feat: more improvements to panic handling

Follow on panics no longer confuse the panic output and the just in
time debugger now works properly on the local tty.

build.zig.zon

@@ -15,8 +15,8 @@
             .hash = "dizzy-1.0.0-AAAAAM1wAAAiDbx_6RwcVEOBk8p2XOu8t9WPNc3K7kBK",
         },
         .thespian = .{
-            .url = "https://github.com/neurocyte/thespian/archive/829a8d33e92988a51a8c51d204ec766a28c7903d.tar.gz",
-            .hash = "thespian-0.0.1-owFOjs0TBgAAed7EtHDPtpB7NBn-riNjb7Rkc7a_Voow",
+            .url = "https://github.com/neurocyte/thespian/archive/b3176b32e62b7615908fa58c99167abbeb58bbc6.tar.gz",
+            .hash = "thespian-0.0.1-owFOjocZBgBvhsxDpjQoy0vRKrkP1S2HsxSNAnF8LRk2",
         },
         .themes = .{
             .url = "https://github.com/neurocyte/flow-themes/releases/download/master-952f9f630ea9544088fd30293666ee0650b7a690/flow-themes.tar.gz",

src/main.zig

@@ -149,11 +149,10 @@ pub fn main() anyerror!void {
         return list_languages.list(a, stdout.writer(), tty_config);
     }
 
-    if (builtin.os.tag != .windows)
-        if (std.posix.getenv("JITDEBUG")) |_|
-            thespian.install_debugger()
-        else if (@hasDecl(renderer, "install_crash_handler"))
-            renderer.install_crash_handler();
+    if (builtin.os.tag != .windows and @hasDecl(renderer, "install_crash_handler")) {
+        if (std.posix.getenv("JITDEBUG")) |_| renderer.jit_debugger_enabled = true;
+        renderer.install_crash_handler();
+    }
 
     if (args.debug_wait) {
         std.debug.print("press return to start", .{});

src/renderer/vaxis/renderer.zig

@@ -135,15 +135,46 @@ pub fn install_crash_handler() void {
     std.posix.sigaction(std.posix.SIG.ILL, &act, null);
 }
 
+pub var jit_debugger_enabled: bool = false;
+
 fn handle_crash(sig: i32, info: *const std.posix.siginfo_t, ctx_ptr: ?*anyopaque) callconv(.c) noreturn {
+    const debug = @import("std/debug.zig");
+    debug.lockStdErr();
+
+    if (panic_in_progress())
+        std.posix.abort();
+
     in_panic.store(true, .release);
     const cleanup = panic_cleanup;
     panic_cleanup = null;
+
     if (cleanup) |self| {
         self.vx.deinit(self.allocator, self.tty.anyWriter());
         self.tty.deinit();
     }
-    @import("std/debug.zig").handleSegfaultPosix(sig, info, ctx_ptr);
+    if (jit_debugger_enabled) {
+        handleSegfaultPosixNoAbort(sig, info, ctx_ptr);
+        @import("thespian").sighdl_debugger(sig, @ptrCast(@constCast(info)), ctx_ptr);
+        std.posix.abort();
+    } else {
+        debug.handleSegfaultPosix(sig, info, ctx_ptr);
+    }
+    unreachable;
+}
+
+fn handleSegfaultPosixNoAbort(sig: i32, info: *const std.posix.siginfo_t, ctx_ptr: ?*anyopaque) void {
+    const debug = @import("std/debug.zig");
+    debug.resetSegfaultHandler();
+    const addr = switch (builtin.os.tag) {
+        .linux => @intFromPtr(info.fields.sigfault.addr),
+        .freebsd, .macos => @intFromPtr(info.addr),
+        .netbsd => @intFromPtr(info.info.reason.fault.addr),
+        .openbsd => @intFromPtr(info.data.fault.addr),
+        .solaris, .illumos => @intFromPtr(info.reason.fault.addr),
+        else => unreachable,
+    };
+    const code = if (builtin.os.tag == .netbsd) info.info.code else info.code;
+    debug.dumpSegfaultInfoPosix(sig, code, addr, ctx_ptr);
 }
 
 pub fn run(self: *Self) Error!void {

src/renderer/vaxis/std/debug.zig

@@ -1380,7 +1380,7 @@ pub fn attachSegfaultHandler() void {
     updateSegfaultHandler(&act);
 }
 
-fn resetSegfaultHandler() void {
+pub fn resetSegfaultHandler() void {
     if (native_os == .windows) {
         if (windows_segfault_handle) |handle| {
             assert(windows.kernel32.RemoveVectoredExceptionHandler(handle) != 0);
@@ -1438,7 +1438,7 @@ pub fn handleSegfaultPosix(sig: i32, info: *const posix.siginfo_t, ctx_ptr: ?*an
     posix.abort();
 }
 
-fn dumpSegfaultInfoPosix(sig: i32, code: i32, addr: usize, ctx_ptr: ?*anyopaque) void {
+pub fn dumpSegfaultInfoPosix(sig: i32, code: i32, addr: usize, ctx_ptr: ?*anyopaque) void {
     const stderr = io.getStdErr().writer();
     _ = switch (sig) {
         posix.SIG.SEGV => if (native_arch == .x86_64 and native_os == .linux and code == 128) // SI_KERNEL

src/tui/tui.zig

@@ -105,8 +105,8 @@ fn init(allocator: Allocator) InitError!*Self {
     var conf, const conf_bufs = root.read_config(@import("config"), allocator);
     defer root.free_config(allocator, conf_bufs);
 
-    if (conf.start_debugger_on_crash)
-        tp.install_debugger();
+    if (@hasDecl(renderer, "install_crash_handler") and conf.start_debugger_on_crash)
+        renderer.jit_debugger_enabled = true;
 
     const theme_, const parsed_theme = get_theme_by_name(allocator, conf.theme) orelse get_theme_by_name(allocator, "dark_modern") orelse return error.UnknownTheme;
     conf.theme = theme_.name;