Kill background fetch when it requests a passphrase (#4588)

Previously we would enter a newline at the password prompt, which would
cause the fetch to fail. The problem with this was that if you have many
remotes, the fetch would sometimes hang for some reason; I don't totally
understand how that happened, but I guess the many ssh processes
requesting passwords would somehow interfere with each other. Avoid this
by simply killing the git fetch process the moment it requests the first
password.

Author: stefanhaller

pkg/commands/oscommands/cmd_obj_runner.go

@@ -10,7 +10,6 @@ import (
 	"time"
 
 	"github.com/go-errors/errors"
-	"github.com/jesseduffield/gocui"
 	"github.com/jesseduffield/lazygit/pkg/utils"
 	"github.com/sasha-s/go-deadlock"
 	"github.com/sirupsen/logrus"
@@ -295,14 +294,10 @@ const (
 	Token
 )
 
-// Whenever we're asked for a password we just enter a newline, which will
-// eventually cause the command to fail.
+// Whenever we're asked for a password we return a nil channel to tell the
+// caller to kill the process.
 var failPromptFn = func(CredentialType) <-chan string {
-	ch := make(chan string)
-	go func() {
-		ch <- "\n"
-	}()
-	return ch
+	return nil
 }
 
 func (self *cmdObjRunner) runWithCredentialHandling(cmdObj *CmdObj) error {
@@ -340,7 +335,7 @@ func (self *cmdObjRunner) runAndDetectCredentialRequest(
 		tr := io.TeeReader(handler.stdoutPipe, cmdWriter)
 
 		go utils.Safe(func() {
-			self.processOutput(tr, handler.stdinPipe, promptUserForCredential, cmdObj.GetTask())
+			self.processOutput(tr, handler.stdinPipe, promptUserForCredential, cmdObj)
 		})
 	})
 }
@@ -349,9 +344,10 @@ func (self *cmdObjRunner) processOutput(
 	reader io.Reader,
 	writer io.Writer,
 	promptUserForCredential func(CredentialType) <-chan string,
-	task gocui.Task,
+	cmdObj *CmdObj,
 ) {
 	checkForCredentialRequest := self.getCheckForCredentialRequestFunc()
+	task := cmdObj.GetTask()
 
 	scanner := bufio.NewScanner(reader)
 	scanner.Split(bufio.ScanBytes)
@@ -360,16 +356,26 @@ func (self *cmdObjRunner) processOutput(
 		askFor, ok := checkForCredentialRequest(newBytes)
 		if ok {
 			responseChan := promptUserForCredential(askFor)
-			if task != nil {
-				task.Pause()
-			}
-			toInput := <-responseChan
-			if task != nil {
-				task.Continue()
-			}
-			// If the return data is empty we don't write anything to stdin
-			if toInput != "" {
-				_, _ = writer.Write([]byte(toInput))
+			if responseChan == nil {
+				// Returning a nil channel means we should kill the process.
+				// Note that we don't break the loop after this, because we
+				// still need to drain the output, otherwise the Wait() call
+				// later might block.
+				if err := Kill(cmdObj.GetCmd()); err != nil {
+					self.log.Error(err)
+				}
+			} else {
+				if task != nil {
+					task.Pause()
+				}
+				toInput := <-responseChan
+				if task != nil {
+					task.Continue()
+				}
+				// If the return data is empty we don't write anything to stdin
+				if toInput != "" {
+					_, _ = writer.Write([]byte(toInput))
+				}
 			}
 		}
 	}

pkg/commands/oscommands/cmd_obj_runner_test.go

@@ -120,8 +120,8 @@ func TestProcessOutput(t *testing.T) {
 			reader := strings.NewReader(scenario.output)
 			writer := &strings.Builder{}
 
-			task := gocui.NewFakeTask()
-			runner.processOutput(reader, writer, toChanFn(scenario.promptUserForCredential), task)
+			cmdObj := &CmdObj{task: gocui.NewFakeTask()}
+			runner.processOutput(reader, writer, toChanFn(scenario.promptUserForCredential), cmdObj)
 
 			if writer.String() != scenario.expectedToWrite {
 				t.Errorf("expected to write '%s' but got '%s'", scenario.expectedToWrite, writer.String())