main.go: remove file if on Flatten(..) failure
When a Flatten() fails, the main program used to leave an incomplete file (usually zero-length). Now it will clean itself up on failure.
This commit is contained in:
parent
6f40bc91be
commit
4568429a69
16
main.go
16
main.go
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@ -53,15 +53,15 @@ type command struct {
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Stdout io.Writer
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}
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func (c *command) execute(infile string, outfile string) (err error) {
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func (c *command) execute(infile string, outfile string) (_err error) {
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rd, err := os.Open(infile)
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if err != nil {
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return err
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}
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defer func() {
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err1 := rd.Close()
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if err == nil {
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err = err1
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err := rd.Close()
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if _err == nil {
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_err = err
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}
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}()
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@ -74,9 +74,11 @@ func (c *command) execute(infile string, outfile string) (err error) {
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return fmt.Errorf("create: %w", err)
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}
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defer func() {
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err1 := outf.Close()
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if err == nil {
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err = err1
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err := outf.Close()
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if _err != nil {
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os.Remove(outfile)
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} else {
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_err = err
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}
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}()
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out = outf
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60
main_test.go
60
main_test.go
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@ -2,8 +2,10 @@ package main
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import (
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"bytes"
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"errors"
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"io"
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"io/ioutil"
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"os"
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"path/filepath"
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"regexp"
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"testing"
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@ -13,11 +15,13 @@ func TestExecute(t *testing.T) {
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var _foo = []byte("foo foo")
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tests := []struct {
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name string
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fixture func(*testing.T, string)
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infile string
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outfile string
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wantErr string
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name string
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fixture func(*testing.T, string)
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flattener func(io.ReadSeeker, io.Writer) error
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infile string
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outfile string
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wantErr string
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assertion func(*testing.T, string)
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}{
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{
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name: "ok passthrough via stdout",
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@ -41,6 +45,31 @@ func TestExecute(t *testing.T) {
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},
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outfile: "t20-out.txt",
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},
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{
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name: "bad flattener should remove the file",
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infile: "t30-in.txt",
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fixture: func(t *testing.T, dir string) {
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fname := filepath.Join(dir, "t30-in.txt")
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if err := ioutil.WriteFile(fname, _foo, 0644); err != nil {
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t.Fatalf("unexpected error: %v", err)
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}
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},
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flattener: flattenBad,
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outfile: "t30-out.txt",
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wantErr: "some error",
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assertion: func(t *testing.T, dir string) {
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d, err := os.ReadDir(dir)
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if err != nil {
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t.Fatalf("unexpected error: %v", err)
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}
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if len(d) != 1 {
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t.Fatalf("expected 1 entry, got %d", len(d))
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}
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if d[0].Name() != "t30-in.txt" {
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t.Fatalf("expected to find only t30-in.txt, got %s", d[0].Name())
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}
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},
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},
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{
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name: "infile does not exist",
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infile: "t3-does-not-exist.txt",
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@ -57,7 +86,10 @@ func TestExecute(t *testing.T) {
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t.Run(tt.name, func(t *testing.T) {
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dir := t.TempDir()
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var stdout bytes.Buffer
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c := &command{Stdout: &stdout}
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if tt.flattener == nil {
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tt.flattener = flattenPassthrough
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}
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if tt.fixture != nil {
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tt.fixture(t, dir)
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}
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@ -65,9 +97,14 @@ func TestExecute(t *testing.T) {
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tt.outfile = filepath.Join(dir, tt.outfile)
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}
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inf := filepath.Join(dir, tt.infile)
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c.flattener = flattenPassthrough
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c := &command{Stdout: &stdout, flattener: tt.flattener}
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err := c.execute(inf, tt.outfile)
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if tt.assertion != nil {
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tt.assertion(t, dir)
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}
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if tt.wantErr != "" {
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if err == nil {
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t.Fatal("expected error, got nil")
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@ -78,10 +115,10 @@ func TestExecute(t *testing.T) {
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}
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return
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}
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var out []byte
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if err != nil {
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t.Fatalf("unexpected error: %v", err)
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}
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var out []byte
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if tt.outfile == "-" {
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out = stdout.Bytes()
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} else {
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@ -91,8 +128,9 @@ func TestExecute(t *testing.T) {
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}
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}
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if !bytes.Equal([]byte("foo foo"), out) {
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t.Errorf("out != foo foo: %s", string(out))
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t.Errorf("out != foo foo: %q", string(out))
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}
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})
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}
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}
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@ -101,3 +139,7 @@ func flattenPassthrough(r io.ReadSeeker, w io.Writer) error {
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_, err := io.Copy(w, r)
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return err
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}
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func flattenBad(_ io.ReadSeeker, _ io.Writer) error {
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return errors.New("some error")
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}
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