find-dead-code

# Find Dead Code Detect unused Go code that can be safely removed. ## Rules - Report findings, do not delete. Removal is a separate task. - Focus on production code (`internal/`, `api/`, `cmd/`). Skip tests unless explicitly asked. - Tools have false positives — classify each finding before recommending removal. - Code used via reflection or dynamic dispatch (e.g. Kubernetes controller-runtime, interface implementations) is not dead. ## Step 1: Determine Scope Ask the user: - **Branch mode**: only files changed in the current branch vs main. - **Full mode**: scan the entire codebase. For branch mode: ```bash git diff --name-only upstream/main -- 'internal/' 'api/' 'cmd/' | grep '\.go$' | grep -v '_test\.go$' ``` ## Step 2: Run Go Standard Tooling Check for unused code with the compiler: ```bash go build ./... 2>&1 | grep "declared and not used" go vet ./... 2>&1 | grep -E "(not used|never used)" ``` ## Step 3: Run staticcheck staticcheck detects unused code, including unexported functions, constants, and variables: ```bash staticcheck -checks=U1000 ./... ``` U1000 reports unused code that is not exported and not referenced. ## Step 4: Run deadcode (Go 1.23+) If Go 1.23+ is available: ```bash go run golang.org/x/tools/cmd/deadcode@latest -filter <package-pattern> ``` This finds functions, types, and variables that are never called or referenced. ## Step 5: Check Unused Imports ```bash goimports -l <target> ``` Any file listed has unused imports. Review with: ```bash goimports -d <file> ``` ## Step 6: Filter False Positives Common false positives in this codebase: | Pattern | Why it's not dead | |---------|-------------------| | `Reconcile(ctx, req)` implementations | Called by controller-runtime via interface | | `SetupWithManager()` functions | Called by manager setup code | | `init()` functions | Called automatically by Go runtime | | Interface method implementations | Called through interface, not directly | | `kubebuilder:` marker functions | Used by code generation | | Constants/vars in `constants.go` | May be used in tests or future code | | Error constants matching `Err*` pattern | May be used in error wrapping | ## Step 7: Classify Findings For each finding, classify: | Category | Criteria | Action | |----------|----------|--------| | **Remove** | Clearly unused, no interface/reflection use | Safe to delete | | **Verify** | Possibly used dynamically or via interface | Search for references before removing | | **False positive** | Interface impl, reflection, kubebuilder marker | Skip | For "Verify" findings, search for references: ```bash rg "<function_or_type_name>" internal/ api/ cmd/ test/ ``` ## Step 8: Report For each finding: 1. File and line number 2. What is unused (function, type, constant, variable, import) 3. Tool that detected it (staticcheck, deadcode, goimports) 4. Classification (remove / verify / false positive) 5. Estimated lines saved Summary: total findings, how many safe to remove, estimated cleanup size.