Run CompletableResultCode completion action outside the lock

[amit306]

Fixes #8771

Problem

CompletableResultCode#succeed and failInternal run completion actions while holding a lock. This can cause a deadlock if two actions try to complete each other. Also, if an action throws an exception, the remaining actions are skipped and the result may never complete.

Solution

Both methods now use a shared complete method. It updates the result and copies the actions while holding the lock, then releases the lock before running them. runActions logs each exception, continues running the remaining actions, and rethrows the first exception at the end. whenComplete also uses runActions when the result is already complete.

[codecov]

Codecov Report

❌ Patch coverage is 96.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 91.29%. Comparing base (c87b50e) to head (4afc49d).
⚠️ Report is 17 commits behind head on main.

Files with missing lines	Patch %	Lines
...pentelemetry/sdk/common/CompletableResultCode.java	96.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #8773   +/-   ##
=========================================
  Coverage     91.29%   91.29%           
- Complexity    10498    10523   +25     
=========================================
  Files          1006     1007    +1     
  Lines         28338    28397   +59     
  Branches       3581     3594   +13     
=========================================
+ Hits          25870    25926   +56     
- Misses         1675     1676    +1     
- Partials        793      795    +2     

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Waiting on reviewers · refreshed 2026-09-06 22:12 UTC

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[jack-berg]

Another option is to run all actions first and then throw the first exception. This would fix the issue while keeping the current behavior of succeed. Let me know your opinion.

We should do this, plus logging for all exceptions. Also, let's catch Exception, not Throwable. That will mean that errors (i.e. Throwables which are not Exceptions) bubble up and violate the "allOf" completion guarantee. But this seems fine and defensible.

Also, your PR description is too verbose. The key details are watered down by the noise of details like which specific test cases were added, which is self explanatory from the code. Less is more. I recommend writing PR descriptions/comments yourself, rather than relying on AI.

[amit306]

Another option is to run all actions first and then throw the first exception. This would fix the issue while keeping the current behavior of succeed. Let me know your opinion.

We should do this, plus logging for all exceptions. Also, let's catch Exception, not Throwable. That will mean that errors (i.e. Throwables which are not Exceptions) bubble up and violate the "allOf" completion guarantee. But this seems fine and defensible.

Also, your PR description is too verbose. The key details are watered down by the noise of details like which specific test cases were added, which is self explanatory from the code. Less is more. I recommend writing PR descriptions/comments yourself, rather than relying on AI.

thanks @jack-berg for comment. I updated the code and description. Please check