| 1 | // Copyright 2010 The Go Authors. All rights reserved. |
|---|---|
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // Package printf defines an Analyzer that checks consistency |
| 6 | // of Printf format strings and arguments. |
| 7 | package printf |
| 8 | |
| 9 | import ( |
| 10 | "bytes" |
| 11 | "fmt" |
| 12 | "go/ast" |
| 13 | "go/constant" |
| 14 | "go/token" |
| 15 | "go/types" |
| 16 | "reflect" |
| 17 | "regexp" |
| 18 | "sort" |
| 19 | "strconv" |
| 20 | "strings" |
| 21 | "unicode/utf8" |
| 22 | |
| 23 | "golang.org/x/tools/go/analysis" |
| 24 | "golang.org/x/tools/go/analysis/passes/inspect" |
| 25 | "golang.org/x/tools/go/analysis/passes/internal/analysisutil" |
| 26 | "golang.org/x/tools/go/ast/inspector" |
| 27 | "golang.org/x/tools/go/types/typeutil" |
| 28 | "golang.org/x/tools/internal/typeparams" |
| 29 | ) |
| 30 | |
| 31 | func init() { |
| 32 | Analyzer.Flags.Var(isPrint, "funcs", "comma-separated list of print function names to check") |
| 33 | } |
| 34 | |
| 35 | var Analyzer = &analysis.Analyzer{ |
| 36 | Name: "printf", |
| 37 | Doc: Doc, |
| 38 | Requires: []*analysis.Analyzer{inspect.Analyzer}, |
| 39 | Run: run, |
| 40 | ResultType: reflect.TypeOf((*Result)(nil)), |
| 41 | FactTypes: []analysis.Fact{new(isWrapper)}, |
| 42 | } |
| 43 | |
| 44 | const Doc = `check consistency of Printf format strings and arguments |
| 45 | |
| 46 | The check applies to known functions (for example, those in package fmt) |
| 47 | as well as any detected wrappers of known functions. |
| 48 | |
| 49 | A function that wants to avail itself of printf checking but is not |
| 50 | found by this analyzer's heuristics (for example, due to use of |
| 51 | dynamic calls) can insert a bogus call: |
| 52 | |
| 53 | if false { |
| 54 | _ = fmt.Sprintf(format, args...) // enable printf checking |
| 55 | } |
| 56 | |
| 57 | The -funcs flag specifies a comma-separated list of names of additional |
| 58 | known formatting functions or methods. If the name contains a period, |
| 59 | it must denote a specific function using one of the following forms: |
| 60 | |
| 61 | dir/pkg.Function |
| 62 | dir/pkg.Type.Method |
| 63 | (*dir/pkg.Type).Method |
| 64 | |
| 65 | Otherwise the name is interpreted as a case-insensitive unqualified |
| 66 | identifier such as "errorf". Either way, if a listed name ends in f, the |
| 67 | function is assumed to be Printf-like, taking a format string before the |
| 68 | argument list. Otherwise it is assumed to be Print-like, taking a list |
| 69 | of arguments with no format string. |
| 70 | ` |
| 71 | |
| 72 | // Kind is a kind of fmt function behavior. |
| 73 | type Kind int |
| 74 | |
| 75 | const ( |
| 76 | KindNone Kind = iota // not a fmt wrapper function |
| 77 | KindPrint // function behaves like fmt.Print |
| 78 | KindPrintf // function behaves like fmt.Printf |
| 79 | KindErrorf // function behaves like fmt.Errorf |
| 80 | ) |
| 81 | |
| 82 | func (kind Kind) String() string { |
| 83 | switch kind { |
| 84 | case KindPrint: |
| 85 | return "print" |
| 86 | case KindPrintf: |
| 87 | return "printf" |
| 88 | case KindErrorf: |
| 89 | return "errorf" |
| 90 | } |
| 91 | return "" |
| 92 | } |
| 93 | |
| 94 | // Result is the printf analyzer's result type. Clients may query the result |
| 95 | // to learn whether a function behaves like fmt.Print or fmt.Printf. |
| 96 | type Result struct { |
| 97 | funcs map[*types.Func]Kind |
| 98 | } |
| 99 | |
| 100 | // Kind reports whether fn behaves like fmt.Print or fmt.Printf. |
| 101 | func (r *Result) Kind(fn *types.Func) Kind { |
| 102 | _, ok := isPrint[fn.FullName()] |
| 103 | if !ok { |
| 104 | // Next look up just "printf", for use with -printf.funcs. |
| 105 | _, ok = isPrint[strings.ToLower(fn.Name())] |
| 106 | } |
| 107 | if ok { |
| 108 | if strings.HasSuffix(fn.Name(), "f") { |
| 109 | return KindPrintf |
| 110 | } else { |
| 111 | return KindPrint |
| 112 | } |
| 113 | } |
| 114 | |
| 115 | return r.funcs[fn] |
| 116 | } |
| 117 | |
| 118 | // isWrapper is a fact indicating that a function is a print or printf wrapper. |
| 119 | type isWrapper struct{ Kind Kind } |
| 120 | |
| 121 | func (f *isWrapper) AFact() {} |
| 122 | |
| 123 | func (f *isWrapper) String() string { |
| 124 | switch f.Kind { |
| 125 | case KindPrintf: |
| 126 | return "printfWrapper" |
| 127 | case KindPrint: |
| 128 | return "printWrapper" |
| 129 | case KindErrorf: |
| 130 | return "errorfWrapper" |
| 131 | default: |
| 132 | return "unknownWrapper" |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | func run(pass *analysis.Pass) (interface{}, error) { |
| 137 | res := &Result{ |
| 138 | funcs: make(map[*types.Func]Kind), |
| 139 | } |
| 140 | findPrintfLike(pass, res) |
| 141 | checkCall(pass) |
| 142 | return res, nil |
| 143 | } |
| 144 | |
| 145 | type printfWrapper struct { |
| 146 | obj *types.Func |
| 147 | fdecl *ast.FuncDecl |
| 148 | format *types.Var |
| 149 | args *types.Var |
| 150 | callers []printfCaller |
| 151 | failed bool // if true, not a printf wrapper |
| 152 | } |
| 153 | |
| 154 | type printfCaller struct { |
| 155 | w *printfWrapper |
| 156 | call *ast.CallExpr |
| 157 | } |
| 158 | |
| 159 | // maybePrintfWrapper decides whether decl (a declared function) may be a wrapper |
| 160 | // around a fmt.Printf or fmt.Print function. If so it returns a printfWrapper |
| 161 | // function describing the declaration. Later processing will analyze the |
| 162 | // graph of potential printf wrappers to pick out the ones that are true wrappers. |
| 163 | // A function may be a Printf or Print wrapper if its last argument is ...interface{}. |
| 164 | // If the next-to-last argument is a string, then this may be a Printf wrapper. |
| 165 | // Otherwise it may be a Print wrapper. |
| 166 | func maybePrintfWrapper(info *types.Info, decl ast.Decl) *printfWrapper { |
| 167 | // Look for functions with final argument type ...interface{}. |
| 168 | fdecl, ok := decl.(*ast.FuncDecl) |
| 169 | if !ok || fdecl.Body == nil { |
| 170 | return nil |
| 171 | } |
| 172 | fn, ok := info.Defs[fdecl.Name].(*types.Func) |
| 173 | // Type information may be incomplete. |
| 174 | if !ok { |
| 175 | return nil |
| 176 | } |
| 177 | |
| 178 | sig := fn.Type().(*types.Signature) |
| 179 | if !sig.Variadic() { |
| 180 | return nil // not variadic |
| 181 | } |
| 182 | |
| 183 | params := sig.Params() |
| 184 | nparams := params.Len() // variadic => nonzero |
| 185 | |
| 186 | args := params.At(nparams - 1) |
| 187 | iface, ok := args.Type().(*types.Slice).Elem().(*types.Interface) |
| 188 | if !ok || !iface.Empty() { |
| 189 | return nil // final (args) param is not ...interface{} |
| 190 | } |
| 191 | |
| 192 | // Is second last param 'format string'? |
| 193 | var format *types.Var |
| 194 | if nparams >= 2 { |
| 195 | if p := params.At(nparams - 2); p.Type() == types.Typ[types.String] { |
| 196 | format = p |
| 197 | } |
| 198 | } |
| 199 | |
| 200 | return &printfWrapper{ |
| 201 | obj: fn, |
| 202 | fdecl: fdecl, |
| 203 | format: format, |
| 204 | args: args, |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | // findPrintfLike scans the entire package to find printf-like functions. |
| 209 | func findPrintfLike(pass *analysis.Pass, res *Result) (interface{}, error) { |
| 210 | // Gather potential wrappers and call graph between them. |
| 211 | byObj := make(map[*types.Func]*printfWrapper) |
| 212 | var wrappers []*printfWrapper |
| 213 | for _, file := range pass.Files { |
| 214 | for _, decl := range file.Decls { |
| 215 | w := maybePrintfWrapper(pass.TypesInfo, decl) |
| 216 | if w == nil { |
| 217 | continue |
| 218 | } |
| 219 | byObj[w.obj] = w |
| 220 | wrappers = append(wrappers, w) |
| 221 | } |
| 222 | } |
| 223 | |
| 224 | // Walk the graph to figure out which are really printf wrappers. |
| 225 | for _, w := range wrappers { |
| 226 | // Scan function for calls that could be to other printf-like functions. |
| 227 | ast.Inspect(w.fdecl.Body, func(n ast.Node) bool { |
| 228 | if w.failed { |
| 229 | return false |
| 230 | } |
| 231 | |
| 232 | // TODO: Relax these checks; issue 26555. |
| 233 | if assign, ok := n.(*ast.AssignStmt); ok { |
| 234 | for _, lhs := range assign.Lhs { |
| 235 | if match(pass.TypesInfo, lhs, w.format) || |
| 236 | match(pass.TypesInfo, lhs, w.args) { |
| 237 | // Modifies the format |
| 238 | // string or args in |
| 239 | // some way, so not a |
| 240 | // simple wrapper. |
| 241 | w.failed = true |
| 242 | return false |
| 243 | } |
| 244 | } |
| 245 | } |
| 246 | if un, ok := n.(*ast.UnaryExpr); ok && un.Op == token.AND { |
| 247 | if match(pass.TypesInfo, un.X, w.format) || |
| 248 | match(pass.TypesInfo, un.X, w.args) { |
| 249 | // Taking the address of the |
| 250 | // format string or args, |
| 251 | // so not a simple wrapper. |
| 252 | w.failed = true |
| 253 | return false |
| 254 | } |
| 255 | } |
| 256 | |
| 257 | call, ok := n.(*ast.CallExpr) |
| 258 | if !ok || len(call.Args) == 0 || !match(pass.TypesInfo, call.Args[len(call.Args)-1], w.args) { |
| 259 | return true |
| 260 | } |
| 261 | |
| 262 | fn, kind := printfNameAndKind(pass, call) |
| 263 | if kind != 0 { |
| 264 | checkPrintfFwd(pass, w, call, kind, res) |
| 265 | return true |
| 266 | } |
| 267 | |
| 268 | // If the call is to another function in this package, |
| 269 | // maybe we will find out it is printf-like later. |
| 270 | // Remember this call for later checking. |
| 271 | if fn != nil && fn.Pkg() == pass.Pkg && byObj[fn] != nil { |
| 272 | callee := byObj[fn] |
| 273 | callee.callers = append(callee.callers, printfCaller{w, call}) |
| 274 | } |
| 275 | |
| 276 | return true |
| 277 | }) |
| 278 | } |
| 279 | return nil, nil |
| 280 | } |
| 281 | |
| 282 | func match(info *types.Info, arg ast.Expr, param *types.Var) bool { |
| 283 | id, ok := arg.(*ast.Ident) |
| 284 | return ok && info.ObjectOf(id) == param |
| 285 | } |
| 286 | |
| 287 | // checkPrintfFwd checks that a printf-forwarding wrapper is forwarding correctly. |
| 288 | // It diagnoses writing fmt.Printf(format, args) instead of fmt.Printf(format, args...). |
| 289 | func checkPrintfFwd(pass *analysis.Pass, w *printfWrapper, call *ast.CallExpr, kind Kind, res *Result) { |
| 290 | matched := kind == KindPrint || |
| 291 | kind != KindNone && len(call.Args) >= 2 && match(pass.TypesInfo, call.Args[len(call.Args)-2], w.format) |
| 292 | if !matched { |
| 293 | return |
| 294 | } |
| 295 | |
| 296 | if !call.Ellipsis.IsValid() { |
| 297 | typ, ok := pass.TypesInfo.Types[call.Fun].Type.(*types.Signature) |
| 298 | if !ok { |
| 299 | return |
| 300 | } |
| 301 | if len(call.Args) > typ.Params().Len() { |
| 302 | // If we're passing more arguments than what the |
| 303 | // print/printf function can take, adding an ellipsis |
| 304 | // would break the program. For example: |
| 305 | // |
| 306 | // func foo(arg1 string, arg2 ...interface{} { |
| 307 | // fmt.Printf("%s %v", arg1, arg2) |
| 308 | // } |
| 309 | return |
| 310 | } |
| 311 | desc := "printf" |
| 312 | if kind == KindPrint { |
| 313 | desc = "print" |
| 314 | } |
| 315 | pass.ReportRangef(call, "missing ... in args forwarded to %s-like function", desc) |
| 316 | return |
| 317 | } |
| 318 | fn := w.obj |
| 319 | var fact isWrapper |
| 320 | if !pass.ImportObjectFact(fn, &fact) { |
| 321 | fact.Kind = kind |
| 322 | pass.ExportObjectFact(fn, &fact) |
| 323 | res.funcs[fn] = kind |
| 324 | for _, caller := range w.callers { |
| 325 | checkPrintfFwd(pass, caller.w, caller.call, kind, res) |
| 326 | } |
| 327 | } |
| 328 | } |
| 329 | |
| 330 | // isPrint records the print functions. |
| 331 | // If a key ends in 'f' then it is assumed to be a formatted print. |
| 332 | // |
| 333 | // Keys are either values returned by (*types.Func).FullName, |
| 334 | // or case-insensitive identifiers such as "errorf". |
| 335 | // |
| 336 | // The -funcs flag adds to this set. |
| 337 | // |
| 338 | // The set below includes facts for many important standard library |
| 339 | // functions, even though the analysis is capable of deducing that, for |
| 340 | // example, fmt.Printf forwards to fmt.Fprintf. We avoid relying on the |
| 341 | // driver applying analyzers to standard packages because "go vet" does |
| 342 | // not do so with gccgo, and nor do some other build systems. |
| 343 | // TODO(adonovan): eliminate the redundant facts once this restriction |
| 344 | // is lifted. |
| 345 | var isPrint = stringSet{ |
| 346 | "fmt.Errorf": true, |
| 347 | "fmt.Fprint": true, |
| 348 | "fmt.Fprintf": true, |
| 349 | "fmt.Fprintln": true, |
| 350 | "fmt.Print": true, |
| 351 | "fmt.Printf": true, |
| 352 | "fmt.Println": true, |
| 353 | "fmt.Sprint": true, |
| 354 | "fmt.Sprintf": true, |
| 355 | "fmt.Sprintln": true, |
| 356 | |
| 357 | "runtime/trace.Logf": true, |
| 358 | |
| 359 | "log.Print": true, |
| 360 | "log.Printf": true, |
| 361 | "log.Println": true, |
| 362 | "log.Fatal": true, |
| 363 | "log.Fatalf": true, |
| 364 | "log.Fatalln": true, |
| 365 | "log.Panic": true, |
| 366 | "log.Panicf": true, |
| 367 | "log.Panicln": true, |
| 368 | "(*log.Logger).Fatal": true, |
| 369 | "(*log.Logger).Fatalf": true, |
| 370 | "(*log.Logger).Fatalln": true, |
| 371 | "(*log.Logger).Panic": true, |
| 372 | "(*log.Logger).Panicf": true, |
| 373 | "(*log.Logger).Panicln": true, |
| 374 | "(*log.Logger).Print": true, |
| 375 | "(*log.Logger).Printf": true, |
| 376 | "(*log.Logger).Println": true, |
| 377 | |
| 378 | "(*testing.common).Error": true, |
| 379 | "(*testing.common).Errorf": true, |
| 380 | "(*testing.common).Fatal": true, |
| 381 | "(*testing.common).Fatalf": true, |
| 382 | "(*testing.common).Log": true, |
| 383 | "(*testing.common).Logf": true, |
| 384 | "(*testing.common).Skip": true, |
| 385 | "(*testing.common).Skipf": true, |
| 386 | // *testing.T and B are detected by induction, but testing.TB is |
| 387 | // an interface and the inference can't follow dynamic calls. |
| 388 | "(testing.TB).Error": true, |
| 389 | "(testing.TB).Errorf": true, |
| 390 | "(testing.TB).Fatal": true, |
| 391 | "(testing.TB).Fatalf": true, |
| 392 | "(testing.TB).Log": true, |
| 393 | "(testing.TB).Logf": true, |
| 394 | "(testing.TB).Skip": true, |
| 395 | "(testing.TB).Skipf": true, |
| 396 | } |
| 397 | |
| 398 | // formatString returns the format string argument and its index within |
| 399 | // the given printf-like call expression. |
| 400 | // |
| 401 | // The last parameter before variadic arguments is assumed to be |
| 402 | // a format string. |
| 403 | // |
| 404 | // The first string literal or string constant is assumed to be a format string |
| 405 | // if the call's signature cannot be determined. |
| 406 | // |
| 407 | // If it cannot find any format string parameter, it returns ("", -1). |
| 408 | func formatString(pass *analysis.Pass, call *ast.CallExpr) (format string, idx int) { |
| 409 | typ := pass.TypesInfo.Types[call.Fun].Type |
| 410 | if typ != nil { |
| 411 | if sig, ok := typ.(*types.Signature); ok { |
| 412 | if !sig.Variadic() { |
| 413 | // Skip checking non-variadic functions. |
| 414 | return "", -1 |
| 415 | } |
| 416 | idx := sig.Params().Len() - 2 |
| 417 | if idx < 0 { |
| 418 | // Skip checking variadic functions without |
| 419 | // fixed arguments. |
| 420 | return "", -1 |
| 421 | } |
| 422 | s, ok := stringConstantArg(pass, call, idx) |
| 423 | if !ok { |
| 424 | // The last argument before variadic args isn't a string. |
| 425 | return "", -1 |
| 426 | } |
| 427 | return s, idx |
| 428 | } |
| 429 | } |
| 430 | |
| 431 | // Cannot determine call's signature. Fall back to scanning for the first |
| 432 | // string constant in the call. |
| 433 | for idx := range call.Args { |
| 434 | if s, ok := stringConstantArg(pass, call, idx); ok { |
| 435 | return s, idx |
| 436 | } |
| 437 | if pass.TypesInfo.Types[call.Args[idx]].Type == types.Typ[types.String] { |
| 438 | // Skip checking a call with a non-constant format |
| 439 | // string argument, since its contents are unavailable |
| 440 | // for validation. |
| 441 | return "", -1 |
| 442 | } |
| 443 | } |
| 444 | return "", -1 |
| 445 | } |
| 446 | |
| 447 | // stringConstantArg returns call's string constant argument at the index idx. |
| 448 | // |
| 449 | // ("", false) is returned if call's argument at the index idx isn't a string |
| 450 | // constant. |
| 451 | func stringConstantArg(pass *analysis.Pass, call *ast.CallExpr, idx int) (string, bool) { |
| 452 | if idx >= len(call.Args) { |
| 453 | return "", false |
| 454 | } |
| 455 | return stringConstantExpr(pass, call.Args[idx]) |
| 456 | } |
| 457 | |
| 458 | // stringConstantExpr returns expression's string constant value. |
| 459 | // |
| 460 | // ("", false) is returned if expression isn't a string |
| 461 | // constant. |
| 462 | func stringConstantExpr(pass *analysis.Pass, expr ast.Expr) (string, bool) { |
| 463 | lit := pass.TypesInfo.Types[expr].Value |
| 464 | if lit != nil && lit.Kind() == constant.String { |
| 465 | return constant.StringVal(lit), true |
| 466 | } |
| 467 | return "", false |
| 468 | } |
| 469 | |
| 470 | // checkCall triggers the print-specific checks if the call invokes a print function. |
| 471 | func checkCall(pass *analysis.Pass) { |
| 472 | inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector) |
| 473 | nodeFilter := []ast.Node{ |
| 474 | (*ast.CallExpr)(nil), |
| 475 | } |
| 476 | inspect.Preorder(nodeFilter, func(n ast.Node) { |
| 477 | call := n.(*ast.CallExpr) |
| 478 | fn, kind := printfNameAndKind(pass, call) |
| 479 | switch kind { |
| 480 | case KindPrintf, KindErrorf: |
| 481 | checkPrintf(pass, kind, call, fn) |
| 482 | case KindPrint: |
| 483 | checkPrint(pass, call, fn) |
| 484 | } |
| 485 | }) |
| 486 | } |
| 487 | |
| 488 | func printfNameAndKind(pass *analysis.Pass, call *ast.CallExpr) (fn *types.Func, kind Kind) { |
| 489 | fn, _ = typeutil.Callee(pass.TypesInfo, call).(*types.Func) |
| 490 | if fn == nil { |
| 491 | return nil, 0 |
| 492 | } |
| 493 | |
| 494 | _, ok := isPrint[fn.FullName()] |
| 495 | if !ok { |
| 496 | // Next look up just "printf", for use with -printf.funcs. |
| 497 | _, ok = isPrint[strings.ToLower(fn.Name())] |
| 498 | } |
| 499 | if ok { |
| 500 | if fn.FullName() == "fmt.Errorf" { |
| 501 | kind = KindErrorf |
| 502 | } else if strings.HasSuffix(fn.Name(), "f") { |
| 503 | kind = KindPrintf |
| 504 | } else { |
| 505 | kind = KindPrint |
| 506 | } |
| 507 | return fn, kind |
| 508 | } |
| 509 | |
| 510 | var fact isWrapper |
| 511 | if pass.ImportObjectFact(fn, &fact) { |
| 512 | return fn, fact.Kind |
| 513 | } |
| 514 | |
| 515 | return fn, KindNone |
| 516 | } |
| 517 | |
| 518 | // isFormatter reports whether t could satisfy fmt.Formatter. |
| 519 | // The only interface method to look for is "Format(State, rune)". |
| 520 | func isFormatter(typ types.Type) bool { |
| 521 | // If the type is an interface, the value it holds might satisfy fmt.Formatter. |
| 522 | if _, ok := typ.Underlying().(*types.Interface); ok { |
| 523 | // Don't assume type parameters could be formatters. With the greater |
| 524 | // expressiveness of constraint interface syntax we expect more type safety |
| 525 | // when using type parameters. |
| 526 | if !typeparams.IsTypeParam(typ) { |
| 527 | return true |
| 528 | } |
| 529 | } |
| 530 | obj, _, _ := types.LookupFieldOrMethod(typ, false, nil, "Format") |
| 531 | fn, ok := obj.(*types.Func) |
| 532 | if !ok { |
| 533 | return false |
| 534 | } |
| 535 | sig := fn.Type().(*types.Signature) |
| 536 | return sig.Params().Len() == 2 && |
| 537 | sig.Results().Len() == 0 && |
| 538 | isNamed(sig.Params().At(0).Type(), "fmt", "State") && |
| 539 | types.Identical(sig.Params().At(1).Type(), types.Typ[types.Rune]) |
| 540 | } |
| 541 | |
| 542 | func isNamed(T types.Type, pkgpath, name string) bool { |
| 543 | named, ok := T.(*types.Named) |
| 544 | return ok && named.Obj().Pkg().Path() == pkgpath && named.Obj().Name() == name |
| 545 | } |
| 546 | |
| 547 | // formatState holds the parsed representation of a printf directive such as "%3.*[4]d". |
| 548 | // It is constructed by parsePrintfVerb. |
| 549 | type formatState struct { |
| 550 | verb rune // the format verb: 'd' for "%d" |
| 551 | format string // the full format directive from % through verb, "%.3d". |
| 552 | name string // Printf, Sprintf etc. |
| 553 | flags []byte // the list of # + etc. |
| 554 | argNums []int // the successive argument numbers that are consumed, adjusted to refer to actual arg in call |
| 555 | firstArg int // Index of first argument after the format in the Printf call. |
| 556 | // Used only during parse. |
| 557 | pass *analysis.Pass |
| 558 | call *ast.CallExpr |
| 559 | argNum int // Which argument we're expecting to format now. |
| 560 | hasIndex bool // Whether the argument is indexed. |
| 561 | indexPending bool // Whether we have an indexed argument that has not resolved. |
| 562 | nbytes int // number of bytes of the format string consumed. |
| 563 | } |
| 564 | |
| 565 | // checkPrintf checks a call to a formatted print routine such as Printf. |
| 566 | func checkPrintf(pass *analysis.Pass, kind Kind, call *ast.CallExpr, fn *types.Func) { |
| 567 | format, idx := formatString(pass, call) |
| 568 | if idx < 0 { |
| 569 | if false { |
| 570 | pass.Reportf(call.Lparen, "can't check non-constant format in call to %s", fn.FullName()) |
| 571 | } |
| 572 | return |
| 573 | } |
| 574 | |
| 575 | firstArg := idx + 1 // Arguments are immediately after format string. |
| 576 | if !strings.Contains(format, "%") { |
| 577 | if len(call.Args) > firstArg { |
| 578 | pass.Reportf(call.Lparen, "%s call has arguments but no formatting directives", fn.FullName()) |
| 579 | } |
| 580 | return |
| 581 | } |
| 582 | // Hard part: check formats against args. |
| 583 | argNum := firstArg |
| 584 | maxArgNum := firstArg |
| 585 | anyIndex := false |
| 586 | for i, w := 0, 0; i < len(format); i += w { |
| 587 | w = 1 |
| 588 | if format[i] != '%' { |
| 589 | continue |
| 590 | } |
| 591 | state := parsePrintfVerb(pass, call, fn.FullName(), format[i:], firstArg, argNum) |
| 592 | if state == nil { |
| 593 | return |
| 594 | } |
| 595 | w = len(state.format) |
| 596 | if !okPrintfArg(pass, call, state) { // One error per format is enough. |
| 597 | return |
| 598 | } |
| 599 | if state.hasIndex { |
| 600 | anyIndex = true |
| 601 | } |
| 602 | if state.verb == 'w' { |
| 603 | switch kind { |
| 604 | case KindNone, KindPrint, KindPrintf: |
| 605 | pass.Reportf(call.Pos(), "%s does not support error-wrapping directive %%w", state.name) |
| 606 | return |
| 607 | } |
| 608 | } |
| 609 | if len(state.argNums) > 0 { |
| 610 | // Continue with the next sequential argument. |
| 611 | argNum = state.argNums[len(state.argNums)-1] + 1 |
| 612 | } |
| 613 | for _, n := range state.argNums { |
| 614 | if n >= maxArgNum { |
| 615 | maxArgNum = n + 1 |
| 616 | } |
| 617 | } |
| 618 | } |
| 619 | // Dotdotdot is hard. |
| 620 | if call.Ellipsis.IsValid() && maxArgNum >= len(call.Args)-1 { |
| 621 | return |
| 622 | } |
| 623 | // If any formats are indexed, extra arguments are ignored. |
| 624 | if anyIndex { |
| 625 | return |
| 626 | } |
| 627 | // There should be no leftover arguments. |
| 628 | if maxArgNum != len(call.Args) { |
| 629 | expect := maxArgNum - firstArg |
| 630 | numArgs := len(call.Args) - firstArg |
| 631 | pass.ReportRangef(call, "%s call needs %v but has %v", fn.FullName(), count(expect, "arg"), count(numArgs, "arg")) |
| 632 | } |
| 633 | } |
| 634 | |
| 635 | // parseFlags accepts any printf flags. |
| 636 | func (s *formatState) parseFlags() { |
| 637 | for s.nbytes < len(s.format) { |
| 638 | switch c := s.format[s.nbytes]; c { |
| 639 | case '#', '0', '+', '-', ' ': |
| 640 | s.flags = append(s.flags, c) |
| 641 | s.nbytes++ |
| 642 | default: |
| 643 | return |
| 644 | } |
| 645 | } |
| 646 | } |
| 647 | |
| 648 | // scanNum advances through a decimal number if present. |
| 649 | func (s *formatState) scanNum() { |
| 650 | for ; s.nbytes < len(s.format); s.nbytes++ { |
| 651 | c := s.format[s.nbytes] |
| 652 | if c < '0' || '9' < c { |
| 653 | return |
| 654 | } |
| 655 | } |
| 656 | } |
| 657 | |
| 658 | // parseIndex scans an index expression. It returns false if there is a syntax error. |
| 659 | func (s *formatState) parseIndex() bool { |
| 660 | if s.nbytes == len(s.format) || s.format[s.nbytes] != '[' { |
| 661 | return true |
| 662 | } |
| 663 | // Argument index present. |
| 664 | s.nbytes++ // skip '[' |
| 665 | start := s.nbytes |
| 666 | s.scanNum() |
| 667 | ok := true |
| 668 | if s.nbytes == len(s.format) || s.nbytes == start || s.format[s.nbytes] != ']' { |
| 669 | ok = false // syntax error is either missing "]" or invalid index. |
| 670 | s.nbytes = strings.Index(s.format[start:], "]") |
| 671 | if s.nbytes < 0 { |
| 672 | s.pass.ReportRangef(s.call, "%s format %s is missing closing ]", s.name, s.format) |
| 673 | return false |
| 674 | } |
| 675 | s.nbytes = s.nbytes + start |
| 676 | } |
| 677 | arg32, err := strconv.ParseInt(s.format[start:s.nbytes], 10, 32) |
| 678 | if err != nil || !ok || arg32 <= 0 || arg32 > int64(len(s.call.Args)-s.firstArg) { |
| 679 | s.pass.ReportRangef(s.call, "%s format has invalid argument index [%s]", s.name, s.format[start:s.nbytes]) |
| 680 | return false |
| 681 | } |
| 682 | s.nbytes++ // skip ']' |
| 683 | arg := int(arg32) |
| 684 | arg += s.firstArg - 1 // We want to zero-index the actual arguments. |
| 685 | s.argNum = arg |
| 686 | s.hasIndex = true |
| 687 | s.indexPending = true |
| 688 | return true |
| 689 | } |
| 690 | |
| 691 | // parseNum scans a width or precision (or *). It returns false if there's a bad index expression. |
| 692 | func (s *formatState) parseNum() bool { |
| 693 | if s.nbytes < len(s.format) && s.format[s.nbytes] == '*' { |
| 694 | if s.indexPending { // Absorb it. |
| 695 | s.indexPending = false |
| 696 | } |
| 697 | s.nbytes++ |
| 698 | s.argNums = append(s.argNums, s.argNum) |
| 699 | s.argNum++ |
| 700 | } else { |
| 701 | s.scanNum() |
| 702 | } |
| 703 | return true |
| 704 | } |
| 705 | |
| 706 | // parsePrecision scans for a precision. It returns false if there's a bad index expression. |
| 707 | func (s *formatState) parsePrecision() bool { |
| 708 | // If there's a period, there may be a precision. |
| 709 | if s.nbytes < len(s.format) && s.format[s.nbytes] == '.' { |
| 710 | s.flags = append(s.flags, '.') // Treat precision as a flag. |
| 711 | s.nbytes++ |
| 712 | if !s.parseIndex() { |
| 713 | return false |
| 714 | } |
| 715 | if !s.parseNum() { |
| 716 | return false |
| 717 | } |
| 718 | } |
| 719 | return true |
| 720 | } |
| 721 | |
| 722 | // parsePrintfVerb looks the formatting directive that begins the format string |
| 723 | // and returns a formatState that encodes what the directive wants, without looking |
| 724 | // at the actual arguments present in the call. The result is nil if there is an error. |
| 725 | func parsePrintfVerb(pass *analysis.Pass, call *ast.CallExpr, name, format string, firstArg, argNum int) *formatState { |
| 726 | state := &formatState{ |
| 727 | format: format, |
| 728 | name: name, |
| 729 | flags: make([]byte, 0, 5), |
| 730 | argNum: argNum, |
| 731 | argNums: make([]int, 0, 1), |
| 732 | nbytes: 1, // There's guaranteed to be a percent sign. |
| 733 | firstArg: firstArg, |
| 734 | pass: pass, |
| 735 | call: call, |
| 736 | } |
| 737 | // There may be flags. |
| 738 | state.parseFlags() |
| 739 | // There may be an index. |
| 740 | if !state.parseIndex() { |
| 741 | return nil |
| 742 | } |
| 743 | // There may be a width. |
| 744 | if !state.parseNum() { |
| 745 | return nil |
| 746 | } |
| 747 | // There may be a precision. |
| 748 | if !state.parsePrecision() { |
| 749 | return nil |
| 750 | } |
| 751 | // Now a verb, possibly prefixed by an index (which we may already have). |
| 752 | if !state.indexPending && !state.parseIndex() { |
| 753 | return nil |
| 754 | } |
| 755 | if state.nbytes == len(state.format) { |
| 756 | pass.ReportRangef(call.Fun, "%s format %s is missing verb at end of string", name, state.format) |
| 757 | return nil |
| 758 | } |
| 759 | verb, w := utf8.DecodeRuneInString(state.format[state.nbytes:]) |
| 760 | state.verb = verb |
| 761 | state.nbytes += w |
| 762 | if verb != '%' { |
| 763 | state.argNums = append(state.argNums, state.argNum) |
| 764 | } |
| 765 | state.format = state.format[:state.nbytes] |
| 766 | return state |
| 767 | } |
| 768 | |
| 769 | // printfArgType encodes the types of expressions a printf verb accepts. It is a bitmask. |
| 770 | type printfArgType int |
| 771 | |
| 772 | const ( |
| 773 | argBool printfArgType = 1 << iota |
| 774 | argInt |
| 775 | argRune |
| 776 | argString |
| 777 | argFloat |
| 778 | argComplex |
| 779 | argPointer |
| 780 | argError |
| 781 | anyType printfArgType = ^0 |
| 782 | ) |
| 783 | |
| 784 | type printVerb struct { |
| 785 | verb rune // User may provide verb through Formatter; could be a rune. |
| 786 | flags string // known flags are all ASCII |
| 787 | typ printfArgType |
| 788 | } |
| 789 | |
| 790 | // Common flag sets for printf verbs. |
| 791 | const ( |
| 792 | noFlag = "" |
| 793 | numFlag = " -+.0" |
| 794 | sharpNumFlag = " -+.0#" |
| 795 | allFlags = " -+.0#" |
| 796 | ) |
| 797 | |
| 798 | // printVerbs identifies which flags are known to printf for each verb. |
| 799 | var printVerbs = []printVerb{ |
| 800 | // '-' is a width modifier, always valid. |
| 801 | // '.' is a precision for float, max width for strings. |
| 802 | // '+' is required sign for numbers, Go format for %v. |
| 803 | // '#' is alternate format for several verbs. |
| 804 | // ' ' is spacer for numbers |
| 805 | {'%', noFlag, 0}, |
| 806 | {'b', sharpNumFlag, argInt | argFloat | argComplex | argPointer}, |
| 807 | {'c', "-", argRune | argInt}, |
| 808 | {'d', numFlag, argInt | argPointer}, |
| 809 | {'e', sharpNumFlag, argFloat | argComplex}, |
| 810 | {'E', sharpNumFlag, argFloat | argComplex}, |
| 811 | {'f', sharpNumFlag, argFloat | argComplex}, |
| 812 | {'F', sharpNumFlag, argFloat | argComplex}, |
| 813 | {'g', sharpNumFlag, argFloat | argComplex}, |
| 814 | {'G', sharpNumFlag, argFloat | argComplex}, |
| 815 | {'o', sharpNumFlag, argInt | argPointer}, |
| 816 | {'O', sharpNumFlag, argInt | argPointer}, |
| 817 | {'p', "-#", argPointer}, |
| 818 | {'q', " -+.0#", argRune | argInt | argString}, |
| 819 | {'s', " -+.0", argString}, |
| 820 | {'t', "-", argBool}, |
| 821 | {'T', "-", anyType}, |
| 822 | {'U', "-#", argRune | argInt}, |
| 823 | {'v', allFlags, anyType}, |
| 824 | {'w', allFlags, argError}, |
| 825 | {'x', sharpNumFlag, argRune | argInt | argString | argPointer | argFloat | argComplex}, |
| 826 | {'X', sharpNumFlag, argRune | argInt | argString | argPointer | argFloat | argComplex}, |
| 827 | } |
| 828 | |
| 829 | // okPrintfArg compares the formatState to the arguments actually present, |
| 830 | // reporting any discrepancies it can discern. If the final argument is ellipsissed, |
| 831 | // there's little it can do for that. |
| 832 | func okPrintfArg(pass *analysis.Pass, call *ast.CallExpr, state *formatState) (ok bool) { |
| 833 | var v printVerb |
| 834 | found := false |
| 835 | // Linear scan is fast enough for a small list. |
| 836 | for _, v = range printVerbs { |
| 837 | if v.verb == state.verb { |
| 838 | found = true |
| 839 | break |
| 840 | } |
| 841 | } |
| 842 | |
| 843 | // Could current arg implement fmt.Formatter? |
| 844 | // Skip check for the %w verb, which requires an error. |
| 845 | formatter := false |
| 846 | if v.typ != argError && state.argNum < len(call.Args) { |
| 847 | if tv, ok := pass.TypesInfo.Types[call.Args[state.argNum]]; ok { |
| 848 | formatter = isFormatter(tv.Type) |
| 849 | } |
| 850 | } |
| 851 | |
| 852 | if !formatter { |
| 853 | if !found { |
| 854 | pass.ReportRangef(call, "%s format %s has unknown verb %c", state.name, state.format, state.verb) |
| 855 | return false |
| 856 | } |
| 857 | for _, flag := range state.flags { |
| 858 | // TODO: Disable complaint about '0' for Go 1.10. To be fixed properly in 1.11. |
| 859 | // See issues 23598 and 23605. |
| 860 | if flag == '0' { |
| 861 | continue |
| 862 | } |
| 863 | if !strings.ContainsRune(v.flags, rune(flag)) { |
| 864 | pass.ReportRangef(call, "%s format %s has unrecognized flag %c", state.name, state.format, flag) |
| 865 | return false |
| 866 | } |
| 867 | } |
| 868 | } |
| 869 | // Verb is good. If len(state.argNums)>trueArgs, we have something like %.*s and all |
| 870 | // but the final arg must be an integer. |
| 871 | trueArgs := 1 |
| 872 | if state.verb == '%' { |
| 873 | trueArgs = 0 |
| 874 | } |
| 875 | nargs := len(state.argNums) |
| 876 | for i := 0; i < nargs-trueArgs; i++ { |
| 877 | argNum := state.argNums[i] |
| 878 | if !argCanBeChecked(pass, call, i, state) { |
| 879 | return |
| 880 | } |
| 881 | arg := call.Args[argNum] |
| 882 | if reason, ok := matchArgType(pass, argInt, arg); !ok { |
| 883 | details := "" |
| 884 | if reason != "" { |
| 885 | details = " (" + reason + ")" |
| 886 | } |
| 887 | pass.ReportRangef(call, "%s format %s uses non-int %s%s as argument of *", state.name, state.format, analysisutil.Format(pass.Fset, arg), details) |
| 888 | return false |
| 889 | } |
| 890 | } |
| 891 | |
| 892 | if state.verb == '%' || formatter { |
| 893 | return true |
| 894 | } |
| 895 | argNum := state.argNums[len(state.argNums)-1] |
| 896 | if !argCanBeChecked(pass, call, len(state.argNums)-1, state) { |
| 897 | return false |
| 898 | } |
| 899 | arg := call.Args[argNum] |
| 900 | if isFunctionValue(pass, arg) && state.verb != 'p' && state.verb != 'T' { |
| 901 | pass.ReportRangef(call, "%s format %s arg %s is a func value, not called", state.name, state.format, analysisutil.Format(pass.Fset, arg)) |
| 902 | return false |
| 903 | } |
| 904 | if reason, ok := matchArgType(pass, v.typ, arg); !ok { |
| 905 | typeString := "" |
| 906 | if typ := pass.TypesInfo.Types[arg].Type; typ != nil { |
| 907 | typeString = typ.String() |
| 908 | } |
| 909 | details := "" |
| 910 | if reason != "" { |
| 911 | details = " (" + reason + ")" |
| 912 | } |
| 913 | pass.ReportRangef(call, "%s format %s has arg %s of wrong type %s%s, see also https://pkg.go.dev/fmt#hdr-Printing", state.name, state.format, analysisutil.Format(pass.Fset, arg), typeString, details) |
| 914 | return false |
| 915 | } |
| 916 | if v.typ&argString != 0 && v.verb != 'T' && !bytes.Contains(state.flags, []byte{'#'}) { |
| 917 | if methodName, ok := recursiveStringer(pass, arg); ok { |
| 918 | pass.ReportRangef(call, "%s format %s with arg %s causes recursive %s method call", state.name, state.format, analysisutil.Format(pass.Fset, arg), methodName) |
| 919 | return false |
| 920 | } |
| 921 | } |
| 922 | return true |
| 923 | } |
| 924 | |
| 925 | // recursiveStringer reports whether the argument e is a potential |
| 926 | // recursive call to stringer or is an error, such as t and &t in these examples: |
| 927 | // |
| 928 | // func (t *T) String() string { printf("%s", t) } |
| 929 | // func (t T) Error() string { printf("%s", t) } |
| 930 | // func (t T) String() string { printf("%s", &t) } |
| 931 | func recursiveStringer(pass *analysis.Pass, e ast.Expr) (string, bool) { |
| 932 | typ := pass.TypesInfo.Types[e].Type |
| 933 | |
| 934 | // It's unlikely to be a recursive stringer if it has a Format method. |
| 935 | if isFormatter(typ) { |
| 936 | return "", false |
| 937 | } |
| 938 | |
| 939 | // Does e allow e.String() or e.Error()? |
| 940 | strObj, _, _ := types.LookupFieldOrMethod(typ, false, pass.Pkg, "String") |
| 941 | strMethod, strOk := strObj.(*types.Func) |
| 942 | errObj, _, _ := types.LookupFieldOrMethod(typ, false, pass.Pkg, "Error") |
| 943 | errMethod, errOk := errObj.(*types.Func) |
| 944 | if !strOk && !errOk { |
| 945 | return "", false |
| 946 | } |
| 947 | |
| 948 | // inScope returns true if e is in the scope of f. |
| 949 | inScope := func(e ast.Expr, f *types.Func) bool { |
| 950 | return f.Scope() != nil && f.Scope().Contains(e.Pos()) |
| 951 | } |
| 952 | |
| 953 | // Is the expression e within the body of that String or Error method? |
| 954 | var method *types.Func |
| 955 | if strOk && strMethod.Pkg() == pass.Pkg && inScope(e, strMethod) { |
| 956 | method = strMethod |
| 957 | } else if errOk && errMethod.Pkg() == pass.Pkg && inScope(e, errMethod) { |
| 958 | method = errMethod |
| 959 | } else { |
| 960 | return "", false |
| 961 | } |
| 962 | |
| 963 | sig := method.Type().(*types.Signature) |
| 964 | if !isStringer(sig) { |
| 965 | return "", false |
| 966 | } |
| 967 | |
| 968 | // Is it the receiver r, or &r? |
| 969 | if u, ok := e.(*ast.UnaryExpr); ok && u.Op == token.AND { |
| 970 | e = u.X // strip off & from &r |
| 971 | } |
| 972 | if id, ok := e.(*ast.Ident); ok { |
| 973 | if pass.TypesInfo.Uses[id] == sig.Recv() { |
| 974 | return method.FullName(), true |
| 975 | } |
| 976 | } |
| 977 | return "", false |
| 978 | } |
| 979 | |
| 980 | // isStringer reports whether the method signature matches the String() definition in fmt.Stringer. |
| 981 | func isStringer(sig *types.Signature) bool { |
| 982 | return sig.Params().Len() == 0 && |
| 983 | sig.Results().Len() == 1 && |
| 984 | sig.Results().At(0).Type() == types.Typ[types.String] |
| 985 | } |
| 986 | |
| 987 | // isFunctionValue reports whether the expression is a function as opposed to a function call. |
| 988 | // It is almost always a mistake to print a function value. |
| 989 | func isFunctionValue(pass *analysis.Pass, e ast.Expr) bool { |
| 990 | if typ := pass.TypesInfo.Types[e].Type; typ != nil { |
| 991 | _, ok := typ.(*types.Signature) |
| 992 | return ok |
| 993 | } |
| 994 | return false |
| 995 | } |
| 996 | |
| 997 | // argCanBeChecked reports whether the specified argument is statically present; |
| 998 | // it may be beyond the list of arguments or in a terminal slice... argument, which |
| 999 | // means we can't see it. |
| 1000 | func argCanBeChecked(pass *analysis.Pass, call *ast.CallExpr, formatArg int, state *formatState) bool { |
| 1001 | argNum := state.argNums[formatArg] |
| 1002 | if argNum <= 0 { |
| 1003 | // Shouldn't happen, so catch it with prejudice. |
| 1004 | panic("negative arg num") |
| 1005 | } |
| 1006 | if argNum < len(call.Args)-1 { |
| 1007 | return true // Always OK. |
| 1008 | } |
| 1009 | if call.Ellipsis.IsValid() { |
| 1010 | return false // We just can't tell; there could be many more arguments. |
| 1011 | } |
| 1012 | if argNum < len(call.Args) { |
| 1013 | return true |
| 1014 | } |
| 1015 | // There are bad indexes in the format or there are fewer arguments than the format needs. |
| 1016 | // This is the argument number relative to the format: Printf("%s", "hi") will give 1 for the "hi". |
| 1017 | arg := argNum - state.firstArg + 1 // People think of arguments as 1-indexed. |
| 1018 | pass.ReportRangef(call, "%s format %s reads arg #%d, but call has %v", state.name, state.format, arg, count(len(call.Args)-state.firstArg, "arg")) |
| 1019 | return false |
| 1020 | } |
| 1021 | |
| 1022 | // printFormatRE is the regexp we match and report as a possible format string |
| 1023 | // in the first argument to unformatted prints like fmt.Print. |
| 1024 | // We exclude the space flag, so that printing a string like "x % y" is not reported as a format. |
| 1025 | var printFormatRE = regexp.MustCompile(`%` + flagsRE + numOptRE + `\.?` + numOptRE + indexOptRE + verbRE) |
| 1026 | |
| 1027 | const ( |
| 1028 | flagsRE = `[+\-#]*` |
| 1029 | indexOptRE = `(\[[0-9]+\])?` |
| 1030 | numOptRE = `([0-9]+|` + indexOptRE + `\*)?` |
| 1031 | verbRE = `[bcdefgopqstvxEFGTUX]` |
| 1032 | ) |
| 1033 | |
| 1034 | // checkPrint checks a call to an unformatted print routine such as Println. |
| 1035 | func checkPrint(pass *analysis.Pass, call *ast.CallExpr, fn *types.Func) { |
| 1036 | firstArg := 0 |
| 1037 | typ := pass.TypesInfo.Types[call.Fun].Type |
| 1038 | if typ == nil { |
| 1039 | // Skip checking functions with unknown type. |
| 1040 | return |
| 1041 | } |
| 1042 | if sig, ok := typ.(*types.Signature); ok { |
| 1043 | if !sig.Variadic() { |
| 1044 | // Skip checking non-variadic functions. |
| 1045 | return |
| 1046 | } |
| 1047 | params := sig.Params() |
| 1048 | firstArg = params.Len() - 1 |
| 1049 | |
| 1050 | typ := params.At(firstArg).Type() |
| 1051 | typ = typ.(*types.Slice).Elem() |
| 1052 | it, ok := typ.(*types.Interface) |
| 1053 | if !ok || !it.Empty() { |
| 1054 | // Skip variadic functions accepting non-interface{} args. |
| 1055 | return |
| 1056 | } |
| 1057 | } |
| 1058 | args := call.Args |
| 1059 | if len(args) <= firstArg { |
| 1060 | // Skip calls without variadic args. |
| 1061 | return |
| 1062 | } |
| 1063 | args = args[firstArg:] |
| 1064 | |
| 1065 | if firstArg == 0 { |
| 1066 | if sel, ok := call.Args[0].(*ast.SelectorExpr); ok { |
| 1067 | if x, ok := sel.X.(*ast.Ident); ok { |
| 1068 | if x.Name == "os" && strings.HasPrefix(sel.Sel.Name, "Std") { |
| 1069 | pass.ReportRangef(call, "%s does not take io.Writer but has first arg %s", fn.FullName(), analysisutil.Format(pass.Fset, call.Args[0])) |
| 1070 | } |
| 1071 | } |
| 1072 | } |
| 1073 | } |
| 1074 | |
| 1075 | arg := args[0] |
| 1076 | if s, ok := stringConstantExpr(pass, arg); ok { |
| 1077 | // Ignore trailing % character |
| 1078 | // The % in "abc 0.0%" couldn't be a formatting directive. |
| 1079 | s = strings.TrimSuffix(s, "%") |
| 1080 | if strings.Contains(s, "%") { |
| 1081 | m := printFormatRE.FindStringSubmatch(s) |
| 1082 | if m != nil { |
| 1083 | pass.ReportRangef(call, "%s call has possible formatting directive %s", fn.FullName(), m[0]) |
| 1084 | } |
| 1085 | } |
| 1086 | } |
| 1087 | if strings.HasSuffix(fn.Name(), "ln") { |
| 1088 | // The last item, if a string, should not have a newline. |
| 1089 | arg = args[len(args)-1] |
| 1090 | if s, ok := stringConstantExpr(pass, arg); ok { |
| 1091 | if strings.HasSuffix(s, "\n") { |
| 1092 | pass.ReportRangef(call, "%s arg list ends with redundant newline", fn.FullName()) |
| 1093 | } |
| 1094 | } |
| 1095 | } |
| 1096 | for _, arg := range args { |
| 1097 | if isFunctionValue(pass, arg) { |
| 1098 | pass.ReportRangef(call, "%s arg %s is a func value, not called", fn.FullName(), analysisutil.Format(pass.Fset, arg)) |
| 1099 | } |
| 1100 | if methodName, ok := recursiveStringer(pass, arg); ok { |
| 1101 | pass.ReportRangef(call, "%s arg %s causes recursive call to %s method", fn.FullName(), analysisutil.Format(pass.Fset, arg), methodName) |
| 1102 | } |
| 1103 | } |
| 1104 | } |
| 1105 | |
| 1106 | // count(n, what) returns "1 what" or "N whats" |
| 1107 | // (assuming the plural of what is whats). |
| 1108 | func count(n int, what string) string { |
| 1109 | if n == 1 { |
| 1110 | return "1 " + what |
| 1111 | } |
| 1112 | return fmt.Sprintf("%d %ss", n, what) |
| 1113 | } |
| 1114 | |
| 1115 | // stringSet is a set-of-nonempty-strings-valued flag. |
| 1116 | // Note: elements without a '.' get lower-cased. |
| 1117 | type stringSet map[string]bool |
| 1118 | |
| 1119 | func (ss stringSet) String() string { |
| 1120 | var list []string |
| 1121 | for name := range ss { |
| 1122 | list = append(list, name) |
| 1123 | } |
| 1124 | sort.Strings(list) |
| 1125 | return strings.Join(list, ",") |
| 1126 | } |
| 1127 | |
| 1128 | func (ss stringSet) Set(flag string) error { |
| 1129 | for _, name := range strings.Split(flag, ",") { |
| 1130 | if len(name) == 0 { |
| 1131 | return fmt.Errorf("empty string") |
| 1132 | } |
| 1133 | if !strings.Contains(name, ".") { |
| 1134 | name = strings.ToLower(name) |
| 1135 | } |
| 1136 | ss[name] = true |
| 1137 | } |
| 1138 | return nil |
| 1139 | } |
| 1140 |
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