Fixes a race bug #64
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Fixes a race bug #64
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…server quickly responds with result (which triggers updateResults to run) prior to the state machine being added to the list of machines. When this happens, the update results CB (which only runs once) per goal doesn't get to move the machine into DONE and it stays ACTIVE forever, despite the server actually sending a result and being SUCEEDED.
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@mikaelarguedas This is kind of a blocker for long-term, production level code, so I hope we can get it merged and pushed out into the rosbuild farm quickly. |
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Added Issue #66 that provides simple debug lines to reproduce the bug deterministically using simple test applications. |
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Thanks for the detailed issue and reproducible example, I'll test this soon. |
mikaelarguedas
approved these changes
Feb 14, 2017
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reproduced and validated locally. thanks @pbeeson for the fix!
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Fixes bug where client state machine never reaches DONE state.
Fix: client needs to send the goal to the server AFTER it sets up its state machine and adds that machine to the list_, which is looped over on callbacks from server messages.
The pre-patched code would send out a goal to the server before adding the state machine instance to the list_ data structure. Occasionally, if the server published back a result message prior to the state machine being added to the list, updateResults() would run, not see the state machine, so never transition the machine into the DONE state. It would stay stuck at ACTIVE forever, despite the server actually being not active/succeeded.
This happens rarely but I was able to make a setup to reproduce reasonably often by having a server setSucceeded() immediately, then max out my CPU and network until the client hung.