feat: add flag metadata

[Kavindu-Dodan]

This PR

Is connected to #437 & completes the implementation of flag metadata spec implementation [1]

The implementation is backed by immutable FlagMetadata. If present, metadata gets propagated from ProviderEvaluation to FlagEvaluationDetails

Tests were added to validate the construction as well as the propagation

[1] - open-feature/spec@74c373e

[codecov]

Codecov Report

Merging #459 (207545b) into main (5f173ff) will decrease coverage by 0.45%.
The diff coverage is 100.00%.

❗ Current head 207545b differs from pull request most recent head e78fed7. Consider uploading reports for the commit e78fed7 to get more accurate results

@@             Coverage Diff              @@
##               main     #459      +/-   ##
============================================
- Coverage     94.09%   93.65%   -0.45%     
+ Complexity      257      231      -26     
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  Files            24       24              
  Lines           576      536      -40     
  Branches         35       33       -2     
============================================
- Hits            542      502      -40     
  Misses           17       17              
  Partials         17       17              

Flag	Coverage Δ
unittests	93.65% <100.00%> (-0.45%)	⬇️

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Impacted Files	Coverage Δ
...ava/dev/openfeature/sdk/FlagEvaluationDetails.java	100.00% <100.00%> (ø)
...rc/main/java/dev/openfeature/sdk/FlagMetadata.java	100.00% <100.00%> (ø)

... and 3 files with indirect coverage changes

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[toddbaert]

@Kavindu-Dodan this all looks good to me, except that I'm not sure about throwing on failed retrieval.

This seems like a typical eventuality, not an exceptional one.

[Kavindu-Dodan]

@Kavindu-Dodan this all looks good to me, except that I'm not sure about throwing on failed retrieval.

This seems like a typical eventuality, not an exceptional one.

Updated the implementation to avoid exceptions. Instead now we return null for missing key & value type differences , along with debug level log entry

cc - @thisthat

[thiyagu06]

LGTM 👍

[toddbaert]

@Kavindu-Dodan I rebased on main and resolved conflicts with @lopitz 's recent PR. I hope you don't mind. This looks good to me, and we have lots of approvals so I'm merging.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
3 Code Smells

No Coverage information
0.0% Duplication