[dmytrodanilenkov]

Fixes #32

DataModel.Data.toStorageType() built an ImmutableMap keyed by flag key, so a payload with the same key twice (e.g. featbit-agent still holding an archived copy of a flag that was deleted and re-created) threw "Multiple entries with same key" and failed the whole sync, leaving new clients in a reconnect loop.

Collect items into a LinkedHashMap so the last entry wins, as the Go, Python, Rust, Ruby and Node SDKs already do.

Confidence Score: 5/5

This PR appears safe to merge.

Summary

The PR lets data sync accept repeated flag keys and segment IDs instead of throwing an exception.

• Data sync keeps the last item when a payload repeats a key.

_{Reviews (1) · Last reviewed commit: "fix: tolerate duplicate flag keys in dat..." · Reviewed by Greptile}

Summary by CodeRabbit

• Bug Fixes
  • Feature flags and segments with duplicate identifiers now consistently retain the last entry provided. Active entries are preserved when they follow archived copies, and stored configuration no longer reflects an earlier duplicate.

[coderabbitai]

No actionable comments were generated in the recent review.

Walkthrough

Data.toStorageType() now uses insertion-ordered maps keyed by item ID. When IDs repeat, the last feature flag or segment entry is retained. Tests cover duplicate and distinct feature flag IDs.

Changes: Storage conversion

Layer / File(s)	Summary
Duplicate-ID handling src/main/java/co/featbit/server/DataModel.java, src/test/java/co/featbit/server/DataModelTest.java	Data.toStorageType() uses last-entry-wins maps for feature flags and segments, then copies the maps to immutable maps. Tests cover archived and live flags with the same ID, duplicate archived flags, and distinct IDs.

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix · Severity of issue fixed: Medium

Possibly related issues

• featbit/featbit-java-sdk#32: The change addresses the reported full-sync failure caused by an archived and live flag with the same key.

Suggested reviewers: dsun0720

Merge Risk: Minimal · up to 1f20a

Data sync payloads with duplicate flag keys no longer fail the whole sync. The last entry for each key is kept, consistent with other FeatBit SDKs. No concrete merge-blocking risk was found.

Pre-merge checks: 5

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly summarizes the main change: handling duplicate flag keys in data sync payloads.
Docstring Coverage		Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentat…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 1 functions across 2 files.

Finishing Touches

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Commits

Reviewing files that changed from the base of the PR and between 4741389 and 1f20ae8.

Files selected for processing: 2

• src/main/java/co/featbit/server/DataModel.java
• src/test/java/co/featbit/server/DataModelTest.java

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