fix: add ThreadLocal reentrancy guard to SpyImpl to prevent recursive advice dispatch#3161
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fix: add ThreadLocal reentrancy guard to SpyImpl to prevent recursive advice dispatch#3161daguimu wants to merge 2 commits intoalibaba:masterfrom
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… advice dispatch When watching a toString() method, Arthas's own ObjectView.renderObject() calls toString() on the watched object to display results. This triggers the advice listener again on the same thread, causing infinite recursion. Fix by adding a ThreadLocal<Boolean> DISPATCHING guard to SpyImpl. When already dispatching advice on the current thread, re-entrant calls from the same thread are skipped, preventing recursion. Applies guard to atEnter(), atExit(), and atExceptionExit(). Zero overhead on non-recursive paths (single ThreadLocal read). Fixes alibaba#3083
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…thod coverage - Add debug logging when reentrancy is detected for easier troubleshooting - Extend DISPATCHING guard to trace invoke methods (atBeforeInvoke, atAfterInvoke, atInvokeException) which have the same recursive dispatch risk Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Problem
When using
watchto intercept atoString()method, Arthas's own output rendering code (ObjectView.renderObject()) callstoString()on the watched object to display results. This call re-triggers the advice listener on the same thread, causing infinite recursion.Steps to reproduce:
If
MyClass.toString()is called by Arthas's rendering pipeline, it re-fires the watch, which renders again, which callstoString()again — infinite loop.Root Cause
SpyImpl.atEnter/atExit/atExceptionExithad no guard against re-entrant calls on the same thread.Fix
Add a
ThreadLocal<Boolean> DISPATCHINGguard toSpyImpl. Before dispatching advice listeners, check if we are already dispatching on the current thread. If so, return early to break the re-entrancy cycle.The guard is reset in a
finallyblock to ensure correctness even if an exception occurs during dispatch.Impact
atEnter,atExit,atExceptionExitare guarded; trace invoke methods are unaffectedFixes #3083