TomMD commented on a change in pull request #6103:
URL: https://github.com/apache/skywalking/pull/6103#discussion_r550234070
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File path:
apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/plugin/WitnessClassFinder.java
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@@ -36,6 +36,17 @@
* @return true, if the given witnessClass exists, through the given
classLoader.
*/
public boolean exist(String witnessClass, ClassLoader classLoader) {
+ return getResolution(witnessClass, classLoader)
Review comment:
@wu-sheng I haven't looked at the actual trace produced by the tool but
here are my thoughts - please let me know if they seem off and I can ask the
tool for its explanation.
The message here is due to the same core issue as you see in the
`getResolution` comment below. When calling `getResolution` then without
synchronization we execute:
```
TypePool typePool = poolMap.get(mappingKey);
```
And that can race with a write to `poolMap` occurring in another thread.
There might not be a `mappingKey` inside of `poolMap` because `poolMap` could
be modified prior to calling `get`. If you'd like to be sure the element
exists then you'd need the synchronize block to encompass both the `get` and
the `containsKey` call.
We're planning on making traces accessible from the comments with a commands
to the bot - this would illuminate the supposed bugs and help developers decide
if the trace is feasible and worth changing. We welcome any thoughts you have
about bug explanation and elaboration.
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