Fix SonarQube High severity issues for string duplication and cognitive complexity

[devin-ai-integration]

Summary

This PR addresses SonarQube High/Critical severity issues identified in the github-mcp-server repository by fixing code quality issues in two categories:

1. String literal duplication (rule go:S1192) in pkg/github/discussions.go
2. Cognitive complexity (rule go:S3776) in pkg/github/repositories.go

Changes

1. Fix String Literal Duplication in discussions.go

Added constants at the package level to eliminate repeated string literals:

• descRepositoryOwner = "Repository owner" (4 occurrences)
• descRepositoryName = "Repository name" (4 occurrences)
• errGitHubGQLClient = "failed to get GitHub GQL client: %v" (4 occurrences)
• discussionCategoryLabelFmt = "category:%s" (3 occurrences)

These constants are now used consistently across 4 functions: ListDiscussions, GetDiscussion, GetDiscussionComments, and ListDiscussionCategories.

2. Reduce Cognitive Complexity in repositories.go

Refactored the ListCommits function to reduce cognitive complexity from 23 to well below the threshold of 15:

• Created listCommitsParams struct to encapsulate function parameters
• Extracted parameter parsing logic into parseListCommitsParams helper function
• This separates validation concerns from business logic, making the code more maintainable

Review Checklist

Critical items to verify:

1. ✅ All string constant substitutions maintain identical behavior
2. ✅ Parameter parsing extraction preserves exact error handling paths
3. ✅ The PaginationParams type name is correctly capitalized (was initially lowercase, fixed during development)
4. ✅ All tests pass and lint is clean

What to look for:

• Confirm that error messages returned to users are unchanged
• Verify that the parameter parsing in parseListCommitsParams matches the original inline logic exactly
• Check that the struct field accesses (params.owner, params.repo, etc.) are correct

Testing

• ✅ ./script/lint passes with 0 issues
• ✅ ./script/test passes all test suites

Tradeoffs

• Constants scope: The new constants are package-private (lowercase names), which is appropriate for this use case. If similar patterns emerge in other packages, we may want to consider broader scoping.
• Extraction granularity: Only extracted parameter parsing, not the full function body, to keep changes minimal and focused on reducing complexity.

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Link to Devin run: https://app.devin.ai/sessions/20c43147c2b74e5f9a077535303e2d5b
Requested by: Shawn Azman (shawn@cognition.ai) (@ShawnAzman)

[devin-ai-integration]

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[sonarqubecloud]

Quality Gate failed

Failed conditions
5.8% Duplication on New Code (required ≤ 3%)

See analysis details on SonarQube Cloud