#150: Implement class inheritance pattern

[marinka-aa]

Summary by CodeRabbit

• New Features
  • Added a new rule to detect when classes use implementation inheritance (extends) and report the affected lines.
• Documentation
  • Expanded the pattern guide with additional documented patterns and examples, including class inheritance.
• Tests
  • Added Java fixtures and unit tests covering simple inheritance, nested classes, and non-matching cases (implements-only and extends via type bounds).

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 40623217-e3b9-48a7-bacc-f7c2f55f5622

📥 Commits

Reviewing files that changed from the base of the PR and between 4014272 and 8e96527.

📒 Files selected for processing (5)

• test/patterns/class_inheritance/NestedInheritance.java
• test/patterns/class_inheritance/OnlyImplements.java
• test/patterns/class_inheritance/SimpleInheritance.java
• test/patterns/class_inheritance/TypeParameterExtends.java
• test/patterns/class_inheritance/test_class_inheritance.py

✅ Files skipped from review due to trivial changes (1)

• test/patterns/class_inheritance/NestedInheritance.java

🚧 Files skipped from review as they are similar to previous changes (4)

• test/patterns/class_inheritance/SimpleInheritance.java
• test/patterns/class_inheritance/TypeParameterExtends.java
• test/patterns/class_inheritance/test_class_inheritance.py
• test/patterns/class_inheritance/OnlyImplements.java

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📝 Walkthrough

Walkthrough

Adds a new ClassInheritance pattern, registers it as P34, updates pattern documentation, and adds Java fixtures plus Python tests for inheritance, implements-only, generic bounds, and nested classes.

Changes

Class inheritance pattern and docs

Layer / File(s)	Summary
Pattern catalog updates PATTERNS.md	Adds documented pattern entries P12-P27 and the new P34 class inheritance entry with descriptions and examples.
Pattern implementation and registration aibolit/patterns/class_inheritance/*, aibolit/config.py	Implements ClassInheritance for classes with extends, and registers P34 in the pattern configuration.
Fixtures and tests test/patterns/class_inheritance/*.java, test/patterns/class_inheritance/test_class_inheritance.py	Adds inheritance-related Java fixtures and unit tests that verify detected line numbers and non-matches.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Suggested reviewers

• ivanovmg

Poem

I hopped through patterns, P34 in sight,
With ears in the config, all snug and tight.
The tests went thump on extends and Base,
And bunny-checks lit up the AST race.
Hooray for code hops! 🐇

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 16.67% 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
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and accurately summarizes the main change: adding the class inheritance pattern.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 PMD (7.25.0)

test/patterns/class_inheritance/TypeParameterExtends.java

[ERROR] Error at scripts/ruleset.xml:23:36
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^^^^^ Value should be 'countImports'

24|
25| : '|' should be 'countImports'
[ERROR] Error at scripts/ruleset.xml:19:3
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^^^^^ Error while parsing rule reference

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21| : Error at scripts/ruleset.xml:23:36
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^^^^^ Value should be 'countImports'

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[ERROR] Cannot load ruleset scripts/ruleset.xml: 2 XML validation errors occurred
[WARN] Progressbar rendering conflicts with reporting to STDOUT. No progressbar will be shown. Try running with argument -r to output the report to a file instead.

test/patterns/class_inheritance/SimpleInheritance.java

[ERROR] Error at scripts/ruleset.xml:23:36
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^^^^^ Value should be 'countImports'

24|
25| : '|' should be 'countImports'
[ERROR] Error at scripts/ruleset.xml:19:3
17|
18|
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^^^^^ Error while parsing rule reference

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21| : Error at scripts/ruleset.xml:23:36
21|
22|
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^^^^^ Value should be 'countImports'

24|
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[ERROR] Cannot load ruleset scripts/ruleset.xml: 2 XML validation errors occurred
[WARN] Progressbar rendering conflicts with reporting to STDOUT. No progressbar will be shown. Try running with argument -r to output the report to a file instead.

test/patterns/class_inheritance/NestedInheritance.java

[ERROR] Error at scripts/ruleset.xml:23:36
21|
22|
23|
^^^^^ Value should be 'countImports'

24|
25| : '|' should be 'countImports'
[ERROR] Error at scripts/ruleset.xml:19:3
17|
18|
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^^^^^ Error while parsing rule reference

20|
21| : Error at scripts/ruleset.xml:23:36
21|
22|
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^^^^^ Value should be 'countImports'

24|
25|
[ERROR] Cannot load ruleset scripts/ruleset.xml: 2 XML validation errors occurred
[WARN] Progressbar rendering conflicts with reporting to STDOUT. No progressbar will be shown. Try running with argument -r to output the report to a file instead.

• 1 others

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[coderabbitai]

Actionable comments posted: 4

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@test/patterns/class_inheritance/NestedInheritance.java`:
- Around line 1-9: The fixture in NestedInheritance.java is missing the standard
SPDX license header, which is causing the copyrights check to fail in CI. Add
the repository’s usual SPDX header at the very top of the file before the
package declaration, keeping the existing Outer and Inner class definitions
unchanged.

In `@test/patterns/class_inheritance/OnlyImplements.java`:
- Around line 1-5: The fixture in OnlyImplements is missing the required SPDX
copyright header, which is causing the copyrights check to fail. Add the
standard SPDX license header at the top of the file before the package
declaration, keeping the existing Base and MyList definitions unchanged.

In `@test/patterns/class_inheritance/SimpleInheritance.java`:
- Around line 1-5: The fixture is missing the required SPDX license header,
causing the copyrights check to fail. Add the standard SPDX header at the top of
this Java file before the package declaration, keeping the existing Base and
MyList class definitions unchanged.

In `@test/patterns/class_inheritance/TypeParameterExtends.java`:
- Around line 1-4: Add the standard SPDX copyright header at the top of the
fixture before the package declaration in GenericBox so the copyrights check
passes. Keep the class definition unchanged and insert the repo’s standard
header in this file, ensuring it appears before patterns.class_inheritance and
matches the existing SPDX format used in other fixtures.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 6e467bf0-b11e-4907-b532-35ce5640aa44

📥 Commits

Reviewing files that changed from the base of the PR and between a3ace02 and 4014272.

📒 Files selected for processing (9)

• PATTERNS.md
• aibolit/config.py
• aibolit/patterns/class_inheritance/__init__.py
• aibolit/patterns/class_inheritance/class_inheritance.py
• test/patterns/class_inheritance/NestedInheritance.java
• test/patterns/class_inheritance/OnlyImplements.java
• test/patterns/class_inheritance/SimpleInheritance.java
• test/patterns/class_inheritance/TypeParameterExtends.java
• test/patterns/class_inheritance/test_class_inheritance.py