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SelfDrivingCarpSelfDrivingCarp
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target: rework modtime comparison logic #323 (#324)
* target: rework modtime comparison logic * fix NewestModTime, add tests for NewestModTime, OldestModTime * added tests for Dir when target is Dir * updates per #324
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4 files changed

+264
-131
lines changed

4 files changed

+264
-131
lines changed

‎target/newer.go

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package target
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import (
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"fmt"
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"os"
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"path/filepath"
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"time"
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)
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var (
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// errNewer is an ugly sentinel error to cause filepath.Walk to abort
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// as soon as a newer file is encountered
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errNewer = fmt.Errorf("newer item encountered")
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)
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// DirNewer reports whether any item in sources is newer than the target time.
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// Sources are searched recursively and searching stops as soon as any entry
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// is newer than the target.
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func DirNewer(target time.Time, sources ...string) (bool, error) {
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walkFn := func(path string, info os.FileInfo, err error) error {
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if err != nil {
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return err
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}
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if info.ModTime().After(target) {
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return errNewer
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}
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return nil
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}
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for _, source := range sources {
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source = os.ExpandEnv(source)
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err := filepath.Walk(source, walkFn)
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if err == nil {
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continue
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}
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if err == errNewer {
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return true, nil
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}
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return false, err
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}
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return false, nil
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}
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// GlobNewer performs glob expansion on each source and passes the results to
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// PathNewer for inspection. It returns the first time PathNewer encounters a
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// newer file
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func GlobNewer(target time.Time, sources ...string) (bool, error) {
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for _, g := range sources {
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files, err := filepath.Glob(g)
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if err != nil {
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return false, err
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}
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if len(files) == 0 {
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return false, fmt.Errorf("glob didn't match any files: %s", g)
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}
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newer, err := PathNewer(target, files...)
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if err != nil {
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return false, err
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}
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if newer {
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return true, nil
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}
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}
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return false, nil
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}
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// PathNewer checks whether any of the sources are newer than the target time.
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// It stops at the first newer file it encounters. Each source path is passed
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// through os.ExpandEnv.
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func PathNewer(target time.Time, sources ...string) (bool, error) {
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for _, source := range sources {
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source = os.ExpandEnv(source)
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stat, err := os.Stat(source)
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if err != nil {
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return false, err
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}
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if stat.ModTime().After(target) {
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return true, nil
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}
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}
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return false, nil
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}
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// OldestModTime recurses a list of target filesystem objects and finds the
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// the oldest ModTime among them.
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func OldestModTime(targets ...string) (time.Time, error) {
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t := time.Now().Add(time.Hour * 100000)
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for _, target := range targets {
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walkFn := func(_ string, info os.FileInfo, err error) error {
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if err != nil {
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return err
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}
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mTime := info.ModTime()
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if mTime.Before(t) {
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t = mTime
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}
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return nil
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}
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if err := filepath.Walk(target, walkFn); err != nil {
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return t, err
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}
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}
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return t, nil
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}
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// NewestModTime recurses a list of target filesystem objects and finds the
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// the newest ModTime among them.
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func NewestModTime(targets ...string) (time.Time, error) {
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t := time.Time{}
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for _, target := range targets {
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walkFn := func(_ string, info os.FileInfo, err error) error {
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if err != nil {
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return err
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}
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mTime := info.ModTime()
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if mTime.After(t) {
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t = mTime
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}
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return nil
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}
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if err := filepath.Walk(target, walkFn); err != nil {
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return t, err
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}
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}
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return t, nil
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}

‎target/newer_test.go

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package target
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import (
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"io/ioutil"
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"os"
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"path/filepath"
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"testing"
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"time"
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)
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func TestNewestModTime(t *testing.T) {
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t.Parallel()
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dir, err := ioutil.TempDir("", "")
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if err != nil {
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t.Fatalf("error creating temp dir: %s", err.Error())
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}
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defer os.RemoveAll(dir)
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for _, name := range []string{"a", "b", "c", "d"} {
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out := filepath.Join(dir, name)
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if err := ioutil.WriteFile(out, []byte("hi!"), 0644); err != nil {
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t.Fatalf("error writing file: %s", err.Error())
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}
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}
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time.Sleep(10 * time.Millisecond)
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outName := filepath.Join(dir, "c")
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outfh, err := os.OpenFile(outName, os.O_APPEND|os.O_WRONLY, 0644)
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if err != nil {
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t.Fatalf("error opening file to append: %s", err.Error())
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}
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if _, err := outfh.WriteString("\nbye!\n"); err != nil {
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t.Fatalf("error appending to file: %s", err.Error())
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}
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if err := outfh.Close(); err != nil {
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t.Fatalf("error closing file: %s", err.Error())
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}
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afi, err := os.Stat(filepath.Join(dir, "a"))
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if err != nil {
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t.Fatalf("error stating unmodified file: %s", err.Error())
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}
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cfi, err := os.Stat(outName)
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if err != nil {
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t.Fatalf("error stating modified file: %s", err.Error())
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}
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if afi.ModTime().Equal(cfi.ModTime()) {
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t.Fatal("modified and unmodified file mtimes equal")
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}
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newest, err := NewestModTime(dir)
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if err != nil {
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t.Fatalf("error finding newest mod time: %s", err.Error())
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}
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if !newest.Equal(cfi.ModTime()) {
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t.Fatal("expected newest mod time to match c")
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}
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}
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func TestOldestModTime(t *testing.T) {
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t.Parallel()
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dir, err := ioutil.TempDir("", "")
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if err != nil {
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t.Fatalf("error creating temp dir: %s", err.Error())
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}
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defer os.RemoveAll(dir)
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for _, name := range []string{"a", "b", "c", "d"} {
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out := filepath.Join(dir, name)
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if err := ioutil.WriteFile(out, []byte("hi!"), 0644); err != nil {
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t.Fatalf("error writing file: %s", err.Error())
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}
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}
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time.Sleep(10 * time.Millisecond)
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for _, name := range []string{"a", "b", "d"} {
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outName := filepath.Join(dir, name)
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outfh, err := os.OpenFile(outName, os.O_APPEND|os.O_WRONLY, 0644)
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if err != nil {
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t.Fatalf("error opening file to append: %s", err.Error())
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}
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if _, err := outfh.WriteString("\nbye!\n"); err != nil {
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t.Fatalf("error appending to file: %s", err.Error())
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}
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if err := outfh.Close(); err != nil {
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t.Fatalf("error closing file: %s", err.Error())
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}
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}
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afi, err := os.Stat(filepath.Join(dir, "a"))
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if err != nil {
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t.Fatalf("error stating unmodified file: %s", err.Error())
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}
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outName := filepath.Join(dir, "c")
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cfi, err := os.Stat(outName)
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if err != nil {
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t.Fatalf("error stating modified file: %s", err.Error())
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}
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if afi.ModTime().Equal(cfi.ModTime()) {
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t.Fatal("modified and unmodified file mtimes equal")
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}
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newest, err := OldestModTime(dir)
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if err != nil {
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t.Fatalf("error finding oldest mod time: %s", err.Error())
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}
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if !newest.Equal(cfi.ModTime()) {
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t.Fatal("expected newest mod time to match c")
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}
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}

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