fix: delete backdrop renderer on invalidated by caixr23 · Pull Request #740 · linuxdeepin/dtkdeclarative

caixr23 · 2026-10-29T06:50:20Z

RhiManager now connects to QSGRenderContext::invalidated (DirectConnection) and destroys the Renderer immediately in destroyRenderer(), rather than waiting until RhiManager's destructor runs during QObject child cleanup.
Renderer holds a reference to QSGRenderContext's ShaderManager child; deleting the renderer after that child is gone causes a SIGSEGV in ~Renderer -> ShaderManager::clearCachedRendererData. Handling invalidated matches Qt's QSGRhiLayer pattern.
sync(), preprocess(), and render() now bail out when renderer (or m_rhi in preprocess) is null, preventing operations on a destroyed RHI context.
context/renderer are initialized to nullptr in the constructor, and destroyRenderer() is reused from both invalidated and ~RhiManager.
Added regression test destroyWithBackdropNodeOnRhi, which renders a frame with DQuickBackdropBlitter then destroys the window; it crashed before this fix and exits cleanly after.

Log: Fixed exit crash caused by DBackdropBlitter renderer lifecycle

Influence:

Close windows in existing InWindowBlur demos/apps and confirm no crash on the default RHI rendering path.
Run related scenes with the software scene graph backend to confirm the guards preserve behavior when RhiManager is not created.
On Qt6, exercise window teardown with OpenGL/Vulkan/D3D/Metal RHI backends, with and without DTK_DISABLE_INWINDOWBLUR.
Run the new regression test ut_DQuickInWindowBlur.destroyWithBackdropNodeOnRhi and verify it passes.

fix: 在 invalidated 时销毁 backdrop renderer

RhiManager 现在以直连连接监听 QSGRenderContext::invalidated，在信号发出时立即通过 destroyRenderer() 销毁 Renderer，不再等到 RhiManager 析构（QObject 子对象清理阶段）才执行。
Renderer 持有 QSGRenderContext 的 QObject 子对象 ShaderManager 的引用；在 ShaderManager 销毁后才 delete Renderer，会在 ~Renderer → ShaderManager::clearCachedRendererData 中访问已释放内存并崩溃。Qt 对 QSGRhiLayer 也是同样处理。
sync()、preprocess()、render() 在 renderer（preprocess 中还包含 m_rhi）为空时直接返回，避免在已销毁的 RHI context 上继续渲染。
构造函数将 context/renderer 初始化为 nullptr，删除逻辑集中到 destroyRenderer()，析构函数也调用它。
新增回归用例 destroyWithBackdropNodeOnRhi：先通过 DQuickBackdropBlitter 渲染一帧再销毁窗口；修复前会崩溃，修复后可正常
退出。

Log: 修复 DBackdropBlitter 渲染器生命周期导致的退出崩溃

Influence:

运行已有的 InWindowBlur 示例/应用并关闭窗口，确认默认 RHI 渲染路径不崩溃。
使用软件场景图后端运行相关场景，确认未创建 RhiManager 时保护逻辑不影响原有行为。
在 Qt6 下分别使用 OpenGL/Vulkan/D3D/Metal RHI 后端测试窗口销毁，并分别设置/不设置 DTK_DISABLE_INWINDOWBLUR。
运行新增回归用例 ut_DQuickInWindowBlur.destroyWithBackdropNodeOnRhi，确认通过。

PMS: TASK-397773

Summary by Sourcery

Fix backdrop renderer teardown so windows close safely after RHI rendering contexts are invalidated.

Bug Fixes:

Prevent exit-time crashes by destroying the backdrop renderer when the QSG render context is invalidated.
Guard rendering operations against missing renderer or RHI state after context invalidation.

Enhancements:

Centralize renderer cleanup and initialize RHI manager state safely.

Tests:

Add a Qt 6 regression test covering window destruction after an RHI backdrop frame has rendered.

sourcery-ai · 2026-10-29T08:07:47Z

Reviewer's Guide

The PR fixes an exit-time SIGSEGV by deleting the backdrop renderer synchronously when QSGRenderContext is invalidated, before its ShaderManager child is destroyed, and adds null guards plus a regression test for RHI window teardown.

Sequence diagram for safe RHI renderer teardown

sequenceDiagram
    participant Window as QQuickWindow
    participant Context as QSGRenderContext
    participant Manager as RhiManager
    participant Renderer as Renderer
    participant Shader as ShaderManager

    Window->>Context: invalidated()
    Context-->>Manager: destroyRenderer()
    Manager->>Renderer: delete renderer
    Renderer->>Shader: clearCachedRendererData()
    Context->>Shader: destroy ShaderManager
    Window->>Manager: ~RhiManager()
    Manager->>Manager: destroyRenderer()

Flow diagram for renderer invalidation guards

flowchart LR
    A[QSGRenderContext invalidated] --> B["destroyRenderer()"]
    B --> C["renderer = nullptr"]
    C --> D{sync, preprocess, or render}
    D -->|renderer or m_rhi unavailable| E[Return without rendering]
    D -->|resources available| F[Continue RHI rendering]

File-Level Changes

Change	Details	Files
Align the backdrop renderer lifetime with QSGRenderContext invalidation to avoid teardown-order crashes.	Initialize context and renderer safely. Connect invalidated with a direct connection to destroy the renderer immediately. Centralize cleanup in destroyRenderer() and reuse it during destruction. Guard synchronization and rendering paths after renderer or RHI invalidation.	`src/private/dbackdropnode.cpp`
Add a regression test covering RHI backdrop teardown after a completed render frame.	Render a BackdropBlitter frame before destroying the window. Skip environments without an applicable RHI or enabled InWindowBlur path. Verify window teardown completes without the prior renderer/ShaderManager crash.	`tests/ut_dquickinwindowblur.cpp`

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sourcery-ai

Hey - I've found 1 issue

Prompt for AI Agents

Please address the comments from this code review:

## Individual Comments

### Comment 1
<location path="src/private/dbackdropnode.cpp" line_range="385-386" />
<code_context>
     }

     bool preprocess(QRhiRenderTarget *rt, qreal &oldDPR, QRhiCommandBuffer* &oldCB, QSurface *forceSurface = nullptr) {
+        if (Q_UNLIKELY(!renderer || !m_rhi))
+            return false;
+
         QRhiCommandBuffer *cb = nullptr;
</code_context>
<issue_to_address>
**Rendering crashes without an RHI**

When `QSGRhiSupport::createRhi()` returns no RHI during initialization or resource exhaustion, `preprocess()` returns false, but `RhiNode::render()` continues to access `RhiManager::rhi()` or `this->rhi->rhi()` with a null RHI, crashing the render thread and the app.

Make `RhiNode::render()` stop before accessing the manager’s RHI when no RHI was created.
</issue_to_address>

Sourcery is free for open source - if you like our reviews please consider sharing them ✨

sourcery-ai · 2026-10-29T08:12:35Z

+        if (Q_UNLIKELY(!renderer || !m_rhi))
+            return false;


🟡 Medium · Rendering crashes without an RHI

When QSGRhiSupport::createRhi() returns no RHI during initialization or resource exhaustion, preprocess() returns false, but RhiNode::render() continues to access RhiManager::rhi() or this->rhi->rhi() with a null RHI, crashing the render thread and the app.

Make RhiNode::render() stop before accessing the manager’s RHI when no RHI was created.

Prompt for AI agents

In `src/private/dbackdropnode.cpp` at lines 385-386: **Rendering crashes without an RHI** When `QSGRhiSupport::createRhi()` returns no RHI during initialization or resource exhaustion, `preprocess()` returns false, but `RhiNode::render()` continues to access `RhiManager::rhi()` or `this->rhi->rhi()` with a null RHI, crashing the render thread and the app. Make `RhiNode::render()` stop before accessing the manager’s RHI when no RHI was created.

1. RhiManager now connects to QSGRenderContext::invalidated (DirectConnection) and destroys the Renderer immediately in destroyRenderer(), rather than waiting until RhiManager's destructor runs during QObject child cleanup. 2. Renderer holds a reference to QSGRenderContext's ShaderManager child; deleting the renderer after that child is gone causes a SIGSEGV in ~Renderer -> ShaderManager::clearCachedRendererData. Handling invalidated matches Qt's QSGRhiLayer pattern. 3. sync(), preprocess(), and render() now bail out when renderer (or m_rhi in preprocess) is null, preventing operations on a destroyed RHI context. 4. context/renderer are initialized to nullptr in the constructor, and destroyRenderer() is reused from both invalidated and ~RhiManager. 5. Added regression test destroyWithBackdropNodeOnRhi, which renders a frame with DQuickBackdropBlitter then destroys the window; it crashed before this fix and exits cleanly after. Log: Fixed exit crash caused by DBackdropBlitter renderer lifecycle Influence: 1. Close windows in existing InWindowBlur demos/apps and confirm no crash on the default RHI rendering path. 2. Run related scenes with the software scene graph backend to confirm the guards preserve behavior when RhiManager is not created. 3. On Qt6, exercise window teardown with OpenGL/Vulkan/D3D/Metal RHI backends, with and without DTK_DISABLE_INWINDOWBLUR. 4. Run the new regression test ut_DQuickInWindowBlur.destroyWithBackdropNodeOnRhi and verify it passes. fix: 在 invalidated 时销毁 backdrop renderer 1. RhiManager 现在以直连连接监听 QSGRenderContext::invalidated，在信号发出时立即通过 destroyRenderer() 销毁 Renderer，不再等到 RhiManager 析构（QObject 子对象清理阶段）才执行。 2. Renderer 持有 QSGRenderContext 的 QObject 子对象 ShaderManager 的引用；在 ShaderManager 销毁后才 delete Renderer，会在 ~Renderer → ShaderManager::clearCachedRendererData 中访问已释放内存并崩溃。Qt 对 QSGRhiLayer 也是同样处理。 3. sync()、preprocess()、render() 在 renderer（preprocess 中还包含 m_rhi）为空时直接返回，避免在已销毁的 RHI context 上继续渲染。 4. 构造函数将 context/renderer 初始化为 nullptr，删除逻辑集中到 destroyRenderer()，析构函数也调用它。 5. 新增回归用例 destroyWithBackdropNodeOnRhi：先通过 DQuickBackdropBlitter 渲染一帧再销毁窗口；修复前会崩溃，修复后可正常退出。 Log: 修复 DBackdropBlitter 渲染器生命周期导致的退出崩溃 Influence: 1. 运行已有的 InWindowBlur 示例/应用并关闭窗口，确认默认 RHI 渲染路径不崩溃。 2. 使用软件场景图后端运行相关场景，确认未创建 RhiManager 时保护逻辑不影响原有行为。 3. 在 Qt6 下分别使用 OpenGL/Vulkan/D3D/Metal RHI 后端测试窗口销毁，并分别设置/不设置 DTK_DISABLE_INWINDOWBLUR。 4. 运行新增回归用例 ut_DQuickInWindowBlur.destroyWithBackdropNodeOnRhi，确认通过。 PMS: TASK-397773

deepin-ci-robot · 2026-10-29T09:49:13Z

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🤖 AI 代码审查报告

总体评分： 100 分 (通过阈值: 70分)

📊 总体评价

项目	结果
审查结论	代码审查通过
评分详情	本次提交修复了窗口销毁时 RhiManager 的 renderer 因在 QObject 子对象清理阶段才被 delete，导致 ~Renderer 访问已释放的 ShaderManager 而引发 SIGSEGV 的崩溃问题。修复方案正确地将 renderer 的销毁时机提前到 QSGRenderContext::invalidated 信号触发时，并在 sync/preprocess/render 三个方法中增加空指针保护。四维度分析均未发现问题，代码注释详尽，测试用例覆盖完整，无安全漏洞。

🔍 详细分析

1. 语法逻辑 ✅

评价： 语法正确，逻辑清晰 ✅ 通过

潜在问题：
✅ 未发现明显问题

建议： ['无需修改，语法逻辑完全正确。']

2. 代码质量 ✅

评价： 代码结构清晰，注释完整 ✅ 通过

潜在问题：
✅ 未发现明显问题

建议： ['无需修改，代码质量和注释完整度均达标。']

3. 代码性能 ✅

评价： 性能良好，资源使用合理 ✅ 通过

潜在问题：
✅ 未发现明显问题

建议： ['无需修改，性能表现良好。']

4. 代码安全 🔒

评价： 存在0个安全漏洞 ✅ 通过

🔐 发现 0 个安全漏洞

安全漏洞详情：
✅ 未发现安全漏洞

建议： ['无需修改，代码安全合规。']

💡 改进建议代码示例

// 当前代码已正确修复了生命周期问题，无需额外修改。
// 核心修复模式如下（已存在于提交中）：
//
// 在 RhiManager 构造函数中连接 invalidated 信号：
//   connect(context, &QSGRenderContext::invalidated,
//           this, &RhiManager::destroyRenderer, Qt::DirectConnection);
//
// 在 sync/preprocess/render 中增加空指针保护：
//   if (Q_UNLIKELY(!renderer))
//       return;
//
// destroyRenderer() 方法确保原子销毁：
//   void destroyRenderer() {
//       delete renderer;
//       renderer = nullptr;
//   }

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deepin-ci-robot · 2026-10-29T11:07:54Z

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: 18202781743, caixr23

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caixr23 · 2026-10-30T01:32:48Z

/merge

deepin-bot · 2026-10-30T01:33:07Z

This pr cannot be merged! (status: unstable)

caixr23 · 2026-10-30T01:43:42Z

/forcemerge

deepin-bot · 2026-10-30T01:43:55Z

This pr force merged! (status: unstable)

caixr23 force-pushed the master branch from 576c907 to 12127ec Compare October 29, 2026 06:52

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Comment thread tests/ut_dquickinwindowblur.cpp Outdated

caixr23 dismissed 18202781743’s stale review via 098f062 October 29, 2026 07:54

caixr23 force-pushed the master branch from 12127ec to 098f062 Compare October 29, 2026 07:54

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caixr23 dismissed 18202781743’s stale review via 621150a October 29, 2026 09:42

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deepin-bot Bot merged commit 0159003 into linuxdeepin:master Oct 30, 2026
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fix: delete backdrop renderer on invalidated - #740

fix: delete backdrop renderer on invalidated#740
deepin-bot[bot] merged 1 commit into
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Reviewer's Guide

Sequence diagram for safe RHI renderer teardown

Flow diagram for renderer invalidation guards

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