feat(interop): add Result.fromOptional and Try.fromOptional (#45)

[domix]

Bridge java.util.Optional to both Result and Try:

• Result.fromOptional(Optional<V>) → Result<V, NoSuchElementException>
• Try.fromOptional(Optional<V>, Supplier<Throwable>) → Try<V>

Includes null-guard validation and 7 new tests in InteropTest.

Pull Request

📌 Summary

Briefly describe the purpose of this pull request and what problem it solves.

Example: This PR adds a functional implementation of a lazy list, demonstrating deferred computation using Java 17 features.

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✅ Checklist

Please check all that apply:

• I have tested my changes locally
• I have added unit tests where applicable
• I have updated documentation where necessary
• My code follows the project's coding conventions
• I have linked any related issue(s) below

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🔗 Related Issues

Closes #45
Fixes #[issue-number]
(Related but not closing: #[issue-number])

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💬 Additional Notes

Any other context, screenshots, design decisions, or points to be reviewed carefully.

Summary by CodeRabbit

Release Notes

• New Features

  • Added conversion utilities to transform Java Optional instances into Result and Try types, enabling seamless interoperability with automatic error handling for empty Optionals.

• Tests

  • Added comprehensive test coverage for Optional interoperability with Result and Try, including edge cases such as null handling and lazy evaluation behavior.

[coderabbitai]

📝 Walkthrough

Walkthrough

Added factory methods to Result and Try classes for converting Java's Optional type. Result.fromOptional converts present/empty Optionals to Ok/Err variants with NoSuchElementException for empty cases. Try.fromOptional accepts a supplier for custom error handling. Comprehensive tests validate both conversions and edge cases.

Changes

Cohort / File(s)	Summary
Optional Interop Methods lib/src/main/java/codes/domix/fun/Result.java, lib/src/main/java/codes/domix/fun/Try.java	Added static factory methods to convert Optional to Result and Try. Result variant maps present→Ok, empty→Err(NoSuchElementException). Try variant maps present→Success, empty→Failure(supplier.get()). Both include null validation.
Optional Interop Tests lib/src/test/java/codes/domix/fun/InteropTest.java	Added comprehensive test suite covering Result.fromOptional and Try.fromOptional with present/empty states, error type validation, null input handling, lazy evaluation of supplier, and null supplier rejection.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• PR #36: Both PRs add Java Optional interop and modify Result/Try conversion utilities with similar factory method patterns.
• PR #16: Both PRs introduce Optional/Option interop methods and expand the same core Result.java and Try.java files with conversion utilities.

Poem

🐰 Optional came hopping by,
Said "Convert me, give it a try!"
Result and Try both lent a hand,
Now Optional works across the land! 🎉
From empty to error, present to success,
No more manual wrapping mess!

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 38.46% 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
Title check	✅ Passed	The title clearly and specifically describes the main change: adding Result.fromOptional and Try.fromOptional methods for Optional interop.
Description check	✅ Passed	The description partially follows the template with a summary of changes and linked issue reference, but multiple checklist items are not completed.
Linked Issues check	✅ Passed	The PR implements Result.fromOptional and Try.fromOptional as specified in issue #45, with null-guard validation and comprehensive tests. Option interop methods were not included but were noted as proposed in the issue.
Out of Scope Changes check	✅ Passed	All changes are in-scope: two new conversion methods in Result and Try classes, supporting imports, and comprehensive test coverage in InteropTest.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feature/optional_interop

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[github-actions]

Overall Project	99.15%	🍏
Files changed	100%	🍏

File	Coverage
Try.java	99.32%	🍏
Result.java	98.31%	🍏

[domix]

@coderabbitai review

[coderabbitai]

✅ Actions performed

Review triggered.

Note: CodeRabbit is an incremental review system and does not re-review already reviewed commits. This command is applicable only when automatic reviews are paused.

[coderabbitai]

🧹 Nitpick comments (1)

lib/src/test/java/codes/domix/fun/InteropTest.java (1)

168-178: Add one test for exceptionSupplier returning null.

This is a useful edge case to pin the Line 697 contract in Try.fromOptional.

Proposed test addition

 `@Test`
 void try_fromOptional_nullSupplier_throwsNPE() {
     assertThrows(NullPointerException.class,
         () -> Try.fromOptional(Optional.empty(), null));
 }
+
+@Test
+void try_fromOptional_supplierReturningNull_throwsNPE() {
+    assertThrows(NullPointerException.class,
+        () -> Try.fromOptional(Optional.empty(), () -> null));
+}

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@lib/src/test/java/codes/domix/fun/InteropTest.java` around lines 168 - 178,
Add a test that verifies Try.fromOptional throws a NullPointerException when the
provided exceptionSupplier returns null: create a new test method (e.g.,
try_fromOptional_exceptionSupplierReturningNull_throwsNPE) that calls
Try.fromOptional(Optional.empty(), () -> null) and uses
assertThrows(NullPointerException.class, ...) to assert the behavior; reference
the Try.fromOptional method and the exceptionSupplier lambda in the test so the
edge case at the method's contract is covered.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@lib/src/test/java/codes/domix/fun/InteropTest.java`:
- Around line 168-178: Add a test that verifies Try.fromOptional throws a
NullPointerException when the provided exceptionSupplier returns null: create a
new test method (e.g.,
try_fromOptional_exceptionSupplierReturningNull_throwsNPE) that calls
Try.fromOptional(Optional.empty(), () -> null) and uses
assertThrows(NullPointerException.class, ...) to assert the behavior; reference
the Try.fromOptional method and the exceptionSupplier lambda in the test so the
edge case at the method's contract is covered.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 6a168317-6fab-4535-90a1-822f69c20059

📥 Commits

Reviewing files that changed from the base of the PR and between b5a3cf4 and e70653e.

📒 Files selected for processing (3)

• lib/src/main/java/codes/domix/fun/Result.java
• lib/src/main/java/codes/domix/fun/Try.java
• lib/src/test/java/codes/domix/fun/InteropTest.java

[github-actions]

Overall Project	99.15%	🍏
Files changed	100%	🍏

File	Coverage
Try.java	99.32%	🍏
Result.java	98.31%	🍏