Mapping location after kotlin confusion

author ： Yugang said

Talk about this article kotlin Of mapping Location of documents , Take a specific online crash as an example

Online crash log

Caused by: java.lang.IndexOutOfBoundsException: toIndex = 10
at java.util.AbstractList.subListRangeCheck(AbstractList.java:507)
at java.util.ArrayList$SubList.subList(ArrayList.java:1238)
at b.a.a.a.p.y1.i(SearchRecordFragment.kt:12)
at b.a.a.a.p.f0.run(lambda:6)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:264)
at android.app.ActivityThread.main(ActivityThread.java:8306)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:632)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1049)

Through the crash log above , The specific crash code can be found here

at java.util.ArrayList$SubList.subList(ArrayList.java:1238)
at b.a.a.a.p.y1.i(SearchRecordFragment.kt:12)

here b.a.a.a.p.y1 Represents a class , final i Represents a method , Or variables , Here is actually a method , Because there is a call stack before and after , Here we call the sublist Crash caused by method , final kt:12 The number of lines after confusion is 12 That's ok

analysis mapping, Locate the specific code

Next , We turn on mapping file , Search for b.a.a.a.p.y1 This string , give the result as follows

Find the corresponding class mapping Information , The next step is to find i, You can find many in this class i Statement of , For example, the following , It's not what we're looking for i

//  This i It's a Lzay Variable of type 
kotlin.Lazy lateSearchRecordAdapter$delegate -> i
//  Ahead 3:4 The number of lines is wrong , What we are looking for is 12
3:4:void com.ygp.mro.app.search.adapter.SearchRecordAdapter.setShowExpandView(boolean):50:51 -> i

Keep looking , Found the final matching location , as follows

    11:11:java.util.List com.ygp.mro.app.search.adapter.SearchRecordAdapter.getData():22:22 -> i
    11:11:void initListShowExpand():185 -> i
    12:13:void initListShowExpand():185:186 -> i
    14:14:void com.ygp.mro.app.search.adapter.SearchRecordAdapter.setData(java.util.List):0:0 -> i
    14:14:void initListShowExpand():186 -> i

The middle line above , It's what we want 12:13:void initListShowExpand():185:186 -> i, After confusion 12:13 The corresponding real number of rows is 185:186, So the actual collapse is 185 That's ok

Look at the corresponding source code

The source code here also calls sublist Method , Consistent with the method called by the crash , So it was determined that it was here that caused the crash

Further verify

Through the source code with mapping, You can find , The way to collapse is initListShowExpand, Where is this method called ？ We did this by looking at , There are two places to call

When the concrete collapse , Where was it called , Look at the collapse log

at b.a.a.a.p.y1.i(SearchRecordFragment.kt:12)
at b.a.a.a.p.f0.run(lambda:6)
at android.os.Handler.handleCallback(Handler.java:938)

It's here b.a.a.a.p.f0 Of run Method , and run The way is handler Callback , Keep going mapping File search b.a.a.a.p.f0

Found a lot of run Call to , And there is this behind the method lambda:6, Let's find the corresponding 6 This place , eureka

6:6:void com.ygp.mro.app.search.SearchRecordFragment$initListener$2.onGlobalLayout$lambda-1(com.ygp.mro.app.search.SearchRecordFragment):151:151 -> run
    6:6:void com.ygp.mro.app.search.SearchRecordFragment$initListener$2.lambda$EpImLmOa5i7W3KU8Q9jIBuQ78Gk(com.ygp.mro.app.search.SearchRecordFragment):0 -> run
    6:6:void run():0 -> run

Corresponding to the source code 151 That's ok , View source code , Found the calling code

So the result is 151 Line call initListShowExpand Method , Then inside the method 185 The line crashed