fix(v3/linux): use g_bytes_new instead of g_bytes_new_static for Go slices by ddmoney420 · Pull Request #4923 · wailsapp/wails

ddmoney420 · 2026-01-29T07:49:02Z

Summary

Replace g_bytes_new_static with g_bytes_new for all Go slice data
Fix memory leak in setIcon() by adding proper cleanup
Add gBytesNew binding to purego implementation

Problem

g_bytes_new_static is documented as expecting "static" data that is never freed or moved. However, the Linux code was passing Go slice data (&icon[0], &img.Pix[0]) which can be moved or freed by Go's garbage collector at any time.

When Go's GC runs, the memory passed to GTK becomes invalid, causing a SIGSEGV crash in g_application_run (the GTK event loop).

From the GLib docs:

g_bytes_new_static: Creates a new GBytes from static data. data must be static (ie: never modified or freed).

Solution

Use g_bytes_new instead, which copies the data to C-owned memory that is safe from Go's GC.

// Before (unsafe - Go memory can be GC'd)
gbytes := C.g_bytes_new_static(C.gconstpointer(unsafe.Pointer(&icon[0])), ...)

// After (safe - data is copied to C memory)
gbytes := C.g_bytes_new(C.gconstpointer(unsafe.Pointer(&icon[0])), ...)

Changes

File	Change
`linux_cgo.go`	Replace `g_bytes_new_static` → `g_bytes_new` (4 places)
`linux_cgo.go`	Add `defer C.g_bytes_unref(gbytes)` and `defer C.g_object_unref(stream)` in `setIcon()`
`linux_purego.go`	Add `gBytesNew` function binding
`linux_purego.go`	Replace `gBytesNewStatic` → `gBytesNew`

Test plan

Code compiles on macOS (build tags prevent Linux code from compiling)
Manual test on Linux with array parameters

Note: The correlation with "array parameters" in the original issue is likely because array-heavy operations increase memory pressure, triggering GC more frequently and exposing this race condition faster.

Fixes #4864

🤖 Generated with Claude Code

Summary by CodeRabbit

Bug Fixes
- Fixed potential crash when focusing a destroyed window on Linux.
- Prevented a panic when an empty icon/bitmap is provided on Linux.
Improvements
- Improved memory and resource handling for graphics on Linux, enhancing stability and preventing memory-related issues with icons and images.

The Focus() method was missing a nil/destroyed check on w.impl, causing a SIGSEGV when Focus() is called on a window that has been hidden and potentially destroyed (e.g., when clicking the dock icon after hiding the window on macOS). This aligns Focus() with Show() and Hide() which already have proper guards against nil/destroyed window implementations. Fixes wailsapp#4890 Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

…lices g_bytes_new_static expects truly static data that is never freed or moved, but Go's garbage collector can move or free slice memory at any time. This causes SIGSEGV crashes in the GTK event loop when the GC runs and frees memory that GTK still references. The fix replaces g_bytes_new_static with g_bytes_new, which copies the data to C-owned memory that is safe from Go's GC. Also fixes memory leak in setIcon() by adding proper g_bytes_unref and g_object_unref calls for the GBytes and stream objects. Changes: - linux_cgo.go: Replace g_bytes_new_static with g_bytes_new (4 places) - linux_cgo.go: Add cleanup in setIcon() for gbytes and stream - linux_purego.go: Add gBytesNew binding and use it instead of static Fixes wailsapp#4864 Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

coderabbitai · 2026-01-29T07:49:38Z

Walkthrough

Replaced static GBytes usage with dynamic GBytes allocations and added explicit unref/defer calls to ensure C memory isn't tied to Go GC; added guards to avoid creating bytes for empty images; registered a new gBytesNew pointer in pure-Go path; added a nil/destroyed check in WebviewWindow.Focus; updated changelog.

Changes

Cohort / File(s)	Summary
GBytes memory & icon handling `v3/pkg/application/linux_cgo.go`, `v3/pkg/application/linux_purego.go`	Replaced `g_bytes_new_static(...)` usage with `g_bytes_new(...)` (explicit copy) and added `defer C.g_bytes_unref(...)` and `defer C.g_object_unref(...)`. Added guards to skip icon/bitmap handling when image data is empty and registered `gBytesNew` in the pure-Go GTK function table.
Window focus safety `v3/pkg/application/webview_window.go`	Added an early return in `WebviewWindow.Focus()` when the underlying implementation is nil or the window is destroyed to avoid potential panics.
Changelog `v3/UNRELEASED_CHANGELOG.md`	Added a bugfix entry noting a potential panic when setting an empty icon/bitmap on Linux.

Sequence Diagram(s)

(Skipped — changes are internal memory-management and small control checks that do not introduce a new multi-component sequential flow.)

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Suggested labels

go, Linux, v3-alpha

Poem

A rabbit nibbles bytes with care,
Copies saved from GC's snare,
Defer a hop, unref the trail,
Empty icons now skip the tale,
Safe and snug — a hopping cheer! 🐰

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Description check	❓ Inconclusive	The PR description provides a clear summary, explains the problem and solution, lists file changes, and references the linked issue. However, the description template requires specific sections (Type of change checkboxes, How Has This Been Tested, Test Configuration) that are not completed.	Complete the PR template sections: check the 'Bug fix' option under Type of change, describe testing performed on Linux, and provide wails doctor output or environment details.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately summarizes the primary change: replacing g_bytes_new_static with g_bytes_new for Go slices to fix memory safety issues on Linux.
Linked Issues check	✅ Passed	The PR addresses the root cause of issue `#4864` by replacing g_bytes_new_static with g_bytes_new to copy Go slice data to C-owned memory, preventing GC-related SIGSEGV crashes during GTK event loop execution.
Out of Scope Changes check	✅ Passed	Changes are focused on the memory safety issue and include defensive nil check in WebviewWindow.Focus and changelog update, both of which align with the PR objectives.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

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coderabbitai

Actionable comments posted: 2

🤖 Fix all issues with AI agents

In `@v3/pkg/application/linux_cgo.go`:
- Around line 665-669: The code takes &slice[0] on icon/bitmap byte slices
(e.g., in linuxApp.setIcon) which will panic for zero-length slices; add a guard
that checks len(icon)==0 (or len(bitmap)==0) and return early (no-op) or handle
as an empty icon before taking &icon[0]; apply the same pattern to the other
similar functions referenced (the blocks at the other occurrences) so you never
call C.g_bytes_new with &slice[0] when the slice is empty.

In `@v3/pkg/application/linux_purego.go`:
- Around line 1196-1200: The code calls
gBytesNew(uintptr(unsafe.Pointer(&img.Pix[0])), len(img.Pix)) without checking
for an empty img.Pix, which can panic; before taking &img.Pix[0] in the
pngToImage success branch, add a guard like if len(img.Pix) == 0 { /* handle
empty icon: skip gBytesNew / set gbytes=nil / use empty buffer */ } else {
gbytes := gBytesNew(uintptr(unsafe.Pointer(&img.Pix[0])), len(img.Pix)) ... } so
pngToImage, img.Pix, and gBytesNew are only used when img.Pix has length > 0.

Adds guards to check for empty slices before taking &slice[0] which would panic on empty input. Affects setIcon(), menuItemAddProperties(), menuItemSetBitmap(), and runQuestionDialog() in both CGO and purego. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

coderabbitai

Actionable comments posted: 0

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

v3/pkg/application/linux_cgo.go (1)
841-858: ⚠️ Potential issue | 🟡 Minor

Unref the temporary GdkPixbuf after creating the GtkImage.
gtk_image_new_from_pixbuf() adds its own reference and does not take ownership, so the local pixBuf must be unref'd to avoid memory leaks. Apply in these three locations.
♻️ Proposed fix (apply to each site)
 pixBuf := C.gdk_pixbuf_new_from_bytes(
 	gbytes,
 	C.GDK_COLORSPACE_RGB,
 	1, // has_alpha
 	8,
 	C.int(img.Bounds().Dx()),
 	C.int(img.Bounds().Dy()),
 	C.int(img.Stride),
 )
 image := C.gtk_image_new_from_pixbuf(pixBuf)
+C.g_object_unref(C.gpointer(pixBuf))
 C.gtk_widget_set_visible((*C.GtkWidget)(image), C.gboolean(1))
Also applies to: 923-940, 2205-2223

sonarqubecloud · 2026-02-02T08:42:48Z

Quality Gate failed

Failed conditions
27.6% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud

…lices (wailsapp#4923) * fix(v3): add nil check to Focus() to prevent SIGSEGV after Hide The Focus() method was missing a nil/destroyed check on w.impl, causing a SIGSEGV when Focus() is called on a window that has been hidden and potentially destroyed (e.g., when clicking the dock icon after hiding the window on macOS). This aligns Focus() with Show() and Hide() which already have proper guards against nil/destroyed window implementations. Fixes wailsapp#4890 Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com> * fix(v3/linux): use g_bytes_new instead of g_bytes_new_static for Go slices g_bytes_new_static expects truly static data that is never freed or moved, but Go's garbage collector can move or free slice memory at any time. This causes SIGSEGV crashes in the GTK event loop when the GC runs and frees memory that GTK still references. The fix replaces g_bytes_new_static with g_bytes_new, which copies the data to C-owned memory that is safe from Go's GC. Also fixes memory leak in setIcon() by adding proper g_bytes_unref and g_object_unref calls for the GBytes and stream objects. Changes: - linux_cgo.go: Replace g_bytes_new_static with g_bytes_new (4 places) - linux_cgo.go: Add cleanup in setIcon() for gbytes and stream - linux_purego.go: Add gBytesNew binding and use it instead of static Fixes wailsapp#4864 Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com> * fix(linux): add empty slice guards to prevent panic Adds guards to check for empty slices before taking &slice[0] which would panic on empty input. Affects setIcon(), menuItemAddProperties(), menuItemSetBitmap(), and runQuestionDialog() in both CGO and purego. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com> --------- Co-authored-by: ddmoney420 <ddmoney420@users.noreply.github.com> Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com> Co-authored-by: Lea Anthony <lea.anthony@gmail.com>

ddmoney420 and others added 2 commits January 29, 2026 00:38

coderabbitai Bot reviewed Jan 29, 2026

View reviewed changes

Comment thread v3/pkg/application/linux_cgo.go

Comment thread v3/pkg/application/linux_purego.go Outdated

leaanthony approved these changes Feb 2, 2026

View reviewed changes

Merge branch 'v3-alpha' into fix/4864-gbytes-gc-safety

55086f5

leaanthony enabled auto-merge (squash) February 2, 2026 07:44

coderabbitai Bot reviewed Feb 2, 2026

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leaanthony merged commit 19b2ec7 into wailsapp:v3-alpha Feb 2, 2026
47 of 48 checks passed

coderabbitai Bot mentioned this pull request Feb 2, 2026

fix(v3): add nil check to Focus() to prevent SIGSEGV after Hide #4922

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coderabbitai Bot mentioned this pull request May 5, 2026

fix(linux): split dialog dispatch between GTK3 and GTK4 #5340

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coderabbitai Bot mentioned this pull request May 21, 2026

fix(linux): implement setAlwaysOnTop + fix SoupMessageHeaders leak (GTK4 + GTK3) #5488

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fix(v3/linux): use g_bytes_new instead of g_bytes_new_static for Go slices#4923

fix(v3/linux): use g_bytes_new instead of g_bytes_new_static for Go slices#4923
leaanthony merged 4 commits into
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ddmoney420:fix/4864-gbytes-gc-safety

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