fix(ffe): isolate malformed flag configurations

[leoromanovsky]

Motivation

A malformed flag in a UFC payload must not prevent neighboring valid flags from being evaluated. Rejected flags must return the caller default with ERROR / PARSE_ERROR, while missing flags remain FLAG_NOT_FOUND.

Changes

• Pin ffe-system-test-data to the merged PR CircleCI integration doesn't work #26 corpus.
• Pin libdatadog to fix(ffe): report rejected flags as parse errors libdatadog#2339 (d20319f8a108b9ee738af41e7f49f1875ce3c245), which owns malformed-flag isolation and evaluation semantics.
• Adapt the PHP Rust workspace to libdatadog v40 API and crate naming changes without adding a PHP-side evaluator.
• Assert canonical fixture reason and error-code results.

Decisions

• Keep malformed flag parsing and SemVer behavior in libdatadog; PHP remains a narrow bridge.
• Treat rejected and absent flags as distinct contract states.
• Exercise the contract through the production PHP extension instead of duplicating fixture logic.

Validation

• cargo check -p datadog-php
• make test_c TESTS=tests/ext/ffe/system_test_data_evaluate.phpt MAX_TEST_PARALLELISM=1
• git diff --check

[datadog-prod-us1-6]

 

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⚠️ Warnings

🚦 78 Pipeline jobs failed

DataDog/apm-reliability/dd-trace-php | ASAN test_c: [8.0, arm64]     

🧪 6 Tests failed

All test failures are known flaky.

❄️ Known flaky: tmp/build_extension/tests/ext/telemetry/composer.phpt (Read telemetry via composer) from PHP.tmp.build_extension.tests.ext.telemetry  

--
                 [0] => Array
                     (
                         [name] => datadog/dd-trace
010+                     [hash] => 
011+                     [metadata] => 
                     )
     
                 [1] => Array
                     (
...

Not introduced in this PR.

❄️ Known flaky: tmp/build_extension/tests/ext/telemetry/integration.phpt (Signal integration telemetry) from PHP.tmp.build_extension.tests.ext.telemetry  

--
       ["integrations"]=>
       array(1) {
         [0]=>
007+     array(6) {
007-     array(5) {
           ["name"]=>
           string(37) "ddtrace\test\testsandboxedintegration"
           ["enabled"]=>
--
...

Not introduced in this PR.

View all failed tests

DataDog/apm-reliability/dd-trace-php | ASAN test_c: [8.5, arm64]     

🧪 6 Tests failed

All test failures are known flaky.

❄️ Known flaky: tmp/build_extension/tests/ext/telemetry/composer.phpt (Read telemetry via composer) from php.tmp.build_extension.tests.ext.telemetry  

--
                     (
                         [name] => datadog/dd-trace
                         [version] => dev-master
010+                     [hash] => 
011+                     [metadata] => 
                     )
     
                 [1] => Array
                     (
...

Not introduced in this PR.

❄️ Known flaky: tmp/build_extension/tests/ext/telemetry/integration.phpt (Signal integration telemetry) from php.tmp.build_extension.tests.ext.telemetry  

--
       ["integrations"]=>
       array(1) {
         [0]=>
007-     array(5) {
007+     array(6) {
           ["name"]=>
           string(37) "ddtrace\test\testsandboxedintegration"
           ["enabled"]=>
--
...

Not introduced in this PR.

View all failed tests

DataDog/apm-reliability/dd-trace-php | test_web_custom: [8.0, fpm-fcgi]     

🧪 1 Test failed

All test failures are known flaky.

❄️ Known flaky: testInstrumentation from custom-framework-autoloading-test.DDTrace\Tests\Integrations\Custom\Autoloaded\InstrumentationTest  

DDTrace\Tests\Integrations\Custom\Autoloaded\InstrumentationTest::testInstrumentation
Failed asserting that an array has the key 'logs_created'.

tests/Integrations/Custom/Autoloaded/InstrumentationTest.php:80
tests/Common/RetryTraitVersionGeneric.php:28

Not introduced in this PR.

View all 78 failed jobs.

ℹ️ Info

No other issues found (see more)

❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 100.00%
• Overall Coverage: 60.62% (-0.04%)

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