perf: return ImmutableContext.EMPTY from NoOpTransactionContextPropag…

[tobias-ibounig-dt]

This PR

NoOpTransactionContextPropagator.getTransactionContext() is called on every flag evaluation to retrieve the transaction context. The default implementation returned new ImmutableContext() on every call, allocating a new ImmutableContext, ImmutableStructure, and a HashMap each time — even though the result is always semantically identical.

Fix

Return the existing ImmutableContext.EMPTY singleton instead of allocating a new instance. Since ImmutableContext is immutable and NoOpTransactionContextPropagator always returns an empty context, the singleton is a correct and safe substitute.

Benchmark

Metric	Before	After	Delta
run:+totalAllocatedInstances	2,252,509	2,013,891	−238,618 (−10.6%)
run:+totalAllocatedBytes	107,492,056	103,293,456	−4,198,600 (−3.9%)

Follow-up Tasks

• Update benchmark.txt after all PRs are applied

[coderabbitai]

📝 Walkthrough

Walkthrough

NoOpTransactionContextPropagator.getTransactionContext() is changed to return the shared ImmutableContext.EMPTY singleton instead of constructing a new ImmutableContext on each call. A new unit test verifies the returned instance is the same singleton via identity equality.

Changes

NoOpTransactionContextPropagator singleton return

Layer / File(s)	Summary
Return ImmutableContext.EMPTY singleton and verify identity src/main/java/dev/openfeature/sdk/NoOpTransactionContextPropagator.java, src/test/java/dev/openfeature/sdk/NoOpTransactionContextPropagatorTest.java	getTransactionContext() returns ImmutableContext.EMPTY instead of new ImmutableContext(); new test getTransactionContextReturnsEmptySingleton asserts the result is the same singleton instance using assertThat(...).isSameInstanceAs(ImmutableContext.EMPTY).

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main optimization: returning ImmutableContext.EMPTY singleton from NoOpTransactionContextPropagator instead of allocating new instances.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.10%. Comparing base (cc837b1) to head (ee09adf).

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1975      +/-   ##
============================================
+ Coverage     92.11%   93.10%   +0.98%     
- Complexity      660      663       +3     
============================================
  Files            59       59              
  Lines          1624     1624              
  Branches        182      182              
============================================
+ Hits           1496     1512      +16     
+ Misses           80       66      -14     
+ Partials         48       46       -2     

Flag	Coverage Δ
unittests	93.10% <100.00%> (+0.98%)	⬆️

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud