fix: fixing null pointer exception error

[Ayushman-Gaur]

fix: null pointer exceptionn error

• Adds null check for flag.getMetadata() in getFlagMetadata() to prevent
  NullPointerException when a flagd server doesn't support metadata.

Related Issues

Fixes #1708

Notes

currentFlagSetMetadata is always initialized as a new HashMap so it won't
be null, but flag.getMetadata() can return null on servers that don't support
metadata. Added a null guard before iterating over it.

How to test

A new test resolveBooleanValue_flagWithNullMetadata_doesNotThrowNPE has been
added to FlagdCoreTest that verifies no NPE is thrown when evaluating a flag
with no metadata defined.

[gemini-code-assist]

Summary of Changes

Hello, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a potential NullPointerException in the FlagdCore component by introducing a defensive null check when accessing flag metadata. It ensures the application remains robust even when flagd servers do not supply metadata, preventing crashes and improving stability. A new test case has been added to confirm the effectiveness of this fix.

Highlights

• Null Pointer Exception Fix: Implemented a null check for flag.getTargeting() within the getFlagMetadata() method to prevent NullPointerException when a flagd server does not provide metadata.
• New Test Case: Added resolveBooleanValue_flagWithNullMetadata_doesNotThrowNPE to FlagdCoreTest to validate that no NullPointerException is thrown when evaluating a flag with undefined metadata.

Changelog

• tools/flagd-core/src/main/java/dev/openfeature/contrib/tools/flagd/core/FlagdCore.java
  • Added a null check for flag.getTargeting() before iterating over flag metadata to prevent NullPointerException.
• tools/flagd-core/src/test/java/dev/openfeature/contrib/tools/flagd/core/FlagdCoreTest.java
  • Imported assertThatNoException from AssertJ.
  • Added a new test method resolveBooleanValue_flagWithNullMetadata_doesNotThrowNPE to verify that evaluating a flag with null metadata does not throw an exception.

Activity

• The author, Ayushman-Gaur, identified and fixed a NullPointerException related to flag.getMetadata() when flagd servers do not support metadata.
• A new test case, resolveBooleanValue_flagWithNullMetadata_doesNotThrowNPE, was added to FlagdCoreTest to demonstrate the fix and prevent regressions.
• The PR description provides detailed notes on the issue and instructions on how to test the changes.

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[gemini-code-assist]

Code Review

This pull request aims to fix a potential NullPointerException by adding a null check when accessing flag metadata, and includes a new test case to verify the fix. While the intention is good, the implementation of the fix in FlagdCore.java appears to be incorrect. The added condition flag.getTargeting() != null is effectively a no-op, as the getTargeting() method never returns null. I have provided a suggestion to correct the implementation to align with the stated goal of the pull request.

[Ayushman-Gaur]

The CI failure is in the go-feature-flag provider which is unrelated to my changes in flagd-core. This appears to be a pre-existing issue.

[cupofcat]

You should also guard the for loop against currentFlagSetMetadata being null.

[cupofcat]

Please solve the CI error with formatting too. Thanks for the contribution!