Add staticcheck tool

vendor/honnef.co/go/tools/simple/s1038/s1038.go

@@ -0,0 +1,190 @@
+package s1038
+
+import (
+	"fmt"
+	"go/ast"
+	"go/types"
+
+	"honnef.co/go/tools/analysis/code"
+	"honnef.co/go/tools/analysis/facts/generated"
+	"honnef.co/go/tools/analysis/lint"
+	"honnef.co/go/tools/analysis/report"
+	"honnef.co/go/tools/go/types/typeutil"
+	"honnef.co/go/tools/pattern"
+
+	"golang.org/x/tools/go/analysis"
+)
+
+var SCAnalyzer = lint.InitializeAnalyzer(&lint.Analyzer{
+	Analyzer: &analysis.Analyzer{
+		Name:     "S1038",
+		Run:      run,
+		Requires: append([]*analysis.Analyzer{generated.Analyzer}, code.RequiredAnalyzers...),
+	},
+	Doc: &lint.RawDocumentation{
+		Title:   "Unnecessarily complex way of printing formatted string",
+		Text:    `Instead of using \'fmt.Print(fmt.Sprintf(...))\', one can use \'fmt.Printf(...)\'.`,
+		Since:   "2020.1",
+		MergeIf: lint.MergeIfAny,
+	},
+})
+
+var Analyzer = SCAnalyzer.Analyzer
+
+var (
+	checkPrintSprintQ = pattern.MustParse(`
+		(Or
+			(CallExpr
+				fn@(Or
+					(Symbol "fmt.Print")
+					(Symbol "fmt.Sprint")
+					(Symbol "fmt.Println")
+					(Symbol "fmt.Sprintln"))
+				[(CallExpr (Symbol "fmt.Sprintf") f:_)])
+			(CallExpr
+				fn@(Or
+					(Symbol "fmt.Fprint")
+					(Symbol "fmt.Fprintln"))
+				[_ (CallExpr (Symbol "fmt.Sprintf") f:_)]))`)
+
+	checkTestingErrorSprintfQ = pattern.MustParse(`
+		(CallExpr
+			sel@(SelectorExpr
+				recv
+				(Ident
+					name@(Or
+						"Error"
+						"Fatal"
+						"Fatalln"
+						"Log"
+						"Panic"
+						"Panicln"
+						"Print"
+						"Println"
+						"Skip")))
+			[(CallExpr (Symbol "fmt.Sprintf") args)])`)
+
+	checkLogSprintfQ = pattern.MustParse(`
+		(CallExpr
+			(Symbol
+				(Or
+					"log.Fatal"
+					"log.Fatalln"
+					"log.Panic"
+					"log.Panicln"
+					"log.Print"
+					"log.Println"))
+			[(CallExpr (Symbol "fmt.Sprintf") args)])`)
+
+	checkSprintfMapping = map[string]struct {
+		recv        string
+		alternative string
+	}{
+		"(*testing.common).Error": {"(*testing.common)", "Errorf"},
+		"(testing.TB).Error":      {"(testing.TB)", "Errorf"},
+		"(*testing.common).Fatal": {"(*testing.common)", "Fatalf"},
+		"(testing.TB).Fatal":      {"(testing.TB)", "Fatalf"},
+		"(*testing.common).Log":   {"(*testing.common)", "Logf"},
+		"(testing.TB).Log":        {"(testing.TB)", "Logf"},
+		"(*testing.common).Skip":  {"(*testing.common)", "Skipf"},
+		"(testing.TB).Skip":       {"(testing.TB)", "Skipf"},
+		"(*log.Logger).Fatal":     {"(*log.Logger)", "Fatalf"},
+		"(*log.Logger).Fatalln":   {"(*log.Logger)", "Fatalf"},
+		"(*log.Logger).Panic":     {"(*log.Logger)", "Panicf"},
+		"(*log.Logger).Panicln":   {"(*log.Logger)", "Panicf"},
+		"(*log.Logger).Print":     {"(*log.Logger)", "Printf"},
+		"(*log.Logger).Println":   {"(*log.Logger)", "Printf"},
+		"log.Fatal":               {"", "log.Fatalf"},
+		"log.Fatalln":             {"", "log.Fatalf"},
+		"log.Panic":               {"", "log.Panicf"},
+		"log.Panicln":             {"", "log.Panicf"},
+		"log.Print":               {"", "log.Printf"},
+		"log.Println":             {"", "log.Printf"},
+	}
+)
+
+func run(pass *analysis.Pass) (any, error) {
+	fmtPrintf := func(node ast.Node) {
+		m, ok := code.Match(pass, checkPrintSprintQ, node)
+		if !ok {
+			return
+		}
+
+		name := m.State["fn"].(*types.Func).Name()
+		var msg string
+		switch name {
+		case "Print", "Fprint", "Sprint":
+			newname := name + "f"
+			msg = fmt.Sprintf("should use fmt.%s instead of fmt.%s(fmt.Sprintf(...))", newname, name)
+		case "Println", "Fprintln", "Sprintln":
+			if _, ok := m.State["f"].(*ast.BasicLit); !ok {
+				// This may be an instance of
+				// fmt.Println(fmt.Sprintf(arg, ...)) where arg is an
+				// externally provided format string and the caller
+				// cannot guarantee that the format string ends with a
+				// newline.
+				return
+			}
+			newname := name[:len(name)-2] + "f"
+			msg = fmt.Sprintf("should use fmt.%s instead of fmt.%s(fmt.Sprintf(...)) (but don't forget the newline)", newname, name)
+		}
+		report.Report(pass, node, msg,
+			report.FilterGenerated())
+	}
+
+	methSprintf := func(node ast.Node) {
+		m, ok := code.Match(pass, checkTestingErrorSprintfQ, node)
+		if !ok {
+			return
+		}
+		mapped, ok := checkSprintfMapping[code.CallName(pass, node.(*ast.CallExpr))]
+		if !ok {
+			return
+		}
+
+		// Ensure that Errorf/Fatalf refer to the right method
+		recvTV, ok := pass.TypesInfo.Types[m.State["recv"].(ast.Expr)]
+		if !ok {
+			return
+		}
+		obj, _, _ := types.LookupFieldOrMethod(recvTV.Type, recvTV.Addressable(), nil, mapped.alternative)
+		f, ok := obj.(*types.Func)
+		if !ok {
+			return
+		}
+		if typeutil.FuncName(f) != mapped.recv+"."+mapped.alternative {
+			return
+		}
+
+		alt := &ast.SelectorExpr{
+			X:   m.State["recv"].(ast.Expr),
+			Sel: &ast.Ident{Name: mapped.alternative},
+		}
+		report.Report(pass, node, fmt.Sprintf("should use %s(...) instead of %s(fmt.Sprintf(...))", report.Render(pass, alt), report.Render(pass, m.State["sel"].(*ast.SelectorExpr))))
+	}
+
+	pkgSprintf := func(node ast.Node) {
+		_, ok := code.Match(pass, checkLogSprintfQ, node)
+		if !ok {
+			return
+		}
+		callName := code.CallName(pass, node.(*ast.CallExpr))
+		mapped, ok := checkSprintfMapping[callName]
+		if !ok {
+			return
+		}
+		report.Report(pass, node, fmt.Sprintf("should use %s(...) instead of %s(fmt.Sprintf(...))", mapped.alternative, callName))
+	}
+
+	fn := func(node ast.Node) {
+		fmtPrintf(node)
+		// TODO(dh): add suggested fixes
+		methSprintf(node)
+		pkgSprintf(node)
+	}
+	if !code.CouldMatchAny(pass, checkLogSprintfQ, checkPrintSprintQ, checkTestingErrorSprintfQ) {
+		return nil, nil
+	}
+	code.Preorder(pass, fn, (*ast.CallExpr)(nil))
+	return nil, nil
+}