[duplicate-code] strings.Index/Count Comparison Analyzers Share Duplicated Match+Report Logic #65438

🔍 Duplicate Code Detected: strings.Index/Count Comparison Analyzers

Analysis of commit 31e5fda

Assignee: @copilot

Summary

The analyzers stringsindexcontains, stringscountcontains, and stringsindexhasprefix in pkg/linters/ share a near-identical structure: a BinaryExpr preorder walk, the same skip/nolint guards, a match*Comparison function that normalizes operands and matches a comparison operator against a sentinel literal (-1/0/1), and the same diagnostic-building/BuildContainsFix tail. Only the operator/literal table and the replacement function name differ.

expr, ok := n.(*ast.BinaryExpr)
if !ok { return }
pos := pass.Fset.PositionFor(expr.Pos(), false)
if filecheck.ShouldSkipFilename(pos.Filename, generatedFiles) { return }
if nolint.HasDirectiveForLinter(pos, noLintIndex, "<name>") { return }
call, negated, matched := match<X>Comparison(pass, expr)
if !matched { return }
// ... extract sText/subText/pkgText via astutil.NodeText/CallQualifierText ...
// build "use [!]strings.Contains(...)" message
fix := astutil.BuildContainsFix(pass.Files, expr, pkgText, sText, subText, negated, "...")
pass.Report(analysis.Diagnostic{Pos: expr.Pos(), End: expr.End(), Message: msg, SuggestedFixes: fix})

Impact Analysis

• Maintainability: Changes to operand normalization, yoda-order handling, or diagnostic wording must be repeated in three analyzers.
• Bug Risk: Subtle inconsistencies in supported operator/literal combinations are easy to introduce when copy-editing one file.
• Code Bloat: ~100 lines of duplicated analyze/report scaffolding.

Refactoring Recommendations

1. Introduce a table-driven comparison analyzer helper

   • Add astutil support for "comparison of strings.(Method)(...) against sentinel literals → suggested replacement", parameterized by method name, an operator/literal → negated table, and the replacement builder.
   • Estimated effort: 4-5 hours
   • Benefits: the three analyzers become small declarations of their operator tables and messages.

2. Extract the shared report tail

   • Factor the sText/subText/pkgText extraction + message/fix/Report block into one helper taking negated and a label.

Implementation Checklist

• Review duplication findings
• Prioritize refactoring tasks
• Create refactoring plan
• Implement table-driven helper in astutil
• Migrate the three analyzers
• Update tests
• Verify no functionality broken

Generated by 🔍 Duplicate Code Detector · pi · opus48 · 361.7 AIC · ⌖ 46.9 AIC · ⊞ 4.4K · ◷

• expires on Oct 5, 2026, 2:50 PM UTC-08:00