[linter-miner] linter: add sprintfbool — flag fmt.Sprintf("%t", b) → strconv.FormatBool(b)

cmd/linters/main.go

@@ -54,6 +54,7 @@ import (
 	"github.com/github/gh-aw/pkg/linters/regexpcompileinfunction"
 	"github.com/github/gh-aw/pkg/linters/seenmapbool"
 	"github.com/github/gh-aw/pkg/linters/sortslice"
+	"github.com/github/gh-aw/pkg/linters/sprintfbool"
 	"github.com/github/gh-aw/pkg/linters/sprintferrdot"
 	"github.com/github/gh-aw/pkg/linters/sprintferrorsnew"
 	"github.com/github/gh-aw/pkg/linters/sprintfint"
@@ -112,6 +113,7 @@ func main() {
 		sortslice.Analyzer,
 		sprintferrdot.Analyzer,
 		sprintferrorsnew.Analyzer,
+		sprintfbool.Analyzer,
 		sprintfint.Analyzer,
 		strconvparseignorederror.Analyzer,
 		stringreplaceminusone.Analyzer,

docs/adr/46898-add-sprintfbool-linter.md

@@ -0,0 +1,44 @@
+# ADR-46898: Add sprintfbool Linter to Flag fmt.Sprintf("%t", b) → strconv.FormatBool(b)
+
+**Date**: 2026-07-20
+**Status**: Draft
+**Deciders**: Unknown
+
+---
+
+### Context
+
+The repository maintains a suite of custom Go static analysis linters under `pkg/linters/`. A pre-existing `sprintfint` linter already flags `fmt.Sprintf("%d", n)` and recommends `strconv.Itoa(n)` for integer-to-string conversions, because `strconv` avoids the runtime reflection overhead of the `fmt` package. The same performance and clarity argument applies to boolean-to-string conversions: `fmt.Sprintf("%t", b)` uses reflection to format a `bool`, while `strconv.FormatBool(b)` is a direct, zero-allocation call. No existing linter in the suite catches this pattern, leaving a gap in consistency enforcement across the codebase.
+
+### Decision
+
+We will add a new `sprintfbool` analysis pass (`pkg/linters/sprintfbool/`) that reports `fmt.Sprintf("%t", b)` calls where `b` has the exact predeclared `bool` type, and provides a suggested fix that rewrites the call to `strconv.FormatBool(b)` while managing `fmt`/`strconv` import additions and removals automatically. The linter will be registered in `cmd/linters/main.go` alongside existing passes, will skip generated files, and will honour `//nolint:sprintfbool` suppression directives.
+
+### Alternatives Considered
+
+#### Alternative 1: Extend sprintfint to Cover Both Integer and Bool Patterns
+
+The `sprintfint` linter could be generalised into a broader "prefer strconv over fmt.Sprintf" pass covering both `%d`/int and `%t`/bool (and potentially other format verbs). This would reduce the number of top-level packages. It was not chosen because combining unrelated verb/type pairs in a single analyzer increases code complexity, makes the diagnostic messages harder to scope precisely, and conflicts with the single-responsibility design pattern already established by the existing linter suite (each linter addresses one specific pattern).
+
+#### Alternative 2: Rely on an External Linter (e.g., staticcheck S1039 or perfsprint)
+
+Third-party linters such as `staticcheck` or `perfsprint` can already flag some `fmt.Sprintf` patterns. Delegating to an external tool would avoid adding a new in-house package. This was not chosen because the repository uses an internal linter framework (`pkg/linters/internal/astutil`, `nolint`, `filecheck`) that provides repo-specific affordances (generated-file skipping, `//nolint` directive support, suggested-fix generation with import management). Adding an external tool dependency would require integrating and configuring a separate toolchain and would not benefit from those shared utilities.
+
+### Consequences
+
+#### Positive
+- Eliminates reflection overhead from `fmt.Sprintf("%t", b)` in flagged call sites, replacing it with the zero-allocation `strconv.FormatBool`.
+- Makes bool-to-string conversion intent explicit, consistent with the `sprintfint` rule and the broader repo style of preferring `strconv` for primitive conversions.
+- Suggested fixes automatically manage `fmt`/`strconv` imports, reducing friction when applying the rewrite.
+
+#### Negative
+- Adds a new custom package (`pkg/linters/sprintfbool/`) that must be maintained as the Go language, analysis framework, or internal utilities evolve.
+- Developers unfamiliar with the linter suite will encounter a new diagnostic category and must learn the `strconv.FormatBool` idiom; this is a minor onboarding cost.
+
+#### Neutral
+- The linter intentionally excludes named bool types (e.g., `type myBool bool`) to avoid false positives, since `strconv.FormatBool` requires the exact predeclared `bool` type. Callers using named bool types will not see diagnostics.
+- Calls using multiple arguments (e.g., `fmt.Sprintf("%t %t", a, b)`) or different format verbs (e.g., `%v`) are also excluded, preserving `fmt.Sprintf` where it provides genuine multi-arg formatting.
+
+---
+
+*ADR created by [adr-writer agent]. Review and finalize before changing status from Draft to Accepted.*