Fix memory leak on roadrunner/frankenphp/etc due to appsec telemetry

[cataphract]

Description

During "user request mode" (one of FrankenPHP's modes, roadrunner, etc.), the telemetry buffer would grow at constant rate of 300 bytes/req, never being drained, draining would only happen at rshutdown

Reviewer checklist

• Test coverage seems ok.
• Appropriate labels assigned.

[datadog-datadog-prod-us1]

 

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⚠️ Warnings

🚦 35 Pipeline jobs failed

DataDog/apm-reliability/dd-trace-php | PHP Language Tests: [7.1]     

🧪 2 Tests failed

All test failures are known flaky.

❄️ Known flaky: opendir-003.phpt - opendir() with 'ftps://' stream. from php-src.php-src.ext.standard.tests.streams  

002+ error:0A000086:SSL routines::certificate verify failed in /usr/local/src/php/ext/standard/tests/streams/opendir-003.php on line 10
003+ 
002-  in %s on line %d
007+ 
009+ error:0A000415:SSL routines::sslv3 alert certificate expired in /usr/local/src/php/ext/ftp/tests/server.inc on line 121
010+ SSLv23 handshake failed.

Not introduced in this PR.

❄️ Known flaky: opendir-004.phpt - opendir() with 'ftps://' stream. from php-src.php-src.ext.standard.tests.streams  

002+ error:0A000086:SSL routines::certificate verify failed in /usr/local/src/php/ext/standard/tests/streams/opendir-004.php on line 10
003+ 
005+ error:0A000415:SSL routines::sslv3 alert certificate expired in /usr/local/src/php/ext/ftp/tests/server.inc on line 121
006+ SSLv23 handshake failed.
007+ 
009+ bool(false)
010+ 
001- resource(%d) of type (stream)
002- string(5) "file1"
003- string(5) "file1"
...

Not introduced in this PR.

DataDog/apm-reliability/dd-trace-php | PHP Language Tests: [7.3]     

🧪 1 Test failed

All test failures are known flaky.

❄️ Known flaky: opendir() with 'ftps://' stream. from PHP.ext.standard.tests.streams  

002+ error:0A000086:SSL routines::certificate verify failed in /usr/local/src/php/ext/standard/tests/streams/opendir-004.php on line 10
003+ 
005+ bool(false)
006+ 
001- resource(%d) of type (stream)
002- string(5) "file1"
003- string(5) "file1"
004- string(3) "fil"
005- string(4) "b0rk"
009+ 
...

Not introduced in this PR.

DataDog/apm-reliability/dd-trace-php | PHP Language Tests: [8.0]     

🧪 2 Tests failed

All test failures are known flaky.

❄️ Known flaky: ext/standard/tests/streams/opendir-003.phpt (opendir() with 'ftps://' stream.) from PHP.ext.standard.tests.streams  

002+ error:0A000086:SSL routines::certificate verify failed in /usr/local/src/php/ext/standard/tests/streams/opendir-003.php on line 10
003+ 
005+ error:0A000415:SSL routines::sslv3 alert certificate expired in /usr/local/src/php/ext/ftp/tests/server.inc on line 115
006+ SSLv23 handshake failed.
007+ 
002-  in %s on line %d
     bool(false)

Not introduced in this PR.

❄️ Known flaky: ext/standard/tests/streams/opendir-004.phpt (opendir() with 'ftps://' stream.) from PHP.ext.standard.tests.streams  

002+ error:0A000415:SSL routines::sslv3 alert certificate expired in /usr/local/src/php/ext/ftp/tests/server.inc on line 115
003+ 
005+ error:0A000086:SSL routines::certificate verify failed in /usr/local/src/php/ext/standard/tests/streams/opendir-004.php on line 10
001- resource(%d) of type (stream)
002- string(5) "file1"
003- string(5) "file1"
004- string(3) "fil"
005- string(4) "b0rk"
006+ SSLv23 handshake failed.
007+ 
...

Not introduced in this PR.

View all 35 failed jobs.

ℹ️ Info

No other issues found (see more)

❄️ No new flaky tests detected

🔄 Datadog auto-retried 1 job - 1 passed on retry

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 60.65% (+0.00%)

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[bwoebi]

Looks right!

[pr-commenter]

Benchmarks [ tracer ]

Benchmark execution time: 2026-07-24 19:07:21

Comparing candidate commit c18198c in PR branch glopes/fix-leak-user-req-tel with baseline commit f068c9e in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 194 metrics, 0 unstable metrics.

Explanation

This is an A/B test comparing a candidate commit's performance against that of a baseline commit. Performance changes are noted in the tables below as:

• 🟩 = significantly better candidate vs. baseline
• 🟥 = significantly worse candidate vs. baseline

We compute a confidence interval (CI) over the relative difference of means between metrics from the candidate and baseline commits, considering the baseline as the reference.

If the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD), the change is considered significant.

Feel free to reach out to #apm-benchmarking-platform on Slack if you have any questions.

More details about the CI and significant changes

You can imagine this CI as a range of values that is likely to contain the true difference of means between the candidate and baseline commits.

CIs of the difference of means are often centered around 0%, because often changes are not that big:

---------------------------------(------|---^--------)-------------------------------->
                              -0.6%    0%  0.3%     +1.2%
                                 |          |        |
         lower bound of the CI --'          |        |
sample mean (center of the CI) -------------'        |
         upper bound of the CI ----------------------'

As described above, a change is considered significant if the CI is entirely outside the configured SIGNIFICANT_IMPACT_THRESHOLD (or the deprecated UNCONFIDENCE_THRESHOLD).

For instance, for an execution time metric, this confidence interval indicates a significantly worse performance:

----------------------------------------|---------|---(---------^---------)---------->
                                       0%        1%  1.3%      2.2%      3.1%
                                                  |   |         |         |
       significant impact threshold --------------'   |         |         |
                      lower bound of CI --------------'         |         |
       sample mean (center of the CI) --------------------------'         |
                      upper bound of CI ----------------------------------'