redundant loads, this prevents issues if
+    // `st` is `@errorReturnTrace()` and errors are encountered while writing the stack trace.
+    const n_frames = st.index;
+    if (n_frames == 0) return logFatal("(empty stack trace)");
+
+    const captured_frames = @min(n_frames, st.instruction_addresses.len);
+    logFatal("(stack trace support unimplemented for Zig 0.16.X+)");
+
+    // const di_gpa = std.debug.getDebugInfoAllocator();
+    // const di = std.debug.getSelfDebugInfo() catch |err| switch (err) {
+    //     error.UnsupportedTarget => {
+    //         logFatal("Cannot print stack trace: debug info unavailable for target\n\n");
+    //         return;
+    //     },
+    // };
+    // const io = std.Options.debug_io;
+    //
+    // for (st.instruction_addresses[0..captured_frames]) |ret_addr| {
+    //     // `ret_addr` is the return address, which is *after* the function call.
+    //     // Subtract 1 to get an address *in* the function call for a better source location.
+    //     try printSourceAtAddress(di_gpa, io, di, t, ret_addr -| StackIterator.ra_call_offset);
+    // }
+    if (n_frames > captured_frames) {
+        _ = ndk.__android_log_print(
+            @intFromEnum(ndk.Level.fatal),
+            package_name,
+            "(%d additional stack frames skipped...)",
+            n_frames - captured_frames,
+        );
+    }
+}
+
+inline fn logFatal(text: []const u8) void {
+    _ = ndk.__android_log_print(
+        @intFromEnum(ndk.Level.fatal),
+        package_name,
+        "%.*s",
+        text.len,
+        text.ptr,
+    );
+}