improve fprintf related error handling

cmd/restic/cmd_backup_integration_test.go

@@ -351,12 +351,7 @@ func TestBackupExclude(t *testing.T) {
 	for _, filename := range backupExcludeFilenames {
 		fp := filepath.Join(datadir, filename)
 		rtest.OK(t, os.MkdirAll(filepath.Dir(fp), 0755))
-
+		rtest.OK(t, os.WriteFile(fp, []byte(filename), 0o666))
-		f, err := os.Create(fp)
-		rtest.OK(t, err)
-
-		fmt.Fprint(f, filename)
-		rtest.OK(t, f.Close())
 	}
 
 	snapshots := make(map[string]struct{})

cmd/restic/cmd_backup_test.go

@@ -39,21 +39,24 @@ func TestCollectTargets(t *testing.T) {
 	f1, err := os.Create(filepath.Join(dir, "fromfile"))
 	rtest.OK(t, err)
 	// Empty lines should be ignored. A line starting with '#' is a comment.
-	fmt.Fprintf(f1, "\n%s*\n # here's a comment\n", f1.Name())
+	_, err = fmt.Fprintf(f1, "\n%s*\n # here's a comment\n", f1.Name())
+	rtest.OK(t, err)
 	rtest.OK(t, f1.Close())
 
 	f2, err := os.Create(filepath.Join(dir, "fromfile-verbatim"))
 	rtest.OK(t, err)
 	for _, filename := range []string{fooSpace, barStar} {
 		// Empty lines should be ignored. CR+LF is allowed.
-		fmt.Fprintf(f2, "%s\r\n\n", filepath.Join(dir, filename))
+		_, err = fmt.Fprintf(f2, "%s\r\n\n", filepath.Join(dir, filename))
+		rtest.OK(t, err)
 	}
 	rtest.OK(t, f2.Close())
 
 	f3, err := os.Create(filepath.Join(dir, "fromfile-raw"))
 	rtest.OK(t, err)
 	for _, filename := range []string{"baz", "quux"} {
-		fmt.Fprintf(f3, "%s\x00", filepath.Join(dir, filename))
+		_, err = fmt.Fprintf(f3, "%s\x00", filepath.Join(dir, filename))
+		rtest.OK(t, err)
 	}
 	rtest.OK(t, err)
 	rtest.OK(t, f3.Close())

cmd/restic/cmd_snapshots.go

@@ -296,7 +296,9 @@ func PrintSnapshotGroupHeader(stdout io.Writer, groupKeyJSON string) error {
 	}
 
 	// Info
-	fmt.Fprintf(stdout, "snapshots")
+	if _, err := fmt.Fprintf(stdout, "snapshots"); err != nil {
+		return err
+	}
 	var infoStrings []string
 	if key.Hostname != "" {
 		infoStrings = append(infoStrings, "host ["+key.Hostname+"]")
@@ -308,11 +310,13 @@ func PrintSnapshotGroupHeader(stdout io.Writer, groupKeyJSON string) error {
 		infoStrings = append(infoStrings, "paths ["+strings.Join(key.Paths, ", ")+"]")
 	}
 	if infoStrings != nil {
-		fmt.Fprintf(stdout, " for (%s)", strings.Join(infoStrings, ", "))
+		if _, err := fmt.Fprintf(stdout, " for (%s)", strings.Join(infoStrings, ", ")); err != nil {
+			return err
+		}
 	}
-	fmt.Fprintf(stdout, ":\n")
+	_, err = fmt.Fprintf(stdout, ":\n")
 
-	return nil
+	return err
 }
 
 // Snapshot helps to print Snapshots as JSON with their ID included.

cmd/restic/global.go

@@ -308,7 +308,7 @@ func readPasswordTerminal(ctx context.Context, in *os.File, out *os.File, prompt
 	fd := int(out.Fd())
 	state, err := term.GetState(fd)
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "unable to get terminal state: %v\n", err)
+		_, _ = fmt.Fprintf(os.Stderr, "unable to get terminal state: %v\n", err)
 		return "", err
 	}
 
@@ -317,16 +317,22 @@ func readPasswordTerminal(ctx context.Context, in *os.File, out *os.File, prompt
 
 	go func() {
 		defer close(done)
-		fmt.Fprint(out, prompt)
+		_, err = fmt.Fprint(out, prompt)
+		if err != nil {
+			return
+		}
 		buf, err = term.ReadPassword(int(in.Fd()))
-		fmt.Fprintln(out)
+		if err != nil {
+			return
+		}
+		_, err = fmt.Fprintln(out)
 	}()
 
 	select {
 	case <-ctx.Done():
 		err := term.Restore(fd, state)
 		if err != nil {
-			fmt.Fprintf(os.Stderr, "unable to restore terminal state: %v\n", err)
+			_, _ = fmt.Fprintf(os.Stderr, "unable to restore terminal state: %v\n", err)
 		}
 		return "", ctx.Err()
 	case <-done:

cmd/restic/integration_helpers_unix_test.go

@@ -13,17 +13,17 @@ import (
 
 func (e *dirEntry) equals(out io.Writer, other *dirEntry) bool {
 	if e.path != other.path {
-		fmt.Fprintf(out, "%v: path does not match (%v != %v)\n", e.path, e.path, other.path)
+		_, _ = fmt.Fprintf(out, "%v: path does not match (%v != %v)\n", e.path, e.path, other.path)
 		return false
 	}
 
 	if e.fi.Mode() != other.fi.Mode() {
-		fmt.Fprintf(out, "%v: mode does not match (%v != %v)\n", e.path, e.fi.Mode(), other.fi.Mode())
+		_, _ = fmt.Fprintf(out, "%v: mode does not match (%v != %v)\n", e.path, e.fi.Mode(), other.fi.Mode())
 		return false
 	}
 
 	if !sameModTime(e.fi, other.fi) {
-		fmt.Fprintf(out, "%v: ModTime does not match (%v != %v)\n", e.path, e.fi.ModTime(), other.fi.ModTime())
+		_, _ = fmt.Fprintf(out, "%v: ModTime does not match (%v != %v)\n", e.path, e.fi.ModTime(), other.fi.ModTime())
 		return false
 	}
 
@@ -31,17 +31,17 @@ func (e *dirEntry) equals(out io.Writer, other *dirEntry) bool {
 	stat2, _ := other.fi.Sys().(*syscall.Stat_t)
 
 	if stat.Uid != stat2.Uid {
-		fmt.Fprintf(out, "%v: UID does not match (%v != %v)\n", e.path, stat.Uid, stat2.Uid)
+		_, _ = fmt.Fprintf(out, "%v: UID does not match (%v != %v)\n", e.path, stat.Uid, stat2.Uid)
 		return false
 	}
 
 	if stat.Gid != stat2.Gid {
-		fmt.Fprintf(out, "%v: GID does not match (%v != %v)\n", e.path, stat.Gid, stat2.Gid)
+		_, _ = fmt.Fprintf(out, "%v: GID does not match (%v != %v)\n", e.path, stat.Gid, stat2.Gid)
 		return false
 	}
 
 	if stat.Nlink != stat2.Nlink {
-		fmt.Fprintf(out, "%v: Number of links do not match (%v != %v)\n", e.path, stat.Nlink, stat2.Nlink)
+		_, _ = fmt.Fprintf(out, "%v: Number of links do not match (%v != %v)\n", e.path, stat.Nlink, stat2.Nlink)
 		return false
 	}
 

cmd/restic/main.go

@@ -140,7 +140,7 @@ func printExitError(code int, message string) {
 			return
 		}
 	} else {
-		fmt.Fprintf(globalOptions.stderr, "%v\n", message)
+		_, _ = fmt.Fprintf(globalOptions.stderr, "%v\n", message)
 	}
 }
 
@@ -152,10 +152,10 @@ func main() {
 	log.SetOutput(logBuffer)
 
 	err := feature.Flag.Apply(os.Getenv("RESTIC_FEATURES"), func(s string) {
-		fmt.Fprintln(os.Stderr, s)
+		_, _ = fmt.Fprintln(os.Stderr, s)
 	})
 	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
+		_, _ = fmt.Fprintln(os.Stderr, err)
 		Exit(1)
 	}
 

internal/backend/rest/rest_test.go

@@ -106,7 +106,7 @@ func runRESTServer(ctx context.Context, t testing.TB, dir, reqListenAddr string)
 					matched = true
 				}
 			}
-			fmt.Fprintln(os.Stdout, line) // print all output to console
+			_, _ = fmt.Fprintln(os.Stdout, line) // print all output to console
 		}
 	}()
 

internal/debug/debug.go

@@ -120,7 +120,7 @@ func goroutineNum() int {
 	runtime.Stack(b, false)
 	var num int
 
-	fmt.Sscanf(string(b), "goroutine %d ", &num)
+	_, _ = fmt.Sscanf(string(b), "goroutine %d ", &num)
 	return num
 }
 

internal/debug/round_tripper.go

@@ -42,7 +42,7 @@ func (rd *eofDetectReader) Close() error {
 			msg += fmt.Sprintf(", body: %q", buf)
 		}
 
-		fmt.Fprintln(os.Stderr, msg)
+		_, _ = fmt.Fprintln(os.Stderr, msg)
 		Log("%s: %+v", msg, errors.New("Close()"))
 	}
 	return rd.rd.Close()

internal/ui/termstatus/status.go

@@ -212,7 +212,7 @@ func (t *Terminal) runWithoutStatus(ctx context.Context) {
 			}
 
 			if _, err := io.WriteString(dst, msg.line); err != nil {
-				fmt.Fprintf(os.Stderr, "write failed: %v\n", err)
+				_, _ = fmt.Fprintf(os.Stderr, "write failed: %v\n", err)
 			}
 
 			if flush == nil {
@@ -220,16 +220,18 @@ func (t *Terminal) runWithoutStatus(ctx context.Context) {
 			}
 
 			if err := flush(); err != nil {
-				fmt.Fprintf(os.Stderr, "flush failed: %v\n", err)
+				_, _ = fmt.Fprintf(os.Stderr, "flush failed: %v\n", err)
 			}
 
 		case stat := <-t.status:
 			for _, line := range stat.lines {
 				// Ensure that each message ends with exactly one newline.
-				fmt.Fprintln(t.wr, strings.TrimRight(line, "\n"))
+				if _, err := fmt.Fprintln(t.wr, strings.TrimRight(line, "\n")); err != nil {
+					_, _ = fmt.Fprintf(os.Stderr, "write failed: %v\n", err)
+				}
 			}
 			if err := t.wr.Flush(); err != nil {
-				fmt.Fprintf(os.Stderr, "flush failed: %v\n", err)
+				_, _ = fmt.Fprintf(os.Stderr, "flush failed: %v\n", err)
 			}
 		}
 	}