Unsafe defer of
.Close method GO-S2307Deferring unsafe method "Close" on type "*os.File"
298 file.Close()
299 os.Exit(1)
300 } else {
301 defer file.Close()302 if err := scanner.SaveAs(file, res); err != nil {
303 log.Warn(err)
304 os.Exit(1)Deferring unsafe method "Close" on type "*os.File"
85 if err != nil {
86 return "", err
87 }
88 defer file.Close() 89
90 fileInfo, err := os.Stat(filepath)
91 if err != nil {Deferring unsafe method "Close" on type "*os.File"
280 file.Close()
281 os.Exit(1)
282 } else {
283 defer file.Close()284 if err := scanner.Output(file, res); err != nil {
285 log.Warn(err)
286 os.Exit(1)Deferring unsafe method "Close" on type "*os.File"
317 file.Close()
318 os.Exit(1)
319 } else {
320 defer file.Close()321 if _, err := file.WriteString(hexStr); err != nil {
322 log.Warn(err)
323 os.Exit(1)
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()
}