LeakCanary无法找到保留对象的路径

Question

在使用LeakCanary搜索应用程序中的内存泄漏时，我偶然发现了一个奇怪的结果：

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这是Logcat中有趣的部分：

D/LeakCanary: Found 9 objects retained, dumping heap now (app is visible & >=5 threshold)
D/LeakCanary: WRITE_EXTERNAL_STORAGE permission not granted, ignoring
D/LeakCanary: Setting up flushing for Thread[LOCATION,5,main]
D/LeakCanary: Analysis in progress, working on: PARSING_HEAP_DUMP
D/LeakCanary: Analysis in progress, working on: EXTRACTING_METADATA
D/LeakCanary: Analysis in progress, working on: FINDING_RETAINED_OBJECTS
D/LeakCanary: Setting up flushing for Thread[IntentService[HeapAnalyzerService],5,main]
D/LeakCanary: Analysis in progress, working on: FINDING_PATHS_TO_RETAINED_OBJECTS
D/LeakCanary: Found 25 retained objects
D/LeakCanary: Found 0 paths to retained objects
D/LeakCanary: Analysis in progress, working on: INSPECTING_OBJECTS
D/LeakCanary: Analysis in progress, working on: COMPUTING_NATIVE_RETAINED_SIZE
D/LeakCanary: Analysis in progress, working on: COMPUTING_RETAINED_SIZE
D/LeakCanary: Analysis in progress, working on: BUILDING_LEAK_TRACES
D/LeakCanary: Analysis in progress, working on: REPORTING_HEAP_ANALYSIS
D/LeakCanary: ​
    ====================================
    HEAP ANALYSIS RESULT
    ====================================
    0 APPLICATION LEAKS
    
    References underlined with "~~~" are likely causes.
    Learn more at https://squ.re/leaks.
    ====================================
    0 LIBRARY LEAKS
    
    A Library Leak is a leak caused by a known bug in 3rd party code that you do not have control over.
    See https://square.github.io/leakcanary/fundamentals-how-leakcanary-works/#4-categorizing-leaks
    ====================================
    METADATA
    
    Please include this in bug reports and Stack Overflow questions.
    
    Build.VERSION.SDK_INT: 29
    Build.MANUFACTURER: samsung
    LeakCanary version: 2.5
    App process name: 
    Stats: LruCache[maxSize=3000,hits=7157,misses=65789,hitRate=9%]
    RandomAccess[bytes=3638897,reads=65789,travel=66202063325,range=23021778,size=54136938]
    Analysis duration: 17316 ms
    Heap dump file path: 
    Heap dump timestamp: 1605711733381
    Heap dump duration: 1506 ms
    ====================================

看起来leakcanary无法获取路径，这很奇怪...是否有其他方法可以查看保留的对象？

Answer 1

LeakCanary导航对象图，从所有GC根(例如静态字段)和以下引用开始。这个结果意味着LeakCanary没有找到导致实例泄漏的路径。

LeakCanary只遵循强引用而忽略弱引用，因为这些引用不应该阻止对象被垃圾收集。你可以在这里看到被忽略的引用列表：https://github.com/square/leakcanary/blob/main/shark-android/src/main/java/shark/AndroidReferenceMatchers.kt#L1159-L1236

您可以做的一件事是定制该列表，删除一些条目。请记住，LeakCanary只提供最短路径，因此可能有几条路径通过被忽略的引用。

否则，您可以使用Eclipse MAT (免费)或YourKit (最好的工具，但不是免费的)：https://square.github.io/leakcanary/faq/#how-can-i-dig-beyond-the-leak-trace

另一种选择是提取堆转储，然后编写一个小的Kotlin脚本来运行分析并调整配置，直到找到您想要的：https://square.github.io/leakcanary/shark/#generating-a-heap-analysis-report