Adding upstream version 1.20.14.upstream/1.20.14upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 411 insertions, 0 deletions

diff --git a/src/cmd/go/internal/modfetch/repo.go b/src/cmd/go/internal/modfetch/repo.go
new file mode 100644
index 0000000..d4c57bb
--- /dev/null
+++ b/src/cmd/go/internal/modfetch/repo.go
@@ -0,0 +1,411 @@
+// 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 modfetch
+
+import (
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"strconv"
+	"time"
+
+	"cmd/go/internal/cfg"
+	"cmd/go/internal/modfetch/codehost"
+	"cmd/go/internal/par"
+	"cmd/go/internal/vcs"
+	web "cmd/go/internal/web"
+
+	"golang.org/x/mod/module"
+)
+
+const traceRepo = false // trace all repo actions, for debugging
+
+// A Repo represents a repository storing all versions of a single module.
+// It must be safe for simultaneous use by multiple goroutines.
+type Repo interface {
+	// ModulePath returns the module path.
+	ModulePath() string
+
+	// CheckReuse checks whether the validation criteria in the origin
+	// are still satisfied on the server corresponding to this module.
+	// If so, the caller can reuse any cached Versions or RevInfo containing
+	// this origin rather than redownloading those from the server.
+	CheckReuse(old *codehost.Origin) error
+
+	// Versions lists all known versions with the given prefix.
+	// Pseudo-versions are not included.
+	//
+	// Versions should be returned sorted in semver order
+	// (implementations can use semver.Sort).
+	//
+	// Versions returns a non-nil error only if there was a problem
+	// fetching the list of versions: it may return an empty list
+	// along with a nil error if the list of matching versions
+	// is known to be empty.
+	//
+	// If the underlying repository does not exist,
+	// Versions returns an error matching errors.Is(_, os.NotExist).
+	Versions(prefix string) (*Versions, error)
+
+	// Stat returns information about the revision rev.
+	// A revision can be any identifier known to the underlying service:
+	// commit hash, branch, tag, and so on.
+	Stat(rev string) (*RevInfo, error)
+
+	// Latest returns the latest revision on the default branch,
+	// whatever that means in the underlying source code repository.
+	// It is only used when there are no tagged versions.
+	Latest() (*RevInfo, error)
+
+	// GoMod returns the go.mod file for the given version.
+	GoMod(version string) (data []byte, err error)
+
+	// Zip writes a zip file for the given version to dst.
+	Zip(dst io.Writer, version string) error
+}
+
+// A Versions describes the available versions in a module repository.
+type Versions struct {
+	Origin *codehost.Origin `json:",omitempty"` // origin information for reuse
+
+	List []string // semver versions
+}
+
+// A RevInfo describes a single revision in a module repository.
+type RevInfo struct {
+	Version string    // suggested version string for this revision
+	Time    time.Time // commit time
+
+	// These fields are used for Stat of arbitrary rev,
+	// but they are not recorded when talking about module versions.
+	Name  string `json:"-"` // complete ID in underlying repository
+	Short string `json:"-"` // shortened ID, for use in pseudo-version
+
+	Origin *codehost.Origin `json:",omitempty"` // provenance for reuse
+}
+
+// Re: module paths, import paths, repository roots, and lookups
+//
+// A module is a collection of Go packages stored in a file tree
+// with a go.mod file at the root of the tree.
+// The go.mod defines the module path, which is the import path
+// corresponding to the root of the file tree.
+// The import path of a directory within that file tree is the module path
+// joined with the name of the subdirectory relative to the root.
+//
+// For example, the module with path rsc.io/qr corresponds to the
+// file tree in the repository https://github.com/rsc/qr.
+// That file tree has a go.mod that says "module rsc.io/qr".
+// The package in the root directory has import path "rsc.io/qr".
+// The package in the gf256 subdirectory has import path "rsc.io/qr/gf256".
+// In this example, "rsc.io/qr" is both a module path and an import path.
+// But "rsc.io/qr/gf256" is only an import path, not a module path:
+// it names an importable package, but not a module.
+//
+// As a special case to incorporate code written before modules were
+// introduced, if a path p resolves using the pre-module "go get" lookup
+// to the root of a source code repository without a go.mod file,
+// that repository is treated as if it had a go.mod in its root directory
+// declaring module path p. (The go.mod is further considered to
+// contain requirements corresponding to any legacy version
+// tracking format such as Gopkg.lock, vendor/vendor.conf, and so on.)
+//
+// The presentation so far ignores the fact that a source code repository
+// has many different versions of a file tree, and those versions may
+// differ in whether a particular go.mod exists and what it contains.
+// In fact there is a well-defined mapping only from a module path, version
+// pair - often written path@version - to a particular file tree.
+// For example rsc.io/qr@v0.1.0 depends on the "implicit go.mod at root of
+// repository" rule, while rsc.io/qr@v0.2.0 has an explicit go.mod.
+// Because the "go get" import paths rsc.io/qr and github.com/rsc/qr
+// both redirect to the Git repository https://github.com/rsc/qr,
+// github.com/rsc/qr@v0.1.0 is the same file tree as rsc.io/qr@v0.1.0
+// but a different module (a different name). In contrast, since v0.2.0
+// of that repository has an explicit go.mod that declares path rsc.io/qr,
+// github.com/rsc/qr@v0.2.0 is an invalid module path, version pair.
+// Before modules, import comments would have had the same effect.
+//
+// The set of import paths associated with a given module path is
+// clearly not fixed: at the least, new directories with new import paths
+// can always be added. But another potential operation is to split a
+// subtree out of a module into its own module. If done carefully,
+// this operation can be done while preserving compatibility for clients.
+// For example, suppose that we want to split rsc.io/qr/gf256 into its
+// own module, so that there would be two modules rsc.io/qr and rsc.io/qr/gf256.
+// Then we can simultaneously issue rsc.io/qr v0.3.0 (dropping the gf256 subdirectory)
+// and rsc.io/qr/gf256 v0.1.0, including in their respective go.mod
+// cyclic requirements pointing at each other: rsc.io/qr v0.3.0 requires
+// rsc.io/qr/gf256 v0.1.0 and vice versa. Then a build can be
+// using an older rsc.io/qr module that includes the gf256 package, but if
+// it adds a requirement on either the newer rsc.io/qr or the newer
+// rsc.io/qr/gf256 module, it will automatically add the requirement
+// on the complementary half, ensuring both that rsc.io/qr/gf256 is
+// available for importing by the build and also that it is only defined
+// by a single module. The gf256 package could move back into the
+// original by another simultaneous release of rsc.io/qr v0.4.0 including
+// the gf256 subdirectory and an rsc.io/qr/gf256 v0.2.0 with no code
+// in its root directory, along with a new requirement cycle.
+// The ability to shift module boundaries in this way is expected to be
+// important in large-scale program refactorings, similar to the ones
+// described in https://talks.golang.org/2016/refactor.article.
+//
+// The possibility of shifting module boundaries reemphasizes
+// that you must know both the module path and its version
+// to determine the set of packages provided directly by that module.
+//
+// On top of all this, it is possible for a single code repository
+// to contain multiple modules, either in branches or subdirectories,
+// as a limited kind of monorepo. For example rsc.io/qr/v2,
+// the v2.x.x continuation of rsc.io/qr, is expected to be found
+// in v2-tagged commits in https://github.com/rsc/qr, either
+// in the root or in a v2 subdirectory, disambiguated by go.mod.
+// Again the precise file tree corresponding to a module
+// depends on which version we are considering.
+//
+// It is also possible for the underlying repository to change over time,
+// without changing the module path. If I copy the github repo over
+// to https://bitbucket.org/rsc/qr and update https://rsc.io/qr?go-get=1,
+// then clients of all versions should start fetching from bitbucket
+// instead of github. That is, in contrast to the exact file tree,
+// the location of the source code repository associated with a module path
+// does not depend on the module version. (This is by design, as the whole
+// point of these redirects is to allow package authors to establish a stable
+// name that can be updated as code moves from one service to another.)
+//
+// All of this is important background for the lookup APIs defined in this
+// file.
+//
+// The Lookup function takes a module path and returns a Repo representing
+// that module path. Lookup can do only a little with the path alone.
+// It can check that the path is well-formed (see semver.CheckPath)
+// and it can check that the path can be resolved to a target repository.
+// To avoid version control access except when absolutely necessary,
+// Lookup does not attempt to connect to the repository itself.
+
+var lookupCache par.Cache
+
+type lookupCacheKey struct {
+	proxy, path string
+}
+
+// Lookup returns the module with the given module path,
+// fetched through the given proxy.
+//
+// The distinguished proxy "direct" indicates that the path should be fetched
+// from its origin, and "noproxy" indicates that the patch should be fetched
+// directly only if GONOPROXY matches the given path.
+//
+// For the distinguished proxy "off", Lookup always returns a Repo that returns
+// a non-nil error for every method call.
+//
+// A successful return does not guarantee that the module
+// has any defined versions.
+func Lookup(proxy, path string) Repo {
+	if traceRepo {
+		defer logCall("Lookup(%q, %q)", proxy, path)()
+	}
+
+	type cached struct {
+		r Repo
+	}
+	c := lookupCache.Do(lookupCacheKey{proxy, path}, func() any {
+		r := newCachingRepo(path, func() (Repo, error) {
+			r, err := lookup(proxy, path)
+			if err == nil && traceRepo {
+				r = newLoggingRepo(r)
+			}
+			return r, err
+		})
+		return cached{r}
+	}).(cached)
+
+	return c.r
+}
+
+// lookup returns the module with the given module path.
+func lookup(proxy, path string) (r Repo, err error) {
+	if cfg.BuildMod == "vendor" {
+		return nil, errLookupDisabled
+	}
+
+	if module.MatchPrefixPatterns(cfg.GONOPROXY, path) {
+		switch proxy {
+		case "noproxy", "direct":
+			return lookupDirect(path)
+		default:
+			return nil, errNoproxy
+		}
+	}
+
+	switch proxy {
+	case "off":
+		return errRepo{path, errProxyOff}, nil
+	case "direct":
+		return lookupDirect(path)
+	case "noproxy":
+		return nil, errUseProxy
+	default:
+		return newProxyRepo(proxy, path)
+	}
+}
+
+type lookupDisabledError struct{}
+
+func (lookupDisabledError) Error() string {
+	if cfg.BuildModReason == "" {
+		return fmt.Sprintf("module lookup disabled by -mod=%s", cfg.BuildMod)
+	}
+	return fmt.Sprintf("module lookup disabled by -mod=%s\n\t(%s)", cfg.BuildMod, cfg.BuildModReason)
+}
+
+var errLookupDisabled error = lookupDisabledError{}
+
+var (
+	errProxyOff       = notExistErrorf("module lookup disabled by GOPROXY=off")
+	errNoproxy  error = notExistErrorf("disabled by GOPRIVATE/GONOPROXY")
+	errUseProxy error = notExistErrorf("path does not match GOPRIVATE/GONOPROXY")
+)
+
+func lookupDirect(path string) (Repo, error) {
+	security := web.SecureOnly
+
+	if module.MatchPrefixPatterns(cfg.GOINSECURE, path) {
+		security = web.Insecure
+	}
+	rr, err := vcs.RepoRootForImportPath(path, vcs.PreferMod, security)
+	if err != nil {
+		// We don't know where to find code for a module with this path.
+		return nil, notExistError{err: err}
+	}
+
+	if rr.VCS.Name == "mod" {
+		// Fetch module from proxy with base URL rr.Repo.
+		return newProxyRepo(rr.Repo, path)
+	}
+
+	code, err := lookupCodeRepo(rr)
+	if err != nil {
+		return nil, err
+	}
+	return newCodeRepo(code, rr.Root, path)
+}
+
+func lookupCodeRepo(rr *vcs.RepoRoot) (codehost.Repo, error) {
+	code, err := codehost.NewRepo(rr.VCS.Cmd, rr.Repo)
+	if err != nil {
+		if _, ok := err.(*codehost.VCSError); ok {
+			return nil, err
+		}
+		return nil, fmt.Errorf("lookup %s: %v", rr.Root, err)
+	}
+	return code, nil
+}
+
+// A loggingRepo is a wrapper around an underlying Repo
+// that prints a log message at the start and end of each call.
+// It can be inserted when debugging.
+type loggingRepo struct {
+	r Repo
+}
+
+func newLoggingRepo(r Repo) *loggingRepo {
+	return &loggingRepo{r}
+}
+
+// logCall prints a log message using format and args and then
+// also returns a function that will print the same message again,
+// along with the elapsed time.
+// Typical usage is:
+//
+//	defer logCall("hello %s", arg)()
+//
+// Note the final ().
+func logCall(format string, args ...any) func() {
+	start := time.Now()
+	fmt.Fprintf(os.Stderr, "+++ %s\n", fmt.Sprintf(format, args...))
+	return func() {
+		fmt.Fprintf(os.Stderr, "%.3fs %s\n", time.Since(start).Seconds(), fmt.Sprintf(format, args...))
+	}
+}
+
+func (l *loggingRepo) ModulePath() string {
+	return l.r.ModulePath()
+}
+
+func (l *loggingRepo) CheckReuse(old *codehost.Origin) (err error) {
+	defer func() {
+		logCall("CheckReuse[%s]: %v", l.r.ModulePath(), err)
+	}()
+	return l.r.CheckReuse(old)
+}
+
+func (l *loggingRepo) Versions(prefix string) (*Versions, error) {
+	defer logCall("Repo[%s]: Versions(%q)", l.r.ModulePath(), prefix)()
+	return l.r.Versions(prefix)
+}
+
+func (l *loggingRepo) Stat(rev string) (*RevInfo, error) {
+	defer logCall("Repo[%s]: Stat(%q)", l.r.ModulePath(), rev)()
+	return l.r.Stat(rev)
+}
+
+func (l *loggingRepo) Latest() (*RevInfo, error) {
+	defer logCall("Repo[%s]: Latest()", l.r.ModulePath())()
+	return l.r.Latest()
+}
+
+func (l *loggingRepo) GoMod(version string) ([]byte, error) {
+	defer logCall("Repo[%s]: GoMod(%q)", l.r.ModulePath(), version)()
+	return l.r.GoMod(version)
+}
+
+func (l *loggingRepo) Zip(dst io.Writer, version string) error {
+	dstName := "_"
+	if dst, ok := dst.(interface{ Name() string }); ok {
+		dstName = strconv.Quote(dst.Name())
+	}
+	defer logCall("Repo[%s]: Zip(%s, %q)", l.r.ModulePath(), dstName, version)()
+	return l.r.Zip(dst, version)
+}
+
+// errRepo is a Repo that returns the same error for all operations.
+//
+// It is useful in conjunction with caching, since cache hits will not attempt
+// the prohibited operations.
+type errRepo struct {
+	modulePath string
+	err        error
+}
+
+func (r errRepo) ModulePath() string { return r.modulePath }
+
+func (r errRepo) CheckReuse(old *codehost.Origin) error     { return r.err }
+func (r errRepo) Versions(prefix string) (*Versions, error) { return nil, r.err }
+func (r errRepo) Stat(rev string) (*RevInfo, error)         { return nil, r.err }
+func (r errRepo) Latest() (*RevInfo, error)                 { return nil, r.err }
+func (r errRepo) GoMod(version string) ([]byte, error)      { return nil, r.err }
+func (r errRepo) Zip(dst io.Writer, version string) error   { return r.err }
+
+// A notExistError is like fs.ErrNotExist, but with a custom message
+type notExistError struct {
+	err error
+}
+
+func notExistErrorf(format string, args ...any) error {
+	return notExistError{fmt.Errorf(format, args...)}
+}
+
+func (e notExistError) Error() string {
+	return e.err.Error()
+}
+
+func (notExistError) Is(target error) bool {
+	return target == fs.ErrNotExist
+}
+
+func (e notExistError) Unwrap() error {
+	return e.err
+}