Unsafe defer of
.Close method GO-S2307Deferring unsafe method "Close" on type "*os.File"
79 if err != nil {
80 return err
81 }
82 defer f.Close()83
84 metadata := resp.AddOn.Metadata.(map[string]interface{})
85 kubeconfig := metadata["kubeconfig"].(string)Deferring unsafe method "Close" on type "*os.File"
52 if err != nil {
53 return err
54 }
55 defer f.Close()56
57 _, err = f.Write([]byte(kubeconfig))
58 if err != nil {Deferring unsafe method "Close" on type "*os.File"
174 if err != nil {
175 return err
176 }
177 defer f.Close()178
179 if _, err := io.WriteString(f, filePrepender(filename)); err != nil {
180 return errDeferring unsafe method "Close" on type "*os.File"
507 sc.out("get %s -> %s: %s", rpath, localFile, err)
508 return
509 }
510 defer f.Close()511
512 sc.out("get %s -> %s", rpath, localFile)
513Deferring unsafe method "Close" on type "*os.File"
316 sc.out("get %s -> %s: %s", rpath, lpath, err)
317 return
318 }
319 defer f.Close()320 z := zip.NewWriter(f)
321
322 defer z.Close()
Description
Calling Close() method may return an error, and ignoring the same
might result in a data loss. This is similar to many more Close methods.
For example, on POSIX systems, os.Close uses the close system call underneath,
which may return an EIO:
A previously-uncommitted write(2) encountered an input/output error.
This means that the data written by os.Write hasn't been written to the disk,
which results in a data loss. It is recommended to handle the error returned
by the os.Close call or call os.Sync if available to force the OS to write
the data to the disk.
Bad practice
package main
import (
"fmt"
"os"
)
func foo() error {
f, err := os.Create("/tmp/test.txt")
if err != nil {
return err
}
defer f.Close()
return fmt.Fprint(f, "Hello World")
}
Recommended
package main
import (
"fmt"
"os"
)
func foo() error {
f, err := os.Create("/tmp/test.txt")
if err != nil {
return err
}
err = fmt.Fprint(f, "Hello World")
if err != nil {
return err
}
return f.Close()
}
package main
import (
"fmt"
"os"
)
func foo() error {
f, err := os.Create("/tmp/test.txt")
if err != nil {
return err
}
defer f.Close()
err = fmt.Fprint(f, "Hello World")
if err != nil {
return err
}
return f.Sync()
}