perf: return Collections.emptyMap() from asUnmodifiableMap() when attributes is empty

[tobias-ibounig-dt]

This PR

• AbstractStructure.asUnmodifiableMap() returns a shared static EMPTY_UNMODIFIABLE_MAP constant when attributes is empty, instead of allocating a new UnmodifiableMap wrapper on every call

Related Issues

None

Notes

Collections.unmodifiableMap(m) always allocates a new wrapper object, even when m is empty. For empty structures the result is always semantically identical, so the wrapper can be replaced with a single static instance. The constant is typed as Map<String, Value> and backed by Collections.unmodifiableMap(Collections.emptyMap()), so callers see no behavioral difference.

This path is not exercised by the current benchmark workload.

Follow-up Tasks

• Update benchmark.txt after all PRs are applied

Summary by CodeRabbit

Release Notes

• Bug Fixes

  • Improved unmodifiable map handling in structures so empty or null-initialized attributes now reliably return an empty map.

• Tests

  • Added coverage for unmodifiable map behavior on empty and null-backed structures, including verification that returned maps cannot be modified.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 728807a8-d62e-4272-87af-4eee7b88920d

📥 Commits

Reviewing files that changed from the base of the PR and between c812b44 and 9202413.

📒 Files selected for processing (2)

• src/main/java/dev/openfeature/sdk/AbstractStructure.java
• src/test/java/dev/openfeature/sdk/MutableStructureTest.java

🚧 Files skipped from review as they are similar to previous changes (2)

• src/main/java/dev/openfeature/sdk/AbstractStructure.java
• src/test/java/dev/openfeature/sdk/MutableStructureTest.java

---

📝 Walkthrough

Walkthrough

AbstractStructure.asUnmodifiableMap() gains a null/empty guard that returns Collections.emptyMap() when attributes is null or empty. Two new tests in MutableStructureTest verify that both an empty structure and a null-backed structure return an empty, unmodifiable map.

Changes

Null/empty guard in asUnmodifiableMap

Layer / File(s)

Summary

asUnmodifiableMap guard + tests src/main/java/dev/openfeature/sdk/AbstractStructure.java, src/test/java/dev/openfeature/sdk/MutableStructureTest.java

asUnmodifiableMap() now returns Collections.emptyMap() when attributes is null or empty. Two new test methods assert the returned map is empty and throws UnsupportedOperationException on mutation, covering both the empty-structure and null-backed-structure scenarios. Import statements in the test class are updated to add AssertJ's assertThat and switch from a wildcard JUnit import to a named import.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 20.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly and accurately describes the main change: optimizing asUnmodifiableMap() to return Collections.emptyMap() when attributes are empty, which is the core improvement in this performance-focused pull request.
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.

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/main/java/dev/openfeature/sdk/AbstractStructure.java`:
- Around line 32-34: The early return of Collections.emptyMap() when attributes
is empty but non-null breaks consistency with the live-view semantics of
asUnmodifiableMap() that is applied in the non-empty branch. Instead of
returning Collections.emptyMap() in the condition checking if attributes is null
or empty, remove the isEmpty() check from the conditional at line 32 so that
both empty and non-empty attributes maps are processed through the same
asUnmodifiableMap() logic used at line 35, ensuring consistent behavior
regardless of map size.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 4cfc6f27-ef9b-48e4-a981-9a7b8dda9b5c

📥 Commits

Reviewing files that changed from the base of the PR and between cc837b1 and c812b44.

📒 Files selected for processing (2)

• src/main/java/dev/openfeature/sdk/AbstractStructure.java
• src/test/java/dev/openfeature/sdk/MutableStructureTest.java

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.11%. Comparing base (cc837b1) to head (9202413).

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1974      +/-   ##
============================================
+ Coverage     92.11%   93.11%   +0.99%     
- Complexity      660      665       +5     
============================================
  Files            59       59              
  Lines          1624     1626       +2     
  Branches        182      182              
============================================
+ Hits           1496     1514      +18     
+ Misses           80       66      -14     
+ Partials         48       46       -2     

Flag	Coverage Δ
unittests	93.11% <100.00%> (+0.99%)	⬆️

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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