Ensure default module is always documented

[amika-d]

Purpose

Currently, bal doc generates a blank screen for the default module of certain libraries (like ballerinax/mysql) because the docerina generator skips modules that are not explicitly listed in the exportedModules list.

This PR fixes the issue by ensuring that Default Modules are always processed, regardless of the export list configuration.

Approach

Updated BallerinaDocGenerator.java to bypass the exportedModules check if module.isDefaultModule() is true. This ensures the main module of a package is never hidden by the documentation tool.

Automation Tests

• Unit tests added
• Manual verification

Verification Details:
Verified locally by running the patched tool against a reproduction of the ballerinax/mysql project. The API documentation for the default module, which previously resulted in a blank screen, now generates correctly.

Fixes #44476

ballerina-fix.mp4

[CLAassistant]

All committers have signed the CLA.

[coderabbitai]

📝 Walkthrough

Walkthrough

The change modifies the module documentation generation logic to allow the default module to bypass export filtering, while maintaining restrictions on non-default modules. This targets a specific behavioral exception during module documentation map generation.

Changes

Cohort / File(s)	Summary
Module Documentation Generation misc/docerina/src/main/java/org/ballerinalang/docgen/docs/BallerinaDocGenerator.java	Modified skip condition in generateModuleDocMap to treat default module specially, allowing it inclusion regardless of exportedModules membership while preserving filtering for non-default modules.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 Hop, hop—the docs now dance with glee,
Default modules finally free!
No more blank pages, just API delight,
The rabbit's fix made the packages bright! 🎉

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: ensuring default modules are always documented, which directly addresses the core issue.
Linked Issues check	✅ Passed	The code changes directly address the linked issue #44476 by modifying the module skip logic to always include default modules, fixing the blank documentation view for default packages.
Out of Scope Changes check	✅ Passed	The changes are tightly focused on the documented objective: modifying the skip condition for modules in BallerinaDocGenerator.java to ensure default modules are processed.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Description check	✅ Passed	The PR description covers Purpose, Approach, and verification details, aligning well with the template structure, though some optional sections differ slightly from the template format.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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