diff options
Diffstat (limited to 'src/cmd/go/internal/modget')
| -rw-r--r-- | src/cmd/go/internal/modget/get.go | 1687 | ||||
| -rw-r--r-- | src/cmd/go/internal/modget/query.go | 357 |
2 files changed, 2044 insertions, 0 deletions
diff --git a/src/cmd/go/internal/modget/get.go b/src/cmd/go/internal/modget/get.go new file mode 100644 index 0000000..5a98408 --- /dev/null +++ b/src/cmd/go/internal/modget/get.go @@ -0,0 +1,1687 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Package modget implements the module-aware ``go get'' command. +package modget + +// The arguments to 'go get' are patterns with optional version queries, with +// the version queries defaulting to "upgrade". +// +// The patterns are normally interpreted as package patterns. However, if a +// pattern cannot match a package, it is instead interpreted as a *module* +// pattern. For version queries such as "upgrade" and "patch" that depend on the +// selected version of a module (or of the module containing a package), +// whether a pattern denotes a package or module may change as updates are +// applied (see the example in mod_get_patchmod.txt). +// +// There are a few other ambiguous cases to resolve, too. A package can exist in +// two different modules at the same version: for example, the package +// example.com/foo might be found in module example.com and also in module +// example.com/foo, and those modules may have independent v0.1.0 tags — so the +// input 'example.com/foo@v0.1.0' could syntactically refer to the variant of +// the package loaded from either module! (See mod_get_ambiguous_pkg.txt.) +// If the argument is ambiguous, the user can often disambiguate by specifying +// explicit versions for *all* of the potential module paths involved. + +import ( + "context" + "errors" + "fmt" + "os" + "path/filepath" + "reflect" + "runtime" + "sort" + "strings" + "sync" + + "cmd/go/internal/base" + "cmd/go/internal/cfg" + "cmd/go/internal/imports" + "cmd/go/internal/load" + "cmd/go/internal/modload" + "cmd/go/internal/par" + "cmd/go/internal/search" + "cmd/go/internal/work" + + "golang.org/x/mod/modfile" + "golang.org/x/mod/module" + "golang.org/x/mod/semver" +) + +var CmdGet = &base.Command{ + // Note: -d -u are listed explicitly because they are the most common get flags. + // Do not send CLs removing them because they're covered by [get flags]. + UsageLine: "go get [-d] [-t] [-u] [-v] [-insecure] [build flags] [packages]", + Short: "add dependencies to current module and install them", + Long: ` +Get resolves its command-line arguments to packages at specific module versions, +updates go.mod to require those versions, downloads source code into the +module cache, then builds and installs the named packages. + +To add a dependency for a package or upgrade it to its latest version: + + go get example.com/pkg + +To upgrade or downgrade a package to a specific version: + + go get example.com/pkg@v1.2.3 + +To remove a dependency on a module and downgrade modules that require it: + + go get example.com/mod@none + +See https://golang.org/ref/mod#go-get for details. + +The 'go install' command may be used to build and install packages. When a +version is specified, 'go install' runs in module-aware mode and ignores +the go.mod file in the current directory. For example: + + go install example.com/pkg@v1.2.3 + go install example.com/pkg@latest + +See 'go help install' or https://golang.org/ref/mod#go-install for details. + +In addition to build flags (listed in 'go help build') 'go get' accepts the +following flags. + +The -t flag instructs get to consider modules needed to build tests of +packages specified on the command line. + +The -u flag instructs get to update modules providing dependencies +of packages named on the command line to use newer minor or patch +releases when available. + +The -u=patch flag (not -u patch) also instructs get to update dependencies, +but changes the default to select patch releases. + +When the -t and -u flags are used together, get will update +test dependencies as well. + +The -insecure flag permits fetching from repositories and resolving +custom domains using insecure schemes such as HTTP, and also bypassess +module sum validation using the checksum database. Use with caution. +This flag is deprecated and will be removed in a future version of go. +To permit the use of insecure schemes, use the GOINSECURE environment +variable instead. To bypass module sum validation, use GOPRIVATE or +GONOSUMDB. See 'go help environment' for details. + +The -d flag instructs get not to build or install packages. get will only +update go.mod and download source code needed to build packages. + +Building and installing packages with get is deprecated. In a future release, +the -d flag will be enabled by default, and 'go get' will be only be used to +adjust dependencies of the current module. To install a package using +dependencies from the current module, use 'go install'. To install a package +ignoring the current module, use 'go install' with an @version suffix like +"@latest" after each argument. + +For more about modules, see https://golang.org/ref/mod. + +For more about specifying packages, see 'go help packages'. + +This text describes the behavior of get using modules to manage source +code and dependencies. If instead the go command is running in GOPATH +mode, the details of get's flags and effects change, as does 'go help get'. +See 'go help gopath-get'. + +See also: go build, go install, go clean, go mod. + `, +} + +// Note that this help text is a stopgap to make the module-aware get help text +// available even in non-module settings. It should be deleted when the old get +// is deleted. It should NOT be considered to set a precedent of having hierarchical +// help names with dashes. +var HelpModuleGet = &base.Command{ + UsageLine: "module-get", + Short: "module-aware go get", + Long: ` +The 'go get' command changes behavior depending on whether the +go command is running in module-aware mode or legacy GOPATH mode. +This help text, accessible as 'go help module-get' even in legacy GOPATH mode, +describes 'go get' as it operates in module-aware mode. + +Usage: ` + CmdGet.UsageLine + ` +` + CmdGet.Long, +} + +var HelpVCS = &base.Command{ + UsageLine: "vcs", + Short: "controlling version control with GOVCS", + Long: ` +The 'go get' command can run version control commands like git +to download imported code. This functionality is critical to the decentralized +Go package ecosystem, in which code can be imported from any server, +but it is also a potential security problem, if a malicious server finds a +way to cause the invoked version control command to run unintended code. + +To balance the functionality and security concerns, the 'go get' command +by default will only use git and hg to download code from public servers. +But it will use any known version control system (bzr, fossil, git, hg, svn) +to download code from private servers, defined as those hosting packages +matching the GOPRIVATE variable (see 'go help private'). The rationale behind +allowing only Git and Mercurial is that these two systems have had the most +attention to issues of being run as clients of untrusted servers. In contrast, +Bazaar, Fossil, and Subversion have primarily been used in trusted, +authenticated environments and are not as well scrutinized as attack surfaces. + +The version control command restrictions only apply when using direct version +control access to download code. When downloading modules from a proxy, +'go get' uses the proxy protocol instead, which is always permitted. +By default, the 'go get' command uses the Go module mirror (proxy.golang.org) +for public packages and only falls back to version control for private +packages or when the mirror refuses to serve a public package (typically for +legal reasons). Therefore, clients can still access public code served from +Bazaar, Fossil, or Subversion repositories by default, because those downloads +use the Go module mirror, which takes on the security risk of running the +version control commands using a custom sandbox. + +The GOVCS variable can be used to change the allowed version control systems +for specific packages (identified by a module or import path). +The GOVCS variable applies when building package in both module-aware mode +and GOPATH mode. When using modules, the patterns match against the module path. +When using GOPATH, the patterns match against the import path corresponding to +the root of the version control repository. + +The general form of the GOVCS setting is a comma-separated list of +pattern:vcslist rules. The pattern is a glob pattern that must match +one or more leading elements of the module or import path. The vcslist +is a pipe-separated list of allowed version control commands, or "all" +to allow use of any known command, or "off" to disallow all commands. +Note that if a module matches a pattern with vcslist "off", it may still be +downloaded if the origin server uses the "mod" scheme, which instructs the +go command to download the module using the GOPROXY protocol. +The earliest matching pattern in the list applies, even if later patterns +might also match. + +For example, consider: + + GOVCS=github.com:git,evil.com:off,*:git|hg + +With this setting, code with a module or import path beginning with +github.com/ can only use git; paths on evil.com cannot use any version +control command, and all other paths (* matches everything) can use +only git or hg. + +The special patterns "public" and "private" match public and private +module or import paths. A path is private if it matches the GOPRIVATE +variable; otherwise it is public. + +If no rules in the GOVCS variable match a particular module or import path, +the 'go get' command applies its default rule, which can now be summarized +in GOVCS notation as 'public:git|hg,private:all'. + +To allow unfettered use of any version control system for any package, use: + + GOVCS=*:all + +To disable all use of version control, use: + + GOVCS=*:off + +The 'go env -w' command (see 'go help env') can be used to set the GOVCS +variable for future go command invocations. +`, +} + +var ( + getD = CmdGet.Flag.Bool("d", false, "") + getF = CmdGet.Flag.Bool("f", false, "") + getFix = CmdGet.Flag.Bool("fix", false, "") + getM = CmdGet.Flag.Bool("m", false, "") + getT = CmdGet.Flag.Bool("t", false, "") + getU upgradeFlag + // -insecure is cfg.Insecure + // -v is cfg.BuildV +) + +// upgradeFlag is a custom flag.Value for -u. +type upgradeFlag struct { + rawVersion string + version string +} + +func (*upgradeFlag) IsBoolFlag() bool { return true } // allow -u + +func (v *upgradeFlag) Set(s string) error { + if s == "false" { + v.version = "" + v.rawVersion = "" + } else if s == "true" { + v.version = "upgrade" + v.rawVersion = "" + } else { + v.version = s + v.rawVersion = s + } + return nil +} + +func (v *upgradeFlag) String() string { return "" } + +func init() { + work.AddBuildFlags(CmdGet, work.OmitModFlag) + CmdGet.Run = runGet // break init loop + CmdGet.Flag.BoolVar(&cfg.Insecure, "insecure", cfg.Insecure, "") + CmdGet.Flag.Var(&getU, "u", "") +} + +func runGet(ctx context.Context, cmd *base.Command, args []string) { + switch getU.version { + case "", "upgrade", "patch": + // ok + default: + base.Fatalf("go get: unknown upgrade flag -u=%s", getU.rawVersion) + } + if *getF { + fmt.Fprintf(os.Stderr, "go get: -f flag is a no-op when using modules\n") + } + if *getFix { + fmt.Fprintf(os.Stderr, "go get: -fix flag is a no-op when using modules\n") + } + if *getM { + base.Fatalf("go get: -m flag is no longer supported; consider -d to skip building packages") + } + if cfg.Insecure { + fmt.Fprintf(os.Stderr, "go get: -insecure flag is deprecated; see 'go help get' for details\n") + } + load.ModResolveTests = *getT + + // Do not allow any updating of go.mod until we've applied + // all the requested changes and checked that the result matches + // what was requested. + modload.DisallowWriteGoMod() + + // Allow looking up modules for import paths when outside of a module. + // 'go get' is expected to do this, unlike other commands. + modload.AllowMissingModuleImports() + + modload.LoadModFile(ctx) // Initializes modload.Target. + + queries := parseArgs(ctx, args) + + r := newResolver(ctx, queries) + r.performLocalQueries(ctx) + r.performPathQueries(ctx) + + for { + r.performWildcardQueries(ctx) + r.performPatternAllQueries(ctx) + + if changed := r.resolveCandidates(ctx, queries, nil); changed { + // 'go get' arguments can be (and often are) package patterns rather than + // (just) modules. A package can be provided by any module with a prefix + // of its import path, and a wildcard can even match packages in modules + // with totally different paths. Because of these effects, and because any + // change to the selected version of a module can bring in entirely new + // module paths as dependencies, we need to reissue queries whenever we + // change the build list. + // + // The result of any version query for a given module — even "upgrade" or + // "patch" — is always relative to the build list at the start of + // the 'go get' command, not an intermediate state, and is therefore + // dederministic and therefore cachable, and the constraints on the + // selected version of each module can only narrow as we iterate. + // + // "all" is functionally very similar to a wildcard pattern. The set of + // packages imported by the main module does not change, and the query + // result for the module containing each such package also does not change + // (it is always relative to the initial build list, before applying + // queries). So the only way that the result of an "all" query can change + // is if some matching package moves from one module in the build list + // to another, which should not happen very often. + continue + } + + // When we load imports, we detect the following conditions: + // + // - missing transitive depencies that need to be resolved from outside the + // current build list (note that these may add new matches for existing + // pattern queries!) + // + // - transitive dependencies that didn't match any other query, + // but need to be upgraded due to the -u flag + // + // - ambiguous import errors. + // TODO(#27899): Try to resolve ambiguous import errors automatically. + upgrades := r.findAndUpgradeImports(ctx, queries) + if changed := r.resolveCandidates(ctx, nil, upgrades); changed { + continue + } + + r.findMissingWildcards(ctx) + if changed := r.resolveCandidates(ctx, r.wildcardQueries, nil); changed { + continue + } + + break + } + + r.checkWildcardVersions(ctx) + + var pkgPatterns []string + for _, q := range queries { + if q.matchesPackages { + pkgPatterns = append(pkgPatterns, q.pattern) + } + } + r.checkPackagesAndRetractions(ctx, pkgPatterns) + + // We've already downloaded modules (and identified direct and indirect + // dependencies) by loading packages in findAndUpgradeImports. + // So if -d is set, we're done after the module work. + // + // Otherwise, we need to build and install the packages matched by + // command line arguments. + // Note that 'go get -u' without arguments is equivalent to + // 'go get -u .', so we'll typically build the package in the current + // directory. + if !*getD && len(pkgPatterns) > 0 { + work.BuildInit() + pkgs := load.PackagesAndErrors(ctx, pkgPatterns) + load.CheckPackageErrors(pkgs) + work.InstallPackages(ctx, pkgPatterns, pkgs) + // TODO(#40276): After Go 1.16, print a deprecation notice when building and + // installing main packages. 'go install pkg' or 'go install pkg@version' + // should be used instead. Give the specific argument to use if possible. + } + + if !modload.HasModRoot() { + return + } + + // Everything succeeded. Update go.mod. + oldReqs := reqsFromGoMod(modload.ModFile()) + + modload.AllowWriteGoMod() + modload.WriteGoMod() + modload.DisallowWriteGoMod() + + newReqs := reqsFromGoMod(modload.ModFile()) + r.reportChanges(oldReqs, newReqs) +} + +// parseArgs parses command-line arguments and reports errors. +// +// The command-line arguments are of the form path@version or simply path, with +// implicit @upgrade. path@none is "downgrade away". +func parseArgs(ctx context.Context, rawArgs []string) []*query { + defer base.ExitIfErrors() + + var queries []*query + for _, arg := range search.CleanPatterns(rawArgs) { + q, err := newQuery(arg) + if err != nil { + base.Errorf("go get: %v", err) + continue + } + + // If there were no arguments, CleanPatterns returns ".". Set the raw + // string back to "" for better errors. + if len(rawArgs) == 0 { + q.raw = "" + } + + // Guard against 'go get x.go', a common mistake. + // Note that package and module paths may end with '.go', so only print an error + // if the argument has no version and either has no slash or refers to an existing file. + if strings.HasSuffix(q.raw, ".go") && q.rawVersion == "" { + if !strings.Contains(q.raw, "/") { + base.Errorf("go get %s: arguments must be package or module paths", q.raw) + continue + } + if fi, err := os.Stat(q.raw); err == nil && !fi.IsDir() { + base.Errorf("go get: %s exists as a file, but 'go get' requires package arguments", q.raw) + continue + } + } + + queries = append(queries, q) + } + + return queries +} + +type resolver struct { + localQueries []*query // queries for absolute or relative paths + pathQueries []*query // package path literal queries in original order + wildcardQueries []*query // path wildcard queries in original order + patternAllQueries []*query // queries with the pattern "all" + + // Indexed "none" queries. These are also included in the slices above; + // they are indexed here to speed up noneForPath. + nonesByPath map[string]*query // path-literal "@none" queries indexed by path + wildcardNones []*query // wildcard "@none" queries + + // resolvedVersion maps each module path to the version of that module that + // must be selected in the final build list, along with the first query + // that resolved the module to that version (the “reason”). + resolvedVersion map[string]versionReason + + buildList []module.Version + buildListResolvedVersions int // len(resolvedVersion) when buildList was computed + buildListVersion map[string]string // index of buildList (module path → version) + + initialVersion map[string]string // index of the initial build list at the start of 'go get' + + missing []pathSet // candidates for missing transitive dependencies + + work *par.Queue + + matchInModuleCache par.Cache +} + +type versionReason struct { + version string + reason *query +} + +func newResolver(ctx context.Context, queries []*query) *resolver { + buildList := modload.LoadAllModules(ctx) + initialVersion := make(map[string]string, len(buildList)) + for _, m := range buildList { + initialVersion[m.Path] = m.Version + } + + r := &resolver{ + work: par.NewQueue(runtime.GOMAXPROCS(0)), + resolvedVersion: map[string]versionReason{}, + buildList: buildList, + buildListVersion: initialVersion, + initialVersion: initialVersion, + nonesByPath: map[string]*query{}, + } + + for _, q := range queries { + if q.pattern == "all" { + r.patternAllQueries = append(r.patternAllQueries, q) + } else if q.patternIsLocal { + r.localQueries = append(r.localQueries, q) + } else if q.isWildcard() { + r.wildcardQueries = append(r.wildcardQueries, q) + } else { + r.pathQueries = append(r.pathQueries, q) + } + + if q.version == "none" { + // Index "none" queries to make noneForPath more efficient. + if q.isWildcard() { + r.wildcardNones = append(r.wildcardNones, q) + } else { + // All "<path>@none" queries for the same path are identical; we only + // need to index one copy. + r.nonesByPath[q.pattern] = q + } + } + } + + return r +} + +// initialSelected returns the version of the module with the given path that +// was selected at the start of this 'go get' invocation. +func (r *resolver) initialSelected(mPath string) (version string) { + v, ok := r.initialVersion[mPath] + if !ok { + return "none" + } + return v +} + +// selected returns the version of the module with the given path that is +// selected in the resolver's current build list. +func (r *resolver) selected(mPath string) (version string) { + v, ok := r.buildListVersion[mPath] + if !ok { + return "none" + } + return v +} + +// noneForPath returns a "none" query matching the given module path, +// or found == false if no such query exists. +func (r *resolver) noneForPath(mPath string) (nq *query, found bool) { + if nq = r.nonesByPath[mPath]; nq != nil { + return nq, true + } + for _, nq := range r.wildcardNones { + if nq.matchesPath(mPath) { + return nq, true + } + } + return nil, false +} + +// queryModule wraps modload.Query, substituting r.checkAllowedOr to decide +// allowed versions. +func (r *resolver) queryModule(ctx context.Context, mPath, query string, selected func(string) string) (module.Version, error) { + current := r.initialSelected(mPath) + rev, err := modload.Query(ctx, mPath, query, current, r.checkAllowedOr(query, selected)) + if err != nil { + return module.Version{}, err + } + return module.Version{Path: mPath, Version: rev.Version}, nil +} + +// queryPackage wraps modload.QueryPackage, substituting r.checkAllowedOr to +// decide allowed versions. +func (r *resolver) queryPackages(ctx context.Context, pattern, query string, selected func(string) string) (pkgMods []module.Version, err error) { + results, err := modload.QueryPackages(ctx, pattern, query, selected, r.checkAllowedOr(query, selected)) + if len(results) > 0 { + pkgMods = make([]module.Version, 0, len(results)) + for _, qr := range results { + pkgMods = append(pkgMods, qr.Mod) + } + } + return pkgMods, err +} + +// queryPattern wraps modload.QueryPattern, substituting r.checkAllowedOr to +// decide allowed versions. +func (r *resolver) queryPattern(ctx context.Context, pattern, query string, selected func(string) string) (pkgMods []module.Version, mod module.Version, err error) { + results, modOnly, err := modload.QueryPattern(ctx, pattern, query, selected, r.checkAllowedOr(query, selected)) + if len(results) > 0 { + pkgMods = make([]module.Version, 0, len(results)) + for _, qr := range results { + pkgMods = append(pkgMods, qr.Mod) + } + } + if modOnly != nil { + mod = modOnly.Mod + } + return pkgMods, mod, err +} + +// checkAllowedOr is like modload.CheckAllowed, but it always allows the requested +// and current versions (even if they are retracted or otherwise excluded). +func (r *resolver) checkAllowedOr(requested string, selected func(string) string) modload.AllowedFunc { + return func(ctx context.Context, m module.Version) error { + if m.Version == requested { + return modload.CheckExclusions(ctx, m) + } + if (requested == "upgrade" || requested == "patch") && m.Version == selected(m.Path) { + return nil + } + return modload.CheckAllowed(ctx, m) + } +} + +// matchInModule is a caching wrapper around modload.MatchInModule. +func (r *resolver) matchInModule(ctx context.Context, pattern string, m module.Version) (packages []string, err error) { + type key struct { + pattern string + m module.Version + } + type entry struct { + packages []string + err error + } + + e := r.matchInModuleCache.Do(key{pattern, m}, func() interface{} { + match := modload.MatchInModule(ctx, pattern, m, imports.AnyTags()) + if len(match.Errs) > 0 { + return entry{match.Pkgs, match.Errs[0]} + } + return entry{match.Pkgs, nil} + }).(entry) + + return e.packages, e.err +} + +// queryNone adds a candidate set to q for each module matching q.pattern. +// Each candidate set has only one possible module version: the matched +// module at version "none". +// +// We interpret arguments to 'go get' as packages first, and fall back to +// modules second. However, no module exists at version "none", and therefore no +// package exists at that version either: we know that the argument cannot match +// any packages, and thus it must match modules instead. +func (r *resolver) queryNone(ctx context.Context, q *query) { + if search.IsMetaPackage(q.pattern) { + panic(fmt.Sprintf("internal error: queryNone called with pattern %q", q.pattern)) + } + + if !q.isWildcard() { + q.pathOnce(q.pattern, func() pathSet { + if modload.HasModRoot() && q.pattern == modload.Target.Path { + // The user has explicitly requested to downgrade their own module to + // version "none". This is not an entirely unreasonable request: it + // could plausibly mean “downgrade away everything that depends on any + // explicit version of the main module”, or “downgrade away the + // package with the same path as the main module, found in a module + // with a prefix of the main module's path”. + // + // However, neither of those behaviors would be consistent with the + // plain meaning of the query. To try to reduce confusion, reject the + // query explicitly. + return errSet(&modload.QueryMatchesMainModuleError{Pattern: q.pattern, Query: q.version}) + } + + return pathSet{mod: module.Version{Path: q.pattern, Version: "none"}} + }) + } + + for _, curM := range r.buildList { + if !q.matchesPath(curM.Path) { + continue + } + q.pathOnce(curM.Path, func() pathSet { + if modload.HasModRoot() && curM == modload.Target { + return errSet(&modload.QueryMatchesMainModuleError{Pattern: q.pattern, Query: q.version}) + } + return pathSet{mod: module.Version{Path: curM.Path, Version: "none"}} + }) + } +} + +func (r *resolver) performLocalQueries(ctx context.Context) { + for _, q := range r.localQueries { + q.pathOnce(q.pattern, func() pathSet { + absDetail := "" + if !filepath.IsAbs(q.pattern) { + if absPath, err := filepath.Abs(q.pattern); err == nil { + absDetail = fmt.Sprintf(" (%s)", absPath) + } + } + + // Absolute paths like C:\foo and relative paths like ../foo... are + // restricted to matching packages in the main module. + pkgPattern := modload.DirImportPath(q.pattern) + if pkgPattern == "." { + return errSet(fmt.Errorf("%s%s is not within module rooted at %s", q.pattern, absDetail, modload.ModRoot())) + } + + match := modload.MatchInModule(ctx, pkgPattern, modload.Target, imports.AnyTags()) + if len(match.Errs) > 0 { + return pathSet{err: match.Errs[0]} + } + + if len(match.Pkgs) == 0 { + if q.raw == "" || q.raw == "." { + return errSet(fmt.Errorf("no package in current directory")) + } + if !q.isWildcard() { + return errSet(fmt.Errorf("%s%s is not a package in module rooted at %s", q.pattern, absDetail, modload.ModRoot())) + } + search.WarnUnmatched([]*search.Match{match}) + return pathSet{} + } + + return pathSet{pkgMods: []module.Version{modload.Target}} + }) + } +} + +// performWildcardQueries populates the candidates for each query whose pattern +// is a wildcard. +// +// The candidates for a given module path matching (or containing a package +// matching) a wildcard query depend only on the initial build list, but the set +// of modules may be expanded by other queries, so wildcard queries need to be +// re-evaluated whenever a potentially-matching module path is added to the +// build list. +func (r *resolver) performWildcardQueries(ctx context.Context) { + for _, q := range r.wildcardQueries { + q := q + r.work.Add(func() { + if q.version == "none" { + r.queryNone(ctx, q) + } else { + r.queryWildcard(ctx, q) + } + }) + } + <-r.work.Idle() +} + +// queryWildcard adds a candidate set to q for each module for which: +// - some version of the module is already in the build list, and +// - that module exists at some version matching q.version, and +// - either the module path itself matches q.pattern, or some package within +// the module at q.version matches q.pattern. +func (r *resolver) queryWildcard(ctx context.Context, q *query) { + // For wildcard patterns, modload.QueryPattern only identifies modules + // matching the prefix of the path before the wildcard. However, the build + // list may already contain other modules with matching packages, and we + // should consider those modules to satisfy the query too. + // We want to match any packages in existing dependencies, but we only want to + // resolve new dependencies if nothing else turns up. + for _, curM := range r.buildList { + if !q.canMatchInModule(curM.Path) { + continue + } + q.pathOnce(curM.Path, func() pathSet { + if _, hit := r.noneForPath(curM.Path); hit { + // This module is being removed, so it will no longer be in the build list + // (and thus will no longer match the pattern). + return pathSet{} + } + + if curM.Path == modload.Target.Path && !versionOkForMainModule(q.version) { + if q.matchesPath(curM.Path) { + return errSet(&modload.QueryMatchesMainModuleError{ + Pattern: q.pattern, + Query: q.version, + }) + } + + packages, err := r.matchInModule(ctx, q.pattern, curM) + if err != nil { + return errSet(err) + } + if len(packages) > 0 { + return errSet(&modload.QueryMatchesPackagesInMainModuleError{ + Pattern: q.pattern, + Query: q.version, + Packages: packages, + }) + } + + return r.tryWildcard(ctx, q, curM) + } + + m, err := r.queryModule(ctx, curM.Path, q.version, r.initialSelected) + if err != nil { + if !isNoSuchModuleVersion(err) { + // We can't tell whether a matching version exists. + return errSet(err) + } + // There is no version of curM.Path matching the query. + + // We haven't checked whether curM contains any matching packages at its + // currently-selected version, or whether curM.Path itself matches q. If + // either of those conditions holds, *and* no other query changes the + // selected version of curM, then we will fail in checkWildcardVersions. + // (This could be an error, but it's too soon to tell.) + // + // However, even then the transitive requirements of some other query + // may downgrade this module out of the build list entirely, in which + // case the pattern will no longer include it and it won't be an error. + // + // Either way, punt on the query rather than erroring out just yet. + return pathSet{} + } + + return r.tryWildcard(ctx, q, m) + }) + } + + // Even if no modules matched, we shouldn't query for a new module to provide + // the pattern yet: some other query may yet induce a new requirement that + // will match the wildcard. Instead, we'll check in findMissingWildcards. +} + +// tryWildcard returns a pathSet for module m matching query q. +// If m does not actually match q, tryWildcard returns an empty pathSet. +func (r *resolver) tryWildcard(ctx context.Context, q *query, m module.Version) pathSet { + mMatches := q.matchesPath(m.Path) + packages, err := r.matchInModule(ctx, q.pattern, m) + if err != nil { + return errSet(err) + } + if len(packages) > 0 { + return pathSet{pkgMods: []module.Version{m}} + } + if mMatches { + return pathSet{mod: m} + } + return pathSet{} +} + +// findMissingWildcards adds a candidate set for each query in r.wildcardQueries +// that has not yet resolved to any version containing packages. +func (r *resolver) findMissingWildcards(ctx context.Context) { + for _, q := range r.wildcardQueries { + if q.version == "none" || q.matchesPackages { + continue // q is not “missing” + } + r.work.Add(func() { + q.pathOnce(q.pattern, func() pathSet { + pkgMods, mod, err := r.queryPattern(ctx, q.pattern, q.version, r.initialSelected) + if err != nil { + if isNoSuchPackageVersion(err) && len(q.resolved) > 0 { + // q already resolved one or more modules but matches no packages. + // That's ok: this pattern is just a module pattern, and we don't + // need to add any more modules to satisfy it. + return pathSet{} + } + return errSet(err) + } + + return pathSet{pkgMods: pkgMods, mod: mod} + }) + }) + } + <-r.work.Idle() +} + +// checkWildcardVersions reports an error if any module in the build list has a +// path (or contains a package) matching a query with a wildcard pattern, but +// has a selected version that does *not* match the query. +func (r *resolver) checkWildcardVersions(ctx context.Context) { + defer base.ExitIfErrors() + + for _, q := range r.wildcardQueries { + for _, curM := range r.buildList { + if !q.canMatchInModule(curM.Path) { + continue + } + if !q.matchesPath(curM.Path) { + packages, err := r.matchInModule(ctx, q.pattern, curM) + if len(packages) == 0 { + if err != nil { + reportError(q, err) + } + continue // curM is not relevant to q. + } + } + + rev, err := r.queryModule(ctx, curM.Path, q.version, r.initialSelected) + if err != nil { + reportError(q, err) + continue + } + if rev.Version == curM.Version { + continue // curM already matches q. + } + + if !q.matchesPath(curM.Path) { + m := module.Version{Path: curM.Path, Version: rev.Version} + packages, err := r.matchInModule(ctx, q.pattern, m) + if err != nil { + reportError(q, err) + continue + } + if len(packages) == 0 { + // curM at its original version contains a path matching q.pattern, + // but at rev.Version it does not, so (somewhat paradoxically) if + // we changed the version of curM it would no longer match the query. + var version interface{} = m + if rev.Version != q.version { + version = fmt.Sprintf("%s@%s (%s)", m.Path, q.version, m.Version) + } + reportError(q, fmt.Errorf("%v matches packages in %v but not %v: specify a different version for module %s", q, curM, version, m.Path)) + continue + } + } + + // Since queryModule succeeded and either curM or one of the packages it + // contains matches q.pattern, we should have either selected the version + // of curM matching q, or reported a conflict error (and exited). + // If we're still here and the version doesn't match, + // something has gone very wrong. + reportError(q, fmt.Errorf("internal error: selected %v instead of %v", curM, rev.Version)) + } + } +} + +// performPathQueries populates the candidates for each query whose pattern is +// a path literal. +// +// The candidate packages and modules for path literals depend only on the +// initial build list, not the current build list, so we only need to query path +// literals once. +func (r *resolver) performPathQueries(ctx context.Context) { + for _, q := range r.pathQueries { + q := q + r.work.Add(func() { + if q.version == "none" { + r.queryNone(ctx, q) + } else { + r.queryPath(ctx, q) + } + }) + } + <-r.work.Idle() +} + +// queryPath adds a candidate set to q for the package with path q.pattern. +// The candidate set consists of all modules that could provide q.pattern +// and have a version matching q, plus (if it exists) the module whose path +// is itself q.pattern (at a matching version). +func (r *resolver) queryPath(ctx context.Context, q *query) { + q.pathOnce(q.pattern, func() pathSet { + if search.IsMetaPackage(q.pattern) || q.isWildcard() { + panic(fmt.Sprintf("internal error: queryPath called with pattern %q", q.pattern)) + } + if q.version == "none" { + panic(`internal error: queryPath called with version "none"`) + } + + if search.IsStandardImportPath(q.pattern) { + stdOnly := module.Version{} + packages, _ := r.matchInModule(ctx, q.pattern, stdOnly) + if len(packages) > 0 { + if q.rawVersion != "" { + return errSet(fmt.Errorf("can't request explicit version %q of standard library package %s", q.version, q.pattern)) + } + + q.matchesPackages = true + return pathSet{} // No module needed for standard library. + } + } + + pkgMods, mod, err := r.queryPattern(ctx, q.pattern, q.version, r.initialSelected) + if err != nil { + return errSet(err) + } + return pathSet{pkgMods: pkgMods, mod: mod} + }) +} + +// performPatternAllQueries populates the candidates for each query whose +// pattern is "all". +// +// The candidate modules for a given package in "all" depend only on the initial +// build list, but we cannot follow the dependencies of a given package until we +// know which candidate is selected — and that selection may depend on the +// results of other queries. We need to re-evaluate the "all" queries whenever +// the module for one or more packages in "all" are resolved. +func (r *resolver) performPatternAllQueries(ctx context.Context) { + if len(r.patternAllQueries) == 0 { + return + } + + findPackage := func(ctx context.Context, path string, m module.Version) (versionOk bool) { + versionOk = true + for _, q := range r.patternAllQueries { + q.pathOnce(path, func() pathSet { + pkgMods, err := r.queryPackages(ctx, path, q.version, r.initialSelected) + if len(pkgMods) != 1 || pkgMods[0] != m { + // There are candidates other than m for the given path, so we can't + // be certain that m will actually be the module selected to provide + // the package. Don't load its dependencies just yet, because they + // might no longer be dependencies after we resolve the correct + // version. + versionOk = false + } + return pathSet{pkgMods: pkgMods, err: err} + }) + } + return versionOk + } + + r.loadPackages(ctx, []string{"all"}, findPackage) + + // Since we built up the candidate lists concurrently, they may be in a + // nondeterministic order. We want 'go get' to be fully deterministic, + // including in which errors it chooses to report, so sort the candidates + // into a deterministic-but-arbitrary order. + for _, q := range r.patternAllQueries { + sort.Slice(q.candidates, func(i, j int) bool { + return q.candidates[i].path < q.candidates[j].path + }) + } +} + +// findAndUpgradeImports returns a pathSet for each package that is not yet +// in the build list but is transitively imported by the packages matching the +// given queries (which must already have been resolved). +// +// If the getU flag ("-u") is set, findAndUpgradeImports also returns a +// pathSet for each module that is not constrained by any other +// command-line argument and has an available matching upgrade. +func (r *resolver) findAndUpgradeImports(ctx context.Context, queries []*query) (upgrades []pathSet) { + patterns := make([]string, 0, len(queries)) + for _, q := range queries { + if q.matchesPackages { + patterns = append(patterns, q.pattern) + } + } + if len(patterns) == 0 { + return nil + } + + // mu guards concurrent writes to upgrades, which will be sorted + // (to restore determinism) after loading. + var mu sync.Mutex + + findPackage := func(ctx context.Context, path string, m module.Version) (versionOk bool) { + version := "latest" + if m.Path != "" { + if getU.version == "" { + // The user did not request that we upgrade transitive dependencies. + return true + } + if _, ok := r.resolvedVersion[m.Path]; ok { + // We cannot upgrade m implicitly because its version is determined by + // an explicit pattern argument. + return true + } + version = getU.version + } + + // Unlike other queries, the "-u" flag upgrades relative to the build list + // after applying changes so far, not the initial build list. + // This is for two reasons: + // + // - The "-u" flag intentionally applies to transitive dependencies, + // which may not be known or even resolved in advance of applying + // other version changes. + // + // - The "-u" flag, unlike other arguments, does not cause version + // conflicts with other queries. (The other query always wins.) + + pkgMods, err := r.queryPackages(ctx, path, version, r.selected) + for _, u := range pkgMods { + if u == m { + // The selected package version is already upgraded appropriately; there + // is no need to change it. + return true + } + } + + if err != nil { + if isNoSuchPackageVersion(err) || (m.Path == "" && module.CheckPath(path) != nil) { + // We can't find the package because it doesn't — or can't — even exist + // in any module at the latest version. (Note that invalid module paths + // could in general exist due to replacements, so we at least need to + // run the query to check those.) + // + // There is no version change we can make to fix the package, so leave + // it unresolved. Either some other query (perhaps a wildcard matching a + // newly-added dependency for some other missing package) will fill in + // the gaps, or we will report an error (with a better import stack) in + // the final LoadPackages call. + return true + } + } + + mu.Lock() + upgrades = append(upgrades, pathSet{path: path, pkgMods: pkgMods, err: err}) + mu.Unlock() + return false + } + + r.loadPackages(ctx, patterns, findPackage) + + // Since we built up the candidate lists concurrently, they may be in a + // nondeterministic order. We want 'go get' to be fully deterministic, + // including in which errors it chooses to report, so sort the candidates + // into a deterministic-but-arbitrary order. + sort.Slice(upgrades, func(i, j int) bool { + return upgrades[i].path < upgrades[j].path + }) + return upgrades +} + +// loadPackages loads the packages matching the given patterns, invoking the +// findPackage function for each package that may require a change to the +// build list. +// +// loadPackages invokes the findPackage function for each package loaded from a +// module outside the main module. If the module or version that supplies that +// package needs to be changed due to a query, findPackage may return false +// and the imports of that package will not be loaded. +// +// loadPackages also invokes the findPackage function for each imported package +// that is neither present in the standard library nor in any module in the +// build list. +func (r *resolver) loadPackages(ctx context.Context, patterns []string, findPackage func(ctx context.Context, path string, m module.Version) (versionOk bool)) { + opts := modload.PackageOpts{ + Tags: imports.AnyTags(), + LoadTests: *getT, + SilenceErrors: true, // May be fixed by subsequent upgrades or downgrades. + } + + opts.AllowPackage = func(ctx context.Context, path string, m module.Version) error { + if m.Path == "" || m == modload.Target { + // Packages in the standard library and main module are already at their + // latest (and only) available versions. + return nil + } + if ok := findPackage(ctx, path, m); !ok { + return errVersionChange + } + return nil + } + + _, pkgs := modload.LoadPackages(ctx, opts, patterns...) + for _, path := range pkgs { + const ( + parentPath = "" + parentIsStd = false + ) + _, _, err := modload.Lookup(parentPath, parentIsStd, path) + if err == nil { + continue + } + if errors.Is(err, errVersionChange) { + // We already added candidates during loading. + continue + } + + var ( + importMissing *modload.ImportMissingError + ambiguous *modload.AmbiguousImportError + ) + if !errors.As(err, &importMissing) && !errors.As(err, &ambiguous) { + // The package, which is a dependency of something we care about, has some + // problem that we can't resolve with a version change. + // Leave the error for the final LoadPackages call. + continue + } + + path := path + r.work.Add(func() { + findPackage(ctx, path, module.Version{}) + }) + } + <-r.work.Idle() +} + +// errVersionChange is a sentinel error indicating that a module's version needs +// to be updated before its dependencies can be loaded. +var errVersionChange = errors.New("version change needed") + +// resolveCandidates resolves candidates sets that are attached to the given +// queries and/or needed to provide the given missing-package dependencies. +// +// resolveCandidates starts by resolving one module version from each +// unambiguous pathSet attached to the given queries. +// +// If no unambiguous query results in a change to the build list, +// resolveCandidates modifies the build list by adding one module version from +// each pathSet in missing, but does not mark those versions as resolved +// (so they can still be modified by other queries). +// +// If that still does not result in any changes to the build list, +// resolveCandidates revisits the ambiguous query candidates and resolves them +// arbitrarily in order to guarantee forward progress. +// +// If all pathSets are resolved without any changes to the build list, +// resolveCandidates returns with changed=false. +func (r *resolver) resolveCandidates(ctx context.Context, queries []*query, upgrades []pathSet) (changed bool) { + defer base.ExitIfErrors() + + // Note: this is O(N²) with the number of pathSets in the worst case. + // + // We could perhaps get it down to O(N) if we were to index the pathSets + // by module path, so that we only revisit a given pathSet when the + // version of some module in its containingPackage list has been determined. + // + // However, N tends to be small, and most candidate sets will include only one + // candidate module (so they will be resolved in the first iteration), so for + // now we'll stick to the simple O(N²) approach. + + resolved := 0 + for { + prevResolved := resolved + + for _, q := range queries { + unresolved := q.candidates[:0] + + for _, cs := range q.candidates { + if cs.err != nil { + reportError(q, cs.err) + resolved++ + continue + } + + filtered, isPackage, m, unique := r.disambiguate(cs) + if !unique { + unresolved = append(unresolved, filtered) + continue + } + + if m.Path == "" { + // The query is not viable. Choose an arbitrary candidate from + // before filtering and “resolve” it to report a conflict. + isPackage, m = r.chooseArbitrarily(cs) + } + if isPackage { + q.matchesPackages = true + } + r.resolve(q, m) + resolved++ + } + + q.candidates = unresolved + } + + base.ExitIfErrors() + if resolved == prevResolved { + break // No unambiguous candidate remains. + } + } + + if changed := r.updateBuildList(ctx, nil); changed { + // The build list has changed, so disregard any missing packages: they might + // now be determined by requirements in the build list, which we would + // prefer to use instead of arbitrary "latest" versions. + return true + } + + // Arbitrarily add a "latest" version that provides each missing package, but + // do not mark the version as resolved: we still want to allow the explicit + // queries to modify the resulting versions. + var tentative []module.Version + for _, cs := range upgrades { + if cs.err != nil { + base.Errorf("go get: %v", cs.err) + continue + } + + filtered, _, m, unique := r.disambiguate(cs) + if !unique { + _, m = r.chooseArbitrarily(filtered) + } + if m.Path == "" { + // There is no viable candidate for the missing package. + // Leave it unresolved. + continue + } + tentative = append(tentative, m) + } + base.ExitIfErrors() + if changed := r.updateBuildList(ctx, tentative); changed { + return true + } + + // The build list will be the same on the next iteration as it was on this + // iteration, so any ambiguous queries will remain so. In order to make + // progress, resolve them arbitrarily but deterministically. + // + // If that results in conflicting versions, the user can re-run 'go get' + // with additional explicit versions for the conflicting packages or + // modules. + for _, q := range queries { + for _, cs := range q.candidates { + isPackage, m := r.chooseArbitrarily(cs) + if isPackage { + q.matchesPackages = true + } + r.resolve(q, m) + } + } + return r.updateBuildList(ctx, nil) +} + +// disambiguate eliminates candidates from cs that conflict with other module +// versions that have already been resolved. If there is only one (unique) +// remaining candidate, disambiguate returns that candidate, along with +// an indication of whether that result interprets cs.path as a package +// +// Note: we're only doing very simple disambiguation here. The goal is to +// reproduce the user's intent, not to find a solution that a human couldn't. +// In the vast majority of cases, we expect only one module per pathSet, +// but we want to give some minimal additional tools so that users can add an +// extra argument or two on the command line to resolve simple ambiguities. +func (r *resolver) disambiguate(cs pathSet) (filtered pathSet, isPackage bool, m module.Version, unique bool) { + if len(cs.pkgMods) == 0 && cs.mod.Path == "" { + panic("internal error: resolveIfUnambiguous called with empty pathSet") + } + + for _, m := range cs.pkgMods { + if _, ok := r.noneForPath(m.Path); ok { + // A query with version "none" forces the candidate module to version + // "none", so we cannot use any other version for that module. + continue + } + + if m.Path == modload.Target.Path { + if m.Version == modload.Target.Version { + return pathSet{}, true, m, true + } + // The main module can only be set to its own version. + continue + } + + vr, ok := r.resolvedVersion[m.Path] + if !ok { + // m is a viable answer to the query, but other answers may also + // still be viable. + filtered.pkgMods = append(filtered.pkgMods, m) + continue + } + + if vr.version != m.Version { + // Some query forces the candidate module to a version other than this + // one. + // + // The command could be something like + // + // go get example.com/foo/bar@none example.com/foo/bar/baz@latest + // + // in which case we *cannot* resolve the package from + // example.com/foo/bar (because it is constrained to version + // "none") and must fall through to module example.com/foo@latest. + continue + } + + // Some query forces the candidate module *to* the candidate version. + // As a result, this candidate is the only viable choice to provide + // its package(s): any other choice would result in an ambiguous import + // for this path. + // + // For example, consider the command + // + // go get example.com/foo@latest example.com/foo/bar/baz@latest + // + // If modules example.com/foo and example.com/foo/bar both provide + // package example.com/foo/bar/baz, then we *must* resolve the package + // from example.com/foo: if we instead resolved it from + // example.com/foo/bar, we would have two copies of the package. + return pathSet{}, true, m, true + } + + if cs.mod.Path != "" { + vr, ok := r.resolvedVersion[cs.mod.Path] + if !ok || vr.version == cs.mod.Version { + filtered.mod = cs.mod + } + } + + if len(filtered.pkgMods) == 1 && + (filtered.mod.Path == "" || filtered.mod == filtered.pkgMods[0]) { + // Exactly one viable module contains the package with the given path + // (by far the common case), so we can resolve it unambiguously. + return pathSet{}, true, filtered.pkgMods[0], true + } + + if len(filtered.pkgMods) == 0 { + // All modules that could provide the path as a package conflict with other + // resolved arguments. If it can refer to a module instead, return that; + // otherwise, this pathSet cannot be resolved (and we will return the + // zero module.Version). + return pathSet{}, false, filtered.mod, true + } + + // The query remains ambiguous: there are at least two different modules + // to which cs.path could refer. + return filtered, false, module.Version{}, false +} + +// chooseArbitrarily returns an arbitrary (but deterministic) module version +// from among those in the given set. +// +// chooseArbitrarily prefers module paths that were already in the build list at +// the start of 'go get', prefers modules that provide packages over those that +// do not, and chooses the first module meeting those criteria (so biases toward +// longer paths). +func (r *resolver) chooseArbitrarily(cs pathSet) (isPackage bool, m module.Version) { + // Prefer to upgrade some module that was already in the build list. + for _, m := range cs.pkgMods { + if r.initialSelected(m.Path) != "none" { + return true, m + } + } + + // Otherwise, arbitrarily choose the first module that provides the package. + if len(cs.pkgMods) > 0 { + return true, cs.pkgMods[0] + } + + return false, cs.mod +} + +// checkPackagesAndRetractions reloads packages for the given patterns and +// reports missing and ambiguous package errors. It also reports loads and +// reports retractions for resolved modules and modules needed to build +// named packages. +// +// We skip missing-package errors earlier in the process, since we want to +// resolve pathSets ourselves, but at that point, we don't have enough context +// to log the package-import chains leading to each error. +func (r *resolver) checkPackagesAndRetractions(ctx context.Context, pkgPatterns []string) { + defer base.ExitIfErrors() + + // Build a list of modules to load retractions for. Start with versions + // selected based on command line queries. + // + // This is a subset of the build list. If the main module has a lot of + // dependencies, loading retractions for the entire build list would be slow. + relevantMods := make(map[module.Version]struct{}) + for path, reason := range r.resolvedVersion { + relevantMods[module.Version{Path: path, Version: reason.version}] = struct{}{} + } + + // Reload packages, reporting errors for missing and ambiguous imports. + if len(pkgPatterns) > 0 { + // LoadPackages will print errors (since it has more context) but will not + // exit, since we need to load retractions later. + pkgOpts := modload.PackageOpts{ + LoadTests: *getT, + ResolveMissingImports: false, + AllowErrors: true, + } + matches, pkgs := modload.LoadPackages(ctx, pkgOpts, pkgPatterns...) + for _, m := range matches { + if len(m.Errs) > 0 { + base.SetExitStatus(1) + break + } + } + for _, pkg := range pkgs { + if dir, _, err := modload.Lookup("", false, pkg); err != nil { + if dir != "" && errors.Is(err, imports.ErrNoGo) { + // Since dir is non-empty, we must have located source files + // associated with either the package or its test — ErrNoGo must + // indicate that none of those source files happen to apply in this + // configuration. If we are actually building the package (no -d + // flag), the compiler will report the problem; otherwise, assume that + // the user is going to build or test it in some other configuration + // and suppress the error. + continue + } + + base.SetExitStatus(1) + if ambiguousErr := (*modload.AmbiguousImportError)(nil); errors.As(err, &ambiguousErr) { + for _, m := range ambiguousErr.Modules { + relevantMods[m] = struct{}{} + } + } + } + if m := modload.PackageModule(pkg); m.Path != "" { + relevantMods[m] = struct{}{} + } + } + } + + // Load and report retractions. + type retraction struct { + m module.Version + err error + } + retractions := make([]retraction, 0, len(relevantMods)) + for m := range relevantMods { + retractions = append(retractions, retraction{m: m}) + } + sort.Slice(retractions, func(i, j int) bool { + return retractions[i].m.Path < retractions[j].m.Path + }) + for i := 0; i < len(retractions); i++ { + i := i + r.work.Add(func() { + err := modload.CheckRetractions(ctx, retractions[i].m) + if retractErr := (*modload.ModuleRetractedError)(nil); errors.As(err, &retractErr) { + retractions[i].err = err + } + }) + } + <-r.work.Idle() + var retractPath string + for _, r := range retractions { + if r.err != nil { + fmt.Fprintf(os.Stderr, "go: warning: %v\n", r.err) + if retractPath == "" { + retractPath = r.m.Path + } else { + retractPath = "<module>" + } + } + } + if retractPath != "" { + fmt.Fprintf(os.Stderr, "go: to switch to the latest unretracted version, run:\n\tgo get %s@latest\n", retractPath) + } +} + +// reportChanges logs version changes to os.Stderr. +// +// reportChanges only logs changes to modules named on the command line and to +// explicitly required modules in go.mod. Most changes to indirect requirements +// are not relevant to the user and are not logged. +// +// reportChanges should be called after WriteGoMod. +func (r *resolver) reportChanges(oldReqs, newReqs []module.Version) { + type change struct { + path, old, new string + } + changes := make(map[string]change) + + // Collect changes in modules matched by command line arguments. + for path, reason := range r.resolvedVersion { + old := r.initialVersion[path] + new := reason.version + if old != new && (old != "" || new != "none") { + changes[path] = change{path, old, new} + } + } + + // Collect changes to explicit requirements in go.mod. + for _, req := range oldReqs { + path := req.Path + old := req.Version + new := r.buildListVersion[path] + if old != new { + changes[path] = change{path, old, new} + } + } + for _, req := range newReqs { + path := req.Path + old := r.initialVersion[path] + new := req.Version + if old != new { + changes[path] = change{path, old, new} + } + } + + sortedChanges := make([]change, 0, len(changes)) + for _, c := range changes { + sortedChanges = append(sortedChanges, c) + } + sort.Slice(sortedChanges, func(i, j int) bool { + return sortedChanges[i].path < sortedChanges[j].path + }) + for _, c := range sortedChanges { + if c.old == "" { + fmt.Fprintf(os.Stderr, "go get: added %s %s\n", c.path, c.new) + } else if c.new == "none" || c.new == "" { + fmt.Fprintf(os.Stderr, "go get: removed %s %s\n", c.path, c.old) + } else if semver.Compare(c.new, c.old) > 0 { + fmt.Fprintf(os.Stderr, "go get: upgraded %s %s => %s\n", c.path, c.old, c.new) + } else { + fmt.Fprintf(os.Stderr, "go get: downgraded %s %s => %s\n", c.path, c.old, c.new) + } + } + + // TODO(golang.org/issue/33284): attribute changes to command line arguments. + // For modules matched by command line arguments, this probably isn't + // necessary, but it would be useful for unmatched direct dependencies of + // the main module. +} + +// resolve records that module m must be at its indicated version (which may be +// "none") due to query q. If some other query forces module m to be at a +// different version, resolve reports a conflict error. +func (r *resolver) resolve(q *query, m module.Version) { + if m.Path == "" { + panic("internal error: resolving a module.Version with an empty path") + } + + if m.Path == modload.Target.Path && m.Version != modload.Target.Version { + reportError(q, &modload.QueryMatchesMainModuleError{ + Pattern: q.pattern, + Query: q.version, + }) + return + } + + vr, ok := r.resolvedVersion[m.Path] + if ok && vr.version != m.Version { + reportConflict(q, m, vr) + return + } + r.resolvedVersion[m.Path] = versionReason{m.Version, q} + q.resolved = append(q.resolved, m) +} + +// updateBuildList updates the module loader's global build list to be +// consistent with r.resolvedVersion, and to include additional modules +// provided that they do not conflict with the resolved versions. +// +// If the additional modules conflict with the resolved versions, they will be +// downgraded to a non-conflicting version (possibly "none"). +func (r *resolver) updateBuildList(ctx context.Context, additions []module.Version) (changed bool) { + if len(additions) == 0 && len(r.resolvedVersion) == r.buildListResolvedVersions { + return false + } + + defer base.ExitIfErrors() + + resolved := make([]module.Version, 0, len(r.resolvedVersion)) + for mPath, rv := range r.resolvedVersion { + if mPath != modload.Target.Path { + resolved = append(resolved, module.Version{Path: mPath, Version: rv.version}) + } + } + + if err := modload.EditBuildList(ctx, additions, resolved); err != nil { + var constraint *modload.ConstraintError + if !errors.As(err, &constraint) { + base.Errorf("go get: %v", err) + return false + } + + reason := func(m module.Version) string { + rv, ok := r.resolvedVersion[m.Path] + if !ok { + panic(fmt.Sprintf("internal error: can't find reason for requirement on %v", m)) + } + return rv.reason.ResolvedString(module.Version{Path: m.Path, Version: rv.version}) + } + for _, c := range constraint.Conflicts { + base.Errorf("go get: %v requires %v, not %v", reason(c.Source), c.Dep, reason(c.Constraint)) + } + return false + } + + buildList := modload.LoadAllModules(ctx) + r.buildListResolvedVersions = len(r.resolvedVersion) + if reflect.DeepEqual(r.buildList, buildList) { + return false + } + r.buildList = buildList + r.buildListVersion = make(map[string]string, len(r.buildList)) + for _, m := range r.buildList { + r.buildListVersion[m.Path] = m.Version + } + return true +} + +func reqsFromGoMod(f *modfile.File) []module.Version { + reqs := make([]module.Version, len(f.Require)) + for i, r := range f.Require { + reqs[i] = r.Mod + } + return reqs +} + +// isNoSuchModuleVersion reports whether err indicates that the requested module +// does not exist at the requested version, either because the module does not +// exist at all or because it does not include that specific version. +func isNoSuchModuleVersion(err error) bool { + var noMatch *modload.NoMatchingVersionError + return errors.Is(err, os.ErrNotExist) || errors.As(err, &noMatch) +} + +// isNoSuchPackageVersion reports whether err indicates that the requested +// package does not exist at the requested version, either because no module +// that could contain it exists at that version, or because every such module +// that does exist does not actually contain the package. +func isNoSuchPackageVersion(err error) bool { + var noPackage *modload.PackageNotInModuleError + return isNoSuchModuleVersion(err) || errors.As(err, &noPackage) +} diff --git a/src/cmd/go/internal/modget/query.go b/src/cmd/go/internal/modget/query.go new file mode 100644 index 0000000..1a5a60f --- /dev/null +++ b/src/cmd/go/internal/modget/query.go @@ -0,0 +1,357 @@ +// Copyright 2020 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package modget + +import ( + "fmt" + "path/filepath" + "regexp" + "strings" + "sync" + + "cmd/go/internal/base" + "cmd/go/internal/modload" + "cmd/go/internal/search" + "cmd/go/internal/str" + + "golang.org/x/mod/module" +) + +// A query describes a command-line argument and the modules and/or packages +// to which that argument may resolve.. +type query struct { + // raw is the original argument, to be printed in error messages. + raw string + + // rawVersion is the portion of raw corresponding to version, if any + rawVersion string + + // pattern is the part of the argument before "@" (or the whole argument + // if there is no "@"), which may match either packages (preferred) or + // modules (if no matching packages). + // + // The pattern may also be "-u", for the synthetic query representing the -u + // (“upgrade”)flag. + pattern string + + // patternIsLocal indicates whether pattern is restricted to match only paths + // local to the main module, such as absolute filesystem paths or paths + // beginning with './'. + // + // A local pattern must resolve to one or more packages in the main module. + patternIsLocal bool + + // version is the part of the argument after "@", or an implied + // "upgrade" or "patch" if there is no "@". version specifies the + // module version to get. + version string + + // matchWildcard, if non-nil, reports whether pattern, which must be a + // wildcard (with the substring "..."), matches the given package or module + // path. + matchWildcard func(path string) bool + + // canMatchWildcard, if non-nil, reports whether the module with the given + // path could lexically contain a package matching pattern, which must be a + // wildcard. + canMatchWildcardInModule func(mPath string) bool + + // conflict is the first query identified as incompatible with this one. + // conflict forces one or more of the modules matching this query to a + // version that does not match version. + conflict *query + + // candidates is a list of sets of alternatives for a path that matches (or + // contains packages that match) the pattern. The query can be resolved by + // choosing exactly one alternative from each set in the list. + // + // A path-literal query results in only one set: the path itself, which + // may resolve to either a package path or a module path. + // + // A wildcard query results in one set for each matching module path, each + // module for which the matching version contains at least one matching + // package, and (if no other modules match) one candidate set for the pattern + // overall if no existing match is identified in the build list. + // + // A query for pattern "all" results in one set for each package transitively + // imported by the main module. + // + // The special query for the "-u" flag results in one set for each + // otherwise-unconstrained package that has available upgrades. + candidates []pathSet + candidatesMu sync.Mutex + + // pathSeen ensures that only one pathSet is added to the query per + // unique path. + pathSeen sync.Map + + // resolved contains the set of modules whose versions have been determined by + // this query, in the order in which they were determined. + // + // The resolver examines the candidate sets for each query, resolving one + // module per candidate set in a way that attempts to avoid obvious conflicts + // between the versions resolved by different queries. + resolved []module.Version + + // matchesPackages is true if the resolved modules provide at least one + // package mathcing q.pattern. + matchesPackages bool +} + +// A pathSet describes the possible options for resolving a specific path +// to a package and/or module. +type pathSet struct { + // path is a package (if "all" or "-u" or a non-wildcard) or module (if + // wildcard) path that could be resolved by adding any of the modules in this + // set. For a wildcard pattern that so far matches no packages, the path is + // the wildcard pattern itself. + // + // Each path must occur only once in a query's candidate sets, and the path is + // added implicitly to each pathSet returned to pathOnce. + path string + + // pkgMods is a set of zero or more modules, each of which contains the + // package with the indicated path. Due to the requirement that imports be + // unambiguous, only one such module can be in the build list, and all others + // must be excluded. + pkgMods []module.Version + + // mod is either the zero Version, or a module that does not contain any + // packages matching the query but for which the module path itself + // matches the query pattern. + // + // We track this module separately from pkgMods because, all else equal, we + // prefer to match a query to a package rather than just a module. Also, + // unlike the modules in pkgMods, this module does not inherently exclude + // any other module in pkgMods. + mod module.Version + + err error +} + +// errSet returns a pathSet containing the given error. +func errSet(err error) pathSet { return pathSet{err: err} } + +// newQuery returns a new query parsed from the raw argument, +// which must be either path or path@version. +func newQuery(raw string) (*query, error) { + pattern := raw + rawVers := "" + if i := strings.Index(raw, "@"); i >= 0 { + pattern, rawVers = raw[:i], raw[i+1:] + if strings.Contains(rawVers, "@") || rawVers == "" { + return nil, fmt.Errorf("invalid module version syntax %q", raw) + } + } + + // If no version suffix is specified, assume @upgrade. + // If -u=patch was specified, assume @patch instead. + version := rawVers + if version == "" { + if getU.version == "" { + version = "upgrade" + } else { + version = getU.version + } + } + + q := &query{ + raw: raw, + rawVersion: rawVers, + pattern: pattern, + patternIsLocal: filepath.IsAbs(pattern) || search.IsRelativePath(pattern), + version: version, + } + if strings.Contains(q.pattern, "...") { + q.matchWildcard = search.MatchPattern(q.pattern) + q.canMatchWildcardInModule = search.TreeCanMatchPattern(q.pattern) + } + if err := q.validate(); err != nil { + return q, err + } + return q, nil +} + +// validate reports a non-nil error if q is not sensible and well-formed. +func (q *query) validate() error { + if q.patternIsLocal { + if q.rawVersion != "" { + return fmt.Errorf("can't request explicit version %q of path %q in main module", q.rawVersion, q.pattern) + } + return nil + } + + if q.pattern == "all" { + // If there is no main module, "all" is not meaningful. + if !modload.HasModRoot() { + return fmt.Errorf(`cannot match "all": %v`, modload.ErrNoModRoot) + } + if !versionOkForMainModule(q.version) { + // TODO(bcmills): "all@none" seems like a totally reasonable way to + // request that we remove all module requirements, leaving only the main + // module and standard library. Perhaps we should implement that someday. + return &modload.QueryMatchesMainModuleError{ + Pattern: q.pattern, + Query: q.version, + } + } + } + + if search.IsMetaPackage(q.pattern) && q.pattern != "all" { + if q.pattern != q.raw { + return fmt.Errorf("can't request explicit version of standard-library pattern %q", q.pattern) + } + } + + return nil +} + +// String returns the original argument from which q was parsed. +func (q *query) String() string { return q.raw } + +// ResolvedString returns a string describing m as a resolved match for q. +func (q *query) ResolvedString(m module.Version) string { + if m.Path != q.pattern { + if m.Version != q.version { + return fmt.Sprintf("%v (matching %s@%s)", m, q.pattern, q.version) + } + return fmt.Sprintf("%v (matching %v)", m, q) + } + if m.Version != q.version { + return fmt.Sprintf("%s@%s (%s)", q.pattern, q.version, m.Version) + } + return q.String() +} + +// isWildcard reports whether q is a pattern that can match multiple paths. +func (q *query) isWildcard() bool { + return q.matchWildcard != nil || (q.patternIsLocal && strings.Contains(q.pattern, "...")) +} + +// matchesPath reports whether the given path matches q.pattern. +func (q *query) matchesPath(path string) bool { + if q.matchWildcard != nil { + return q.matchWildcard(path) + } + return path == q.pattern +} + +// canMatchInModule reports whether the given module path can potentially +// contain q.pattern. +func (q *query) canMatchInModule(mPath string) bool { + if q.canMatchWildcardInModule != nil { + return q.canMatchWildcardInModule(mPath) + } + return str.HasPathPrefix(q.pattern, mPath) +} + +// pathOnce invokes f to generate the pathSet for the given path, +// if one is still needed. +// +// Note that, unlike sync.Once, pathOnce does not guarantee that a concurrent +// call to f for the given path has completed on return. +// +// pathOnce is safe for concurrent use by multiple goroutines, but note that +// multiple concurrent calls will result in the sets being added in +// nondeterministic order. +func (q *query) pathOnce(path string, f func() pathSet) { + if _, dup := q.pathSeen.LoadOrStore(path, nil); dup { + return + } + + cs := f() + + if len(cs.pkgMods) > 0 || cs.mod != (module.Version{}) || cs.err != nil { + cs.path = path + q.candidatesMu.Lock() + q.candidates = append(q.candidates, cs) + q.candidatesMu.Unlock() + } +} + +// reportError logs err concisely using base.Errorf. +func reportError(q *query, err error) { + errStr := err.Error() + + // If err already mentions all of the relevant parts of q, just log err to + // reduce stutter. Otherwise, log both q and err. + // + // TODO(bcmills): Use errors.As to unpack these errors instead of parsing + // strings with regular expressions. + + patternRE := regexp.MustCompile("(?m)(?:[ \t(\"`]|^)" + regexp.QuoteMeta(q.pattern) + "(?:[ @:;)\"`]|$)") + if patternRE.MatchString(errStr) { + if q.rawVersion == "" { + base.Errorf("go get: %s", errStr) + return + } + + versionRE := regexp.MustCompile("(?m)(?:[ @(\"`]|^)" + regexp.QuoteMeta(q.version) + "(?:[ :;)\"`]|$)") + if versionRE.MatchString(errStr) { + base.Errorf("go get: %s", errStr) + return + } + } + + if qs := q.String(); qs != "" { + base.Errorf("go get %s: %s", qs, errStr) + } else { + base.Errorf("go get: %s", errStr) + } +} + +func reportConflict(pq *query, m module.Version, conflict versionReason) { + if pq.conflict != nil { + // We've already reported a conflict for the proposed query. + // Don't report it again, even if it has other conflicts. + return + } + pq.conflict = conflict.reason + + proposed := versionReason{ + version: m.Version, + reason: pq, + } + if pq.isWildcard() && !conflict.reason.isWildcard() { + // Prefer to report the specific path first and the wildcard second. + proposed, conflict = conflict, proposed + } + reportError(pq, &conflictError{ + mPath: m.Path, + proposed: proposed, + conflict: conflict, + }) +} + +type conflictError struct { + mPath string + proposed versionReason + conflict versionReason +} + +func (e *conflictError) Error() string { + argStr := func(q *query, v string) string { + if v != q.version { + return fmt.Sprintf("%s@%s (%s)", q.pattern, q.version, v) + } + return q.String() + } + + pq := e.proposed.reason + rq := e.conflict.reason + modDetail := "" + if e.mPath != pq.pattern { + modDetail = fmt.Sprintf("for module %s, ", e.mPath) + } + + return fmt.Sprintf("%s%s conflicts with %s", + modDetail, + argStr(pq, e.proposed.version), + argStr(rq, e.conflict.version)) +} + +func versionOkForMainModule(version string) bool { + return version == "upgrade" || version == "patch" +} |