Merge pull request #215 from walles/johan/reprint-after-close-stdin

Fix crash on --quit-if-one-screen by dupping stdout

moar.go

@@ -279,6 +279,7 @@ func printProblemsHeader() {
  fmt.Fprintln(os.Stderr, "Version:", versionString)
  fmt.Fprintln(os.Stderr, "LANG :", os.Getenv("LANG"))
  fmt.Fprintln(os.Stderr, "TERM :", os.Getenv("TERM"))
+ fmt.Fprintln(os.Stderr, "MOAR :", os.Getenv("MOAR"))
  fmt.Fprintln(os.Stderr)
  fmt.Fprintln(os.Stderr, "GOOS :", runtime.GOOS)
  fmt.Fprintln(os.Stderr, "GOARCH :", runtime.GOARCH)

test.sh

@@ -77,6 +77,13 @@ echo Testing not crashing with different argument orders...
 ./moar --trace +123 moar.go >/dev/null
 ./moar --trace moar.go +123 >/dev/null
 
+# We can only do this test if we have a terminal. This means it will be run
+# locally but not in CI. Not great, but better than nothing.
+if [[ -t 1 ]]; then
+ echo Test auto quitting on single screen...
+ echo " (success)" | ./moar --quit-if-one-screen
+fi
+
 echo Test decompressing while piping
 # Related to https://github.com/walles/moar/issues/177
 ./moar sample-files/compressed.txt.gz | grep compressed >/dev/null

twin/screen-setup.go

@@ -45,18 +45,27 @@ func (screen *UnixScreen) setupSigwinchNotification() {
 }
 
 func (screen *UnixScreen) setupTtyInTtyOut() error {
+ // Dup stdout so we can close stdin in Close() without closing stdout.
+ // Before this dupping, we crashed on using --quit-if-one-screen.
+ //
+ // Ref:https://github.com/walles/moar/issues/214
+ stdoutDupFd, err := syscall.Dup(int(os.Stdout.Fd()))
+ if err != nil {
+ return err
+ }
+ stdoutDup := os.NewFile(uintptr(stdoutDupFd), "moar-stdout-dup")
+
  // os.Stdout is a stream that goes to our terminal window.
  //
  // So if we read from there, we'll get input from the terminal window.
  //
- // Reading from os.Stdin will fail if we're getting data piped into
- // ourselves from some other command.
+ // If we just read from os.Stdin that would fail if we're getting data piped
+ // into ourselves from some other command.
  //
  // Tested on macOS and Linux, works like a charm!
- screen.ttyIn = os.Stdout // <- YES, WE SHOULD ASSIGN STDOUT TO TTYIN
+ screen.ttyIn = stdoutDup // <- YES, WE SHOULD ASSIGN STDOUT TO TTYIN
 
  // Set input stream to raw mode
- var err error
  screen.oldTerminalState, err = term.MakeRaw(int(screen.ttyIn.Fd()))
  if err != nil {
  return err