gopkg.in/alecthomas/gometalinter.v3@v3.0.0/_linters/src/golang.org/x/tools/go/packages/golist.go (about) 1 // Copyright 2018 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 packages 6 7 import ( 8 "bytes" 9 "encoding/json" 10 "fmt" 11 "go/types" 12 "io/ioutil" 13 "log" 14 "os" 15 "os/exec" 16 "path/filepath" 17 "reflect" 18 "regexp" 19 "strconv" 20 "strings" 21 "sync" 22 "time" 23 24 "golang.org/x/tools/go/internal/packagesdriver" 25 "golang.org/x/tools/internal/gopathwalk" 26 "golang.org/x/tools/internal/semver" 27 ) 28 29 // debug controls verbose logging. 30 var debug, _ = strconv.ParseBool(os.Getenv("GOPACKAGESDEBUG")) 31 32 // A goTooOldError reports that the go command 33 // found by exec.LookPath is too old to use the new go list behavior. 34 type goTooOldError struct { 35 error 36 } 37 38 // responseDeduper wraps a driverResponse, deduplicating its contents. 39 type responseDeduper struct { 40 seenRoots map[string]bool 41 seenPackages map[string]*Package 42 dr *driverResponse 43 } 44 45 // init fills in r with a driverResponse. 46 func (r *responseDeduper) init(dr *driverResponse) { 47 r.dr = dr 48 r.seenRoots = map[string]bool{} 49 r.seenPackages = map[string]*Package{} 50 for _, pkg := range dr.Packages { 51 r.seenPackages[pkg.ID] = pkg 52 } 53 for _, root := range dr.Roots { 54 r.seenRoots[root] = true 55 } 56 } 57 58 func (r *responseDeduper) addPackage(p *Package) { 59 if r.seenPackages[p.ID] != nil { 60 return 61 } 62 r.seenPackages[p.ID] = p 63 r.dr.Packages = append(r.dr.Packages, p) 64 } 65 66 func (r *responseDeduper) addRoot(id string) { 67 if r.seenRoots[id] { 68 return 69 } 70 r.seenRoots[id] = true 71 r.dr.Roots = append(r.dr.Roots, id) 72 } 73 74 // goListDriver uses the go list command to interpret the patterns and produce 75 // the build system package structure. 76 // See driver for more details. 77 func goListDriver(cfg *Config, patterns ...string) (*driverResponse, error) { 78 var sizes types.Sizes 79 var sizeserr error 80 var sizeswg sync.WaitGroup 81 if cfg.Mode >= LoadTypes { 82 sizeswg.Add(1) 83 go func() { 84 sizes, sizeserr = getSizes(cfg) 85 sizeswg.Done() 86 }() 87 } 88 89 // Determine files requested in contains patterns 90 var containFiles []string 91 var packagesNamed []string 92 restPatterns := make([]string, 0, len(patterns)) 93 // Extract file= and other [querytype]= patterns. Report an error if querytype 94 // doesn't exist. 95 extractQueries: 96 for _, pattern := range patterns { 97 eqidx := strings.Index(pattern, "=") 98 if eqidx < 0 { 99 restPatterns = append(restPatterns, pattern) 100 } else { 101 query, value := pattern[:eqidx], pattern[eqidx+len("="):] 102 switch query { 103 case "file": 104 containFiles = append(containFiles, value) 105 case "pattern": 106 restPatterns = append(restPatterns, value) 107 case "name": 108 packagesNamed = append(packagesNamed, value) 109 case "": // not a reserved query 110 restPatterns = append(restPatterns, pattern) 111 default: 112 for _, rune := range query { 113 if rune < 'a' || rune > 'z' { // not a reserved query 114 restPatterns = append(restPatterns, pattern) 115 continue extractQueries 116 } 117 } 118 // Reject all other patterns containing "=" 119 return nil, fmt.Errorf("invalid query type %q in query pattern %q", query, pattern) 120 } 121 } 122 } 123 124 // TODO(matloob): Remove the definition of listfunc and just use golistPackages once go1.12 is released. 125 var listfunc driver 126 var isFallback bool 127 listfunc = func(cfg *Config, words ...string) (*driverResponse, error) { 128 response, err := golistDriverCurrent(cfg, words...) 129 if _, ok := err.(goTooOldError); ok { 130 isFallback = true 131 listfunc = golistDriverFallback 132 return listfunc(cfg, words...) 133 } 134 listfunc = golistDriverCurrent 135 return response, err 136 } 137 138 response := &responseDeduper{} 139 var err error 140 141 // See if we have any patterns to pass through to go list. Zero initial 142 // patterns also requires a go list call, since it's the equivalent of 143 // ".". 144 if len(restPatterns) > 0 || len(patterns) == 0 { 145 dr, err := listfunc(cfg, restPatterns...) 146 if err != nil { 147 return nil, err 148 } 149 response.init(dr) 150 } else { 151 response.init(&driverResponse{}) 152 } 153 154 sizeswg.Wait() 155 if sizeserr != nil { 156 return nil, sizeserr 157 } 158 // types.SizesFor always returns nil or a *types.StdSizes 159 response.dr.Sizes, _ = sizes.(*types.StdSizes) 160 161 var containsCandidates []string 162 163 if len(containFiles) != 0 { 164 if err := runContainsQueries(cfg, listfunc, isFallback, response, containFiles); err != nil { 165 return nil, err 166 } 167 } 168 169 if len(packagesNamed) != 0 { 170 if err := runNamedQueries(cfg, listfunc, response, packagesNamed); err != nil { 171 return nil, err 172 } 173 } 174 175 modifiedPkgs, needPkgs, err := processGolistOverlay(cfg, response.dr) 176 if err != nil { 177 return nil, err 178 } 179 if len(containFiles) > 0 { 180 containsCandidates = append(containsCandidates, modifiedPkgs...) 181 containsCandidates = append(containsCandidates, needPkgs...) 182 } 183 184 if len(needPkgs) > 0 { 185 addNeededOverlayPackages(cfg, listfunc, response, needPkgs) 186 if err != nil { 187 return nil, err 188 } 189 } 190 // Check candidate packages for containFiles. 191 if len(containFiles) > 0 { 192 for _, id := range containsCandidates { 193 pkg := response.seenPackages[id] 194 for _, f := range containFiles { 195 for _, g := range pkg.GoFiles { 196 if sameFile(f, g) { 197 response.addRoot(id) 198 } 199 } 200 } 201 } 202 } 203 204 return response.dr, nil 205 } 206 207 func addNeededOverlayPackages(cfg *Config, driver driver, response *responseDeduper, pkgs []string) error { 208 dr, err := driver(cfg, pkgs...) 209 if err != nil { 210 return err 211 } 212 for _, pkg := range dr.Packages { 213 response.addPackage(pkg) 214 } 215 return nil 216 } 217 218 func runContainsQueries(cfg *Config, driver driver, isFallback bool, response *responseDeduper, queries []string) error { 219 for _, query := range queries { 220 // TODO(matloob): Do only one query per directory. 221 fdir := filepath.Dir(query) 222 // Pass absolute path of directory to go list so that it knows to treat it as a directory, 223 // not a package path. 224 pattern, err := filepath.Abs(fdir) 225 if err != nil { 226 return fmt.Errorf("could not determine absolute path of file= query path %q: %v", query, err) 227 } 228 if isFallback { 229 pattern = "." 230 cfg.Dir = fdir 231 } 232 233 dirResponse, err := driver(cfg, pattern) 234 if err != nil { 235 return err 236 } 237 isRoot := make(map[string]bool, len(dirResponse.Roots)) 238 for _, root := range dirResponse.Roots { 239 isRoot[root] = true 240 } 241 for _, pkg := range dirResponse.Packages { 242 // Add any new packages to the main set 243 // We don't bother to filter packages that will be dropped by the changes of roots, 244 // that will happen anyway during graph construction outside this function. 245 // Over-reporting packages is not a problem. 246 response.addPackage(pkg) 247 // if the package was not a root one, it cannot have the file 248 if !isRoot[pkg.ID] { 249 continue 250 } 251 for _, pkgFile := range pkg.GoFiles { 252 if filepath.Base(query) == filepath.Base(pkgFile) { 253 response.addRoot(pkg.ID) 254 break 255 } 256 } 257 } 258 } 259 return nil 260 } 261 262 // modCacheRegexp splits a path in a module cache into module, module version, and package. 263 var modCacheRegexp = regexp.MustCompile(`(.*)@([^/\\]*)(.*)`) 264 265 func runNamedQueries(cfg *Config, driver driver, response *responseDeduper, queries []string) error { 266 // calling `go env` isn't free; bail out if there's nothing to do. 267 if len(queries) == 0 { 268 return nil 269 } 270 // Determine which directories are relevant to scan. 271 roots, modRoot, err := roots(cfg) 272 if err != nil { 273 return err 274 } 275 276 // Scan the selected directories. Simple matches, from GOPATH/GOROOT 277 // or the local module, can simply be "go list"ed. Matches from the 278 // module cache need special treatment. 279 var matchesMu sync.Mutex 280 var simpleMatches, modCacheMatches []string 281 add := func(root gopathwalk.Root, dir string) { 282 // Walk calls this concurrently; protect the result slices. 283 matchesMu.Lock() 284 defer matchesMu.Unlock() 285 286 path := dir[len(root.Path)+1:] 287 if pathMatchesQueries(path, queries) { 288 switch root.Type { 289 case gopathwalk.RootModuleCache: 290 modCacheMatches = append(modCacheMatches, path) 291 case gopathwalk.RootCurrentModule: 292 // We'd need to read go.mod to find the full 293 // import path. Relative's easier. 294 rel, err := filepath.Rel(cfg.Dir, dir) 295 if err != nil { 296 // This ought to be impossible, since 297 // we found dir in the current module. 298 panic(err) 299 } 300 simpleMatches = append(simpleMatches, "./"+rel) 301 case gopathwalk.RootGOPATH, gopathwalk.RootGOROOT: 302 simpleMatches = append(simpleMatches, path) 303 } 304 } 305 } 306 307 startWalk := time.Now() 308 gopathwalk.Walk(roots, add, gopathwalk.Options{ModulesEnabled: modRoot != "", Debug: debug}) 309 if debug { 310 log.Printf("%v for walk", time.Since(startWalk)) 311 } 312 313 // Weird special case: the top-level package in a module will be in 314 // whatever directory the user checked the repository out into. It's 315 // more reasonable for that to not match the package name. So, if there 316 // are any Go files in the mod root, query it just to be safe. 317 if modRoot != "" { 318 rel, err := filepath.Rel(cfg.Dir, modRoot) 319 if err != nil { 320 panic(err) // See above. 321 } 322 323 files, err := ioutil.ReadDir(modRoot) 324 for _, f := range files { 325 if strings.HasSuffix(f.Name(), ".go") { 326 simpleMatches = append(simpleMatches, rel) 327 break 328 } 329 } 330 } 331 332 addResponse := func(r *driverResponse) { 333 for _, pkg := range r.Packages { 334 response.addPackage(pkg) 335 for _, name := range queries { 336 if pkg.Name == name { 337 response.addRoot(pkg.ID) 338 break 339 } 340 } 341 } 342 } 343 344 if len(simpleMatches) != 0 { 345 resp, err := driver(cfg, simpleMatches...) 346 if err != nil { 347 return err 348 } 349 addResponse(resp) 350 } 351 352 // Module cache matches are tricky. We want to avoid downloading new 353 // versions of things, so we need to use the ones present in the cache. 354 // go list doesn't accept version specifiers, so we have to write out a 355 // temporary module, and do the list in that module. 356 if len(modCacheMatches) != 0 { 357 // Collect all the matches, deduplicating by major version 358 // and preferring the newest. 359 type modInfo struct { 360 mod string 361 major string 362 } 363 mods := make(map[modInfo]string) 364 var imports []string 365 for _, modPath := range modCacheMatches { 366 matches := modCacheRegexp.FindStringSubmatch(modPath) 367 mod, ver := filepath.ToSlash(matches[1]), matches[2] 368 importPath := filepath.ToSlash(filepath.Join(matches[1], matches[3])) 369 370 major := semver.Major(ver) 371 if prevVer, ok := mods[modInfo{mod, major}]; !ok || semver.Compare(ver, prevVer) > 0 { 372 mods[modInfo{mod, major}] = ver 373 } 374 375 imports = append(imports, importPath) 376 } 377 378 // Build the temporary module. 379 var gomod bytes.Buffer 380 gomod.WriteString("module modquery\nrequire (\n") 381 for mod, version := range mods { 382 gomod.WriteString("\t" + mod.mod + " " + version + "\n") 383 } 384 gomod.WriteString(")\n") 385 386 tmpCfg := *cfg 387 388 // We're only trying to look at stuff in the module cache, so 389 // disable the network. This should speed things up, and has 390 // prevented errors in at least one case, #28518. 391 tmpCfg.Env = append(append([]string{"GOPROXY=off"}, cfg.Env...)) 392 393 var err error 394 tmpCfg.Dir, err = ioutil.TempDir("", "gopackages-modquery") 395 if err != nil { 396 return err 397 } 398 defer os.RemoveAll(tmpCfg.Dir) 399 400 if err := ioutil.WriteFile(filepath.Join(tmpCfg.Dir, "go.mod"), gomod.Bytes(), 0777); err != nil { 401 return fmt.Errorf("writing go.mod for module cache query: %v", err) 402 } 403 404 // Run the query, using the import paths calculated from the matches above. 405 resp, err := driver(&tmpCfg, imports...) 406 if err != nil { 407 return fmt.Errorf("querying module cache matches: %v", err) 408 } 409 addResponse(resp) 410 } 411 412 return nil 413 } 414 415 func getSizes(cfg *Config) (types.Sizes, error) { 416 return packagesdriver.GetSizesGolist(cfg.Context, cfg.BuildFlags, cfg.Env, cfg.Dir, usesExportData(cfg)) 417 } 418 419 // roots selects the appropriate paths to walk based on the passed-in configuration, 420 // particularly the environment and the presence of a go.mod in cfg.Dir's parents. 421 func roots(cfg *Config) ([]gopathwalk.Root, string, error) { 422 stdout, err := invokeGo(cfg, "env", "GOROOT", "GOPATH", "GOMOD") 423 if err != nil { 424 return nil, "", err 425 } 426 427 fields := strings.Split(stdout.String(), "\n") 428 if len(fields) != 4 || len(fields[3]) != 0 { 429 return nil, "", fmt.Errorf("go env returned unexpected output: %q", stdout.String()) 430 } 431 goroot, gopath, gomod := fields[0], filepath.SplitList(fields[1]), fields[2] 432 var modDir string 433 if gomod != "" { 434 modDir = filepath.Dir(gomod) 435 } 436 437 var roots []gopathwalk.Root 438 // Always add GOROOT. 439 roots = append(roots, gopathwalk.Root{filepath.Join(goroot, "/src"), gopathwalk.RootGOROOT}) 440 // If modules are enabled, scan the module dir. 441 if modDir != "" { 442 roots = append(roots, gopathwalk.Root{modDir, gopathwalk.RootCurrentModule}) 443 } 444 // Add either GOPATH/src or GOPATH/pkg/mod, depending on module mode. 445 for _, p := range gopath { 446 if modDir != "" { 447 roots = append(roots, gopathwalk.Root{filepath.Join(p, "/pkg/mod"), gopathwalk.RootModuleCache}) 448 } else { 449 roots = append(roots, gopathwalk.Root{filepath.Join(p, "/src"), gopathwalk.RootGOPATH}) 450 } 451 } 452 453 return roots, modDir, nil 454 } 455 456 // These functions were copied from goimports. See further documentation there. 457 458 // pathMatchesQueries is adapted from pkgIsCandidate. 459 // TODO: is it reasonable to do Contains here, rather than an exact match on a path component? 460 func pathMatchesQueries(path string, queries []string) bool { 461 lastTwo := lastTwoComponents(path) 462 for _, query := range queries { 463 if strings.Contains(lastTwo, query) { 464 return true 465 } 466 if hasHyphenOrUpperASCII(lastTwo) && !hasHyphenOrUpperASCII(query) { 467 lastTwo = lowerASCIIAndRemoveHyphen(lastTwo) 468 if strings.Contains(lastTwo, query) { 469 return true 470 } 471 } 472 } 473 return false 474 } 475 476 // lastTwoComponents returns at most the last two path components 477 // of v, using either / or \ as the path separator. 478 func lastTwoComponents(v string) string { 479 nslash := 0 480 for i := len(v) - 1; i >= 0; i-- { 481 if v[i] == '/' || v[i] == '\\' { 482 nslash++ 483 if nslash == 2 { 484 return v[i:] 485 } 486 } 487 } 488 return v 489 } 490 491 func hasHyphenOrUpperASCII(s string) bool { 492 for i := 0; i < len(s); i++ { 493 b := s[i] 494 if b == '-' || ('A' <= b && b <= 'Z') { 495 return true 496 } 497 } 498 return false 499 } 500 501 func lowerASCIIAndRemoveHyphen(s string) (ret string) { 502 buf := make([]byte, 0, len(s)) 503 for i := 0; i < len(s); i++ { 504 b := s[i] 505 switch { 506 case b == '-': 507 continue 508 case 'A' <= b && b <= 'Z': 509 buf = append(buf, b+('a'-'A')) 510 default: 511 buf = append(buf, b) 512 } 513 } 514 return string(buf) 515 } 516 517 // Fields must match go list; 518 // see $GOROOT/src/cmd/go/internal/load/pkg.go. 519 type jsonPackage struct { 520 ImportPath string 521 Dir string 522 Name string 523 Export string 524 GoFiles []string 525 CompiledGoFiles []string 526 CFiles []string 527 CgoFiles []string 528 CXXFiles []string 529 MFiles []string 530 HFiles []string 531 FFiles []string 532 SFiles []string 533 SwigFiles []string 534 SwigCXXFiles []string 535 SysoFiles []string 536 Imports []string 537 ImportMap map[string]string 538 Deps []string 539 TestGoFiles []string 540 TestImports []string 541 XTestGoFiles []string 542 XTestImports []string 543 ForTest string // q in a "p [q.test]" package, else "" 544 DepOnly bool 545 546 Error *jsonPackageError 547 } 548 549 type jsonPackageError struct { 550 ImportStack []string 551 Pos string 552 Err string 553 } 554 555 func otherFiles(p *jsonPackage) [][]string { 556 return [][]string{p.CFiles, p.CXXFiles, p.MFiles, p.HFiles, p.FFiles, p.SFiles, p.SwigFiles, p.SwigCXXFiles, p.SysoFiles} 557 } 558 559 // golistDriverCurrent uses the "go list" command to expand the 560 // pattern words and return metadata for the specified packages. 561 // dir may be "" and env may be nil, as per os/exec.Command. 562 func golistDriverCurrent(cfg *Config, words ...string) (*driverResponse, error) { 563 // go list uses the following identifiers in ImportPath and Imports: 564 // 565 // "p" -- importable package or main (command) 566 // "q.test" -- q's test executable 567 // "p [q.test]" -- variant of p as built for q's test executable 568 // "q_test [q.test]" -- q's external test package 569 // 570 // The packages p that are built differently for a test q.test 571 // are q itself, plus any helpers used by the external test q_test, 572 // typically including "testing" and all its dependencies. 573 574 // Run "go list" for complete 575 // information on the specified packages. 576 buf, err := invokeGo(cfg, golistargs(cfg, words)...) 577 if err != nil { 578 return nil, err 579 } 580 seen := make(map[string]*jsonPackage) 581 // Decode the JSON and convert it to Package form. 582 var response driverResponse 583 for dec := json.NewDecoder(buf); dec.More(); { 584 p := new(jsonPackage) 585 if err := dec.Decode(p); err != nil { 586 return nil, fmt.Errorf("JSON decoding failed: %v", err) 587 } 588 589 if p.ImportPath == "" { 590 // The documentation for go list says that “[e]rroneous packages will have 591 // a non-empty ImportPath”. If for some reason it comes back empty, we 592 // prefer to error out rather than silently discarding data or handing 593 // back a package without any way to refer to it. 594 if p.Error != nil { 595 return nil, Error{ 596 Pos: p.Error.Pos, 597 Msg: p.Error.Err, 598 } 599 } 600 return nil, fmt.Errorf("package missing import path: %+v", p) 601 } 602 603 if old, found := seen[p.ImportPath]; found { 604 if !reflect.DeepEqual(p, old) { 605 return nil, fmt.Errorf("go list repeated package %v with different values", p.ImportPath) 606 } 607 // skip the duplicate 608 continue 609 } 610 seen[p.ImportPath] = p 611 612 pkg := &Package{ 613 Name: p.Name, 614 ID: p.ImportPath, 615 GoFiles: absJoin(p.Dir, p.GoFiles, p.CgoFiles), 616 CompiledGoFiles: absJoin(p.Dir, p.CompiledGoFiles), 617 OtherFiles: absJoin(p.Dir, otherFiles(p)...), 618 } 619 620 // Workaround for https://golang.org/issue/28749. 621 // TODO(adonovan): delete before go1.12 release. 622 out := pkg.CompiledGoFiles[:0] 623 for _, f := range pkg.CompiledGoFiles { 624 if strings.HasSuffix(f, ".s") { 625 continue 626 } 627 out = append(out, f) 628 } 629 pkg.CompiledGoFiles = out 630 631 // Extract the PkgPath from the package's ID. 632 if i := strings.IndexByte(pkg.ID, ' '); i >= 0 { 633 pkg.PkgPath = pkg.ID[:i] 634 } else { 635 pkg.PkgPath = pkg.ID 636 } 637 638 if pkg.PkgPath == "unsafe" { 639 pkg.GoFiles = nil // ignore fake unsafe.go file 640 } 641 642 // Assume go list emits only absolute paths for Dir. 643 if p.Dir != "" && !filepath.IsAbs(p.Dir) { 644 log.Fatalf("internal error: go list returned non-absolute Package.Dir: %s", p.Dir) 645 } 646 647 if p.Export != "" && !filepath.IsAbs(p.Export) { 648 pkg.ExportFile = filepath.Join(p.Dir, p.Export) 649 } else { 650 pkg.ExportFile = p.Export 651 } 652 653 // imports 654 // 655 // Imports contains the IDs of all imported packages. 656 // ImportsMap records (path, ID) only where they differ. 657 ids := make(map[string]bool) 658 for _, id := range p.Imports { 659 ids[id] = true 660 } 661 pkg.Imports = make(map[string]*Package) 662 for path, id := range p.ImportMap { 663 pkg.Imports[path] = &Package{ID: id} // non-identity import 664 delete(ids, id) 665 } 666 for id := range ids { 667 if id == "C" { 668 continue 669 } 670 671 pkg.Imports[id] = &Package{ID: id} // identity import 672 } 673 if !p.DepOnly { 674 response.Roots = append(response.Roots, pkg.ID) 675 } 676 677 // Work around for pre-go.1.11 versions of go list. 678 // TODO(matloob): they should be handled by the fallback. 679 // Can we delete this? 680 if len(pkg.CompiledGoFiles) == 0 { 681 pkg.CompiledGoFiles = pkg.GoFiles 682 } 683 684 if p.Error != nil { 685 pkg.Errors = append(pkg.Errors, Error{ 686 Pos: p.Error.Pos, 687 Msg: p.Error.Err, 688 }) 689 } 690 691 response.Packages = append(response.Packages, pkg) 692 } 693 694 return &response, nil 695 } 696 697 // absJoin absolutizes and flattens the lists of files. 698 func absJoin(dir string, fileses ...[]string) (res []string) { 699 for _, files := range fileses { 700 for _, file := range files { 701 if !filepath.IsAbs(file) { 702 file = filepath.Join(dir, file) 703 } 704 res = append(res, file) 705 } 706 } 707 return res 708 } 709 710 func golistargs(cfg *Config, words []string) []string { 711 fullargs := []string{ 712 "list", "-e", "-json", "-compiled", 713 fmt.Sprintf("-test=%t", cfg.Tests), 714 fmt.Sprintf("-export=%t", usesExportData(cfg)), 715 fmt.Sprintf("-deps=%t", cfg.Mode >= LoadImports), 716 // go list doesn't let you pass -test and -find together, 717 // probably because you'd just get the TestMain. 718 fmt.Sprintf("-find=%t", cfg.Mode < LoadImports && !cfg.Tests), 719 } 720 fullargs = append(fullargs, cfg.BuildFlags...) 721 fullargs = append(fullargs, "--") 722 fullargs = append(fullargs, words...) 723 return fullargs 724 } 725 726 // invokeGo returns the stdout of a go command invocation. 727 func invokeGo(cfg *Config, args ...string) (*bytes.Buffer, error) { 728 if debug { 729 defer func(start time.Time) { log.Printf("%s for %v", time.Since(start), cmdDebugStr(cfg, args...)) }(time.Now()) 730 } 731 stdout := new(bytes.Buffer) 732 stderr := new(bytes.Buffer) 733 cmd := exec.CommandContext(cfg.Context, "go", args...) 734 // On darwin the cwd gets resolved to the real path, which breaks anything that 735 // expects the working directory to keep the original path, including the 736 // go command when dealing with modules. 737 // The Go stdlib has a special feature where if the cwd and the PWD are the 738 // same node then it trusts the PWD, so by setting it in the env for the child 739 // process we fix up all the paths returned by the go command. 740 cmd.Env = append(append([]string{}, cfg.Env...), "PWD="+cfg.Dir) 741 cmd.Dir = cfg.Dir 742 cmd.Stdout = stdout 743 cmd.Stderr = stderr 744 if err := cmd.Run(); err != nil { 745 exitErr, ok := err.(*exec.ExitError) 746 if !ok { 747 // Catastrophic error: 748 // - executable not found 749 // - context cancellation 750 return nil, fmt.Errorf("couldn't exec 'go %v': %s %T", args, err, err) 751 } 752 753 // Old go version? 754 if strings.Contains(stderr.String(), "flag provided but not defined") { 755 return nil, goTooOldError{fmt.Errorf("unsupported version of go: %s: %s", exitErr, stderr)} 756 } 757 758 // Export mode entails a build. 759 // If that build fails, errors appear on stderr 760 // (despite the -e flag) and the Export field is blank. 761 // Do not fail in that case. 762 // The same is true if an ad-hoc package given to go list doesn't exist. 763 // TODO(matloob): Remove these once we can depend on go list to exit with a zero status with -e even when 764 // packages don't exist or a build fails. 765 if !usesExportData(cfg) && !containsGoFile(args) { 766 return nil, fmt.Errorf("go %v: %s: %s", args, exitErr, stderr) 767 } 768 } 769 770 // As of writing, go list -export prints some non-fatal compilation 771 // errors to stderr, even with -e set. We would prefer that it put 772 // them in the Package.Error JSON (see https://golang.org/issue/26319). 773 // In the meantime, there's nowhere good to put them, but they can 774 // be useful for debugging. Print them if $GOPACKAGESPRINTGOLISTERRORS 775 // is set. 776 if len(stderr.Bytes()) != 0 && os.Getenv("GOPACKAGESPRINTGOLISTERRORS") != "" { 777 fmt.Fprintf(os.Stderr, "%s stderr: <<%s>>\n", cmdDebugStr(cfg, args...), stderr) 778 } 779 780 // debugging 781 if false { 782 fmt.Fprintf(os.Stderr, "%s stdout: <<%s>>\n", cmdDebugStr(cfg, args...), stdout) 783 } 784 785 return stdout, nil 786 } 787 788 func containsGoFile(s []string) bool { 789 for _, f := range s { 790 if strings.HasSuffix(f, ".go") { 791 return true 792 } 793 } 794 return false 795 } 796 797 func cmdDebugStr(cfg *Config, args ...string) string { 798 env := make(map[string]string) 799 for _, kv := range cfg.Env { 800 split := strings.Split(kv, "=") 801 k, v := split[0], split[1] 802 env[k] = v 803 } 804 805 return fmt.Sprintf("GOROOT=%v GOPATH=%v GO111MODULE=%v PWD=%v go %v", env["GOROOT"], env["GOPATH"], env["GO111MODULE"], env["PWD"], args) 806 }