Add support for Gradle version catalog dependencies

[Kaushik-Kumar-CEG]

Fixes #4521

Issue

Gradle parser reports incomplete Maven PURLs (e.g., pkg:maven/androidx) when scanning build.gradle files that use version catalog references like libs.androidx.appcompat.

Approach

• Parse gradle/libs.versions.toml to resolve version catalog aliases to full Maven coordinates
• Add DEPENDENCY-VERSION-CATALOG grammar rule to match libs.x.y.z patterns in the existing pygmars parser
• Resolve catalog references during dependency extraction to generate complete PURLs

Before Fix:

• Input: implementation libs.androidx.appcompat
• Output: pkg:maven/androidx ❌ (incomplete)

After Fix:

• Input: implementation libs.androidx.appcompat
• Output: pkg:maven/androidx.appcompat/appcompat@1.6.1 ✅ (complete)

Summary of Changes

Modified:

• src/packagedcode/build_gradle.py

  • Added TOML import for parsing version catalogs
  • Added grammar rule for version catalog syntax
  • Added parse_version_catalog() function to read and parse libs.versions.toml
  • Updated get_dependencies() to resolve catalog references

• tests/packagedcode/test_build_gradle.py

  • Added test case for version catalog resolution

Added:

• tests/packagedcode/data/build_gradle/groovy/fdroid-version-catalog/
  • Test build.gradle with catalog references
  • Sample libs.versions.toml file
  • Expected output with resolved PURLs

Implementation Details

Studied existing gradle parser patterns and followed the codebase conventions:

• Used existing grammar-based parsing approach (consistent with DEPENDENCY-1 through DEPENDENCY-4 patterns)
• Matched code style, naming conventions, and error handling patterns from similar functions
• Minimal comments following repo standards

Verification

All tests pass

• Ran full test suite for gradle parser (22 tests)
• Verified existing groovy and kotlin tests still work
• Tested edge cases: missing catalog, unresolved references, mixed dependencies
• Confirmed no syntax errors and code compiles cleanly

BEFORE FIX

AFTER FIX

Ready for review. Happy to address any feedback or make adjustments as needed

---

Tasks

• Reviewed contribution guidelines
• PR is descriptively titled 📑 and links the original issue above 🔗
• Tests pass -- look for a green checkbox ✔️ a few minutes after opening your PR
• Commits are in uniquely-named feature branch and has no merge conflicts 📁
• Updated documentation pages (if applicable)
• Updated CHANGELOG.rst (if applicable)

---