Debug config crashing

[milhauzindahauz]

Description

I am trying to debug wails app. App is freshly initialized. When I put the breakpoint inside Greet function the app crashes.

To Reproduce

1. wails init -n voice_key -t svelte -ide vscode
2. cd frontend && npm install && npm run build && cd -
3. code .
4. run Wails: Debug launch options

Expected behaviour

App is not crashing. Breakpoint is triggered.

Screenshots

Attempted Fixes

No response

System Details

# Wails
Version         | v2.10.1
Package Manager | dnf    


# System
WARNING: failed to read int from file: open /sys/devices/system/cpu/cpu0/online: no such file or directory
┌───────────────────────────────────────────────────────────────────────────────────┐
| OS           | Fedora Linux                                                       |
| Version      | 42                                                                 |
| ID           | fedora                                                             |
| Go Version   | go1.24.4                                                           |
| Platform     | linux                                                              |
| Architecture | amd64                                                              |
| CPU          | AMD Ryzen 7 PRO 7840HS w/ Radeon 780M Graphics                     |
| GPU          | Phoenix1 (Advanced Micro Devices, Inc. [AMD/ATI]) - Driver: amdgpu |
| Memory       | 64GB                                                               |
└───────────────────────────────────────────────────────────────────────────────────┘

# Dependencies
┌────────────────────────────────────────────────────────┐
| Dependency | Package Name        | Status    | Version |
| *docker    | moby-engine         | Installed | 28.3.0  |
| gcc        | gcc-c++             | Installed | 15.0.1  |
| libgtk-3   | gtk3-devel          | Installed | 3.24.49 |
| libwebkit  | webkit2gtk4.0-devel | Installed | 2.47.2  |
| npm        | nodejs-npm          | Installed | 10.9.2  |
| pkg-config | pkgconf-pkg-config  | Installed | 2.3.0   |
| *upx       | upx                 | Installed | 5.0.1   |
|                                                        |
└─────────────── * - Optional Dependency ────────────────┘

Additional context

I am a little skeptical about wails doctor because it marked everythink as ok. But dependency was missing.

[dosubot]

Hi @milhauzindahauz! I'm Dosu and I’m helping the wails team.

There are no known open issues or docs that directly address Wails v2.10.1 crashing at breakpoints on Fedora, but the codebase and changelog show that Wails uses custom signal and process management on Linux, which can interfere with Delve (the Go debugger) and cause instability when hitting breakpoints—especially if signals are handled differently than Delve expects (source). Recent Wails releases improved Linux signal handling (PR #2152), and Fedora-specific dependency checks were added (PR #2218), so make sure all dependencies are present.

Try running your app under Delve manually (e.g., dlv exec ./build/bin/yourapp) to see if the crash is specific to VSCode integration. If it still crashes, it's likely a Delve/Wails/Linux interaction. If it works, the issue may be with the VSCode debug config—double-check that your .vscode/launch.json uses "mode": "exec" and that your build task includes -gcflags "all=-N -l" for debugging.

If you can, share any error messages or stack traces from the debug console when the crash happens. This will help pinpoint if the crash is due to signal handling, process management, or something else. If the problem persists, try debugging a minimal Go app (without Wails) to rule out a broader Delve/Fedora issue.

To reply, just mention @dosu.

---

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[leaanthony]

@milhauzindahauz - A PR has been made that might fix this but what would be helpful is if you provided the stack trace

[leaanthony]

After investigation, we've determined that the signal handler fixup (install_signal_handlers()) is necessary for proper Go/WebKit interop (see #2134 for history). Disabling it would re-introduce crashes on panics.

Workaround for Debugging with Delve

If you need to debug with Delve on Linux and are experiencing issues, you can manually reset signal handlers before potentially crashing code:

// +build linux

package main

/*
#include <signal.h>
#include <errno.h>
#include <string.h>

static void reset_signal_handler(int signum) {
    struct sigaction sa;
    if (sigaction(signum, NULL, &sa) == -1) {
        return;
    }
    sa.sa_flags |= SA_ONSTACK;
    sigaction(signum, &sa, NULL);
}

void ResetSignalHandlers() {
    reset_signal_handler(SIGSEGV);
    reset_signal_handler(SIGBUS);
    reset_signal_handler(SIGFPE);
    reset_signal_handler(SIGABRT);
}
*/
import "C"

// Call this before code that might panic when debugging
func ResetSignalHandlers() {
    C.ResetSignalHandlers()
}

Then in your debug code:

func riskyOperation() {
    ResetSignalHandlers() // Call immediately before risky code
    // ... code that might panic
}

Note: This is a fundamental Go/C interop limitation (see golang/go#7227). The signal handlers may be reset by WebKit at any time, so you may need to call this repeatedly.

For most users, the automatic signal handler fixup in Wails works correctly. This manual approach is only needed for specific debugging scenarios.

[leaanthony]

Update: PR #4921 has been merged which adds runtime.ResetSignalHandlers() to v2.

For debugging with Delve on Linux, you can now use:

import "github.com/wailsapp/wails/v2/pkg/runtime"

func riskyOperation(ctx context.Context) {
    runtime.ResetSignalHandlers()  // Call before potentially panicking code
    // ... your code
}

This is simpler than the manual CGO approach in my previous comment.