import (
"bytes"
+ "errors"
"fmt"
"io/ioutil"
"os"
_, zipErr = os.Stat(zip)
}
dir, dirErr := modfetch.DownloadDir(mod)
- if dirErr == nil {
- _, dirErr = os.Stat(dir)
- }
data, err := ioutil.ReadFile(zip + "hash")
if err != nil {
- if zipErr != nil && os.IsNotExist(zipErr) && dirErr != nil && os.IsNotExist(dirErr) {
+ if zipErr != nil && errors.Is(zipErr, os.ErrNotExist) &&
+ dirErr != nil && errors.Is(dirErr, os.ErrNotExist) {
// Nothing downloaded yet. Nothing to verify.
return true
}
}
h := string(bytes.TrimSpace(data))
- if zipErr != nil && os.IsNotExist(zipErr) {
+ if zipErr != nil && errors.Is(zipErr, os.ErrNotExist) {
// ok
} else {
hZ, err := dirhash.HashZip(zip, dirhash.DefaultHash)
ok = false
}
}
- if dirErr != nil && os.IsNotExist(dirErr) {
+ if dirErr != nil && errors.Is(dirErr, os.ErrNotExist) {
// ok
} else {
hD, err := dirhash.HashDir(dir, mod.Path+"@"+mod.Version, dirhash.DefaultHash)
import (
"bytes"
"encoding/json"
+ "errors"
"fmt"
"io"
"io/ioutil"
return filepath.Join(dir, encVer+"."+suffix), nil
}
-// DownloadDir returns the directory to which m should be downloaded.
-// Note that the directory may not yet exist.
+// DownloadDir returns the directory to which m should have been downloaded.
+// An error will be returned if the module path or version cannot be escaped.
+// An error satisfying errors.Is(err, os.ErrNotExist) will be returned
+// along with the directory if the directory does not exist or if the directory
+// is not completely populated.
func DownloadDir(m module.Version) (string, error) {
if PkgMod == "" {
return "", fmt.Errorf("internal error: modfetch.PkgMod not set")
if err != nil {
return "", err
}
- return filepath.Join(PkgMod, enc+"@"+encVer), nil
+
+ dir := filepath.Join(PkgMod, enc+"@"+encVer)
+ if fi, err := os.Stat(dir); os.IsNotExist(err) {
+ return dir, err
+ } else if err != nil {
+ return dir, &DownloadDirPartialError{dir, err}
+ } else if !fi.IsDir() {
+ return dir, &DownloadDirPartialError{dir, errors.New("not a directory")}
+ }
+ partialPath, err := CachePath(m, "partial")
+ if err != nil {
+ return dir, err
+ }
+ if _, err := os.Stat(partialPath); err == nil {
+ return dir, &DownloadDirPartialError{dir, errors.New("not completely extracted")}
+ } else if !os.IsNotExist(err) {
+ return dir, err
+ }
+ return dir, nil
+}
+
+// DownloadDirPartialError is returned by DownloadDir if a module directory
+// exists but was not completely populated.
+//
+// DownloadDirPartialError is equivalent to os.ErrNotExist.
+type DownloadDirPartialError struct {
+ Dir string
+ Err error
}
+func (e *DownloadDirPartialError) Error() string { return fmt.Sprintf("%s: %v", e.Dir, e.Err) }
+func (e *DownloadDirPartialError) Is(err error) bool { return err == os.ErrNotExist }
+
// lockVersion locks a file within the module cache that guards the downloading
// and extraction of the zipfile for the given module version.
func lockVersion(mod module.Version) (unlock func(), err error) {
err error
}
c := downloadCache.Do(mod, func() interface{} {
- dir, err := DownloadDir(mod)
+ dir, err := download(mod)
if err != nil {
return cached{"", err}
}
- if err := download(mod, dir); err != nil {
- return cached{"", err}
- }
checkMod(mod)
return cached{dir, nil}
}).(cached)
return c.dir, c.err
}
-func download(mod module.Version, dir string) (err error) {
- // If the directory exists, the module has already been extracted.
- fi, err := os.Stat(dir)
- if err == nil && fi.IsDir() {
- return nil
+func download(mod module.Version) (dir string, err error) {
+ // If the directory exists, and no .partial file exists,
+ // the module has already been completely extracted.
+ // .partial files may be created when future versions of cmd/go
+ // extract module zip directories in place instead of extracting
+ // to a random temporary directory and renaming.
+ dir, err = DownloadDir(mod)
+ if err == nil {
+ return dir, nil
+ } else if dir == "" || !errors.Is(err, os.ErrNotExist) {
+ return "", err
}
// To avoid cluttering the cache with extraneous files,
// Invoke DownloadZip before locking the file.
zipfile, err := DownloadZip(mod)
if err != nil {
- return err
+ return "", err
}
unlock, err := lockVersion(mod)
if err != nil {
- return err
+ return "", err
}
defer unlock()
// Check whether the directory was populated while we were waiting on the lock.
- fi, err = os.Stat(dir)
- if err == nil && fi.IsDir() {
- return nil
+ _, dirErr := DownloadDir(mod)
+ if dirErr == nil {
+ return dir, nil
}
+ _, dirExists := dirErr.(*DownloadDirPartialError)
- // Clean up any remaining temporary directories from previous runs.
+ // Clean up any remaining temporary directories from previous runs, as well
+ // as partially extracted diectories created by future versions of cmd/go.
// This is only safe to do because the lock file ensures that their writers
// are no longer active.
parentDir := filepath.Dir(dir)
RemoveAll(path) // best effort
}
}
+ if dirExists {
+ if err := RemoveAll(dir); err != nil {
+ return "", err
+ }
+ }
+
+ partialPath, err := CachePath(mod, "partial")
+ if err != nil {
+ return "", err
+ }
+ if err := os.Remove(partialPath); err != nil && !os.IsNotExist(err) {
+ return "", err
+ }
// Extract the zip file to a temporary directory, then rename it to the
// final path. That way, we can use the existence of the source directory to
// open files in the temporary directory (antivirus, search indexers, etc.)
// can cause os.Rename to fail with ERROR_ACCESS_DENIED.
if err := os.MkdirAll(parentDir, 0777); err != nil {
- return err
+ return "", err
}
tmpDir, err := ioutil.TempDir(parentDir, tmpPrefix)
if err != nil {
- return err
+ return "", err
}
defer func() {
if err != nil {
if err := modzip.Unzip(tmpDir, mod, zipfile); err != nil {
fmt.Fprintf(os.Stderr, "-> %s\n", err)
- return err
+ return "", err
}
if err := robustio.Rename(tmpDir, dir); err != nil {
- return err
+ return "", err
}
if !cfg.ModCacheRW {
// os.Rename was observed to fail for read-only directories on macOS.
makeDirsReadOnly(dir)
}
- return nil
+ return dir, nil
}
var downloadZipCache par.Cache
}
dir, err := modfetch.DownloadDir(mod)
if err == nil {
- if info, err := os.Stat(dir); err == nil && info.IsDir() {
- m.Dir = dir
- }
+ m.Dir = dir
}
}
}
"time"
)
-const arbitraryTimeout = 500 * time.Millisecond
+const arbitraryTimeout = 2000 * time.Millisecond
// retry retries ephemeral errors from f up to an arbitrary timeout
// to work around filesystem flakiness on Windows and Darwin.
--- /dev/null
+# Download a module
+go mod download -modcacherw rsc.io/quote
+exists $GOPATH/pkg/mod/rsc.io/quote@v1.5.2/go.mod
+
+# 'go mod verify' should fail if we delete a file.
+go mod verify
+rm $GOPATH/pkg/mod/rsc.io/quote@v1.5.2/go.mod
+! go mod verify
+
+# Create a .partial file to simulate an failure extracting the zip file.
+cp empty $GOPATH/pkg/mod/cache/download/rsc.io/quote/@v/v1.5.2.partial
+
+# 'go mod verify' should not fail, since the module hasn't been completely
+# ingested into the cache.
+go mod verify
+
+# 'go list' should not load packages from the directory.
+# NOTE: the message "directory $dir outside available modules" is reported
+# for directories not in the main module, active modules in the module cache,
+# or local replacements. In this case, the directory is in the right place,
+# but it's incomplete, so 'go list' acts as if it's not an active module.
+! go list $GOPATH/pkg/mod/rsc.io/quote@v1.5.2
+stderr 'outside available modules'
+
+# 'go list -m' should not print the directory.
+go list -m -f '{{.Dir}}' rsc.io/quote
+! stdout .
+
+# 'go mod download' should re-extract the module and remove the .partial file.
+go mod download -modcacherw rsc.io/quote
+! exists $GOPATH/pkg/mod/cache/download/rsc.io/quote/@v/v1.5.2.partial
+exists $GOPATH/pkg/mod/rsc.io/quote@v1.5.2/go.mod
+
+# 'go list' should succeed.
+go list $GOPATH/pkg/mod/rsc.io/quote@v1.5.2
+stdout '^rsc.io/quote$'
+
+# 'go list -m' should print the directory.
+go list -m -f '{{.Dir}}' rsc.io/quote
+stdout 'pkg[/\\]mod[/\\]rsc.io[/\\]quote@v1.5.2'
+
+# go mod verify should fail if we delete a file.
+go mod verify
+rm $GOPATH/pkg/mod/rsc.io/quote@v1.5.2/go.mod
+! go mod verify
+
+-- go.mod --
+module m
+
+go 1.14
+
+require rsc.io/quote v1.5.2
+
+-- empty --