Check that input is a tty before using it

cmd/limactl/clone.go

@@ -121,7 +121,7 @@ func cloneOrRenameAction(cmd *cobra.Command, args []string) error {
 	}
 
 	if tty && !flags.Changed("start") {
-		start, err = askWhetherToStart()
+		start, err = askWhetherToStart(cmd)
 		if err != nil {
 			return err
 		}

cmd/limactl/edit.go

@@ -153,7 +153,7 @@ func editAction(cmd *cobra.Command, args []string) error {
 	}
 
 	if tty && !flags.Changed("start") {
-		start, err = askWhetherToStart()
+		start, err = askWhetherToStart(cmd)
 		if err != nil {
 			return err
 		}
@@ -180,9 +180,13 @@ func editAction(cmd *cobra.Command, args []string) error {
 	return instance.Start(ctx, inst, false, false)
 }
 
-func askWhetherToStart() (bool, error) {
-	message := "Do you want to start the instance now? "
-	return uiutil.Confirm(message, true)
+func askWhetherToStart(cmd *cobra.Command) (bool, error) {
+	isTTY := uiutil.InputIsTTY(cmd.InOrStdin())
+	if isTTY {
+		message := "Do you want to start the instance now? "
+		return uiutil.Confirm(message, true)
+	}
+	return false, nil
 }
 
 func editBashComplete(cmd *cobra.Command, _ []string, _ string) ([]string, cobra.ShellCompDirective) {

cmd/limactl/shell.go

@@ -70,6 +70,10 @@ func newShellCommand() *cobra.Command {
 func shellAction(cmd *cobra.Command, args []string) error {
 	ctx := cmd.Context()
 	flags := cmd.Flags()
+	tty, err := flags.GetBool("tty")
+	if err != nil {
+		return err
+	}
 	// simulate the behavior of double dash
 	newArg := []string{}
 	if len(args) >= 2 && args[1] == "--" {
@@ -106,8 +110,8 @@ func shellAction(cmd *cobra.Command, args []string) error {
 			return err
 		}
 
-		if !flags.Changed("start") {
-			startNow, err = askWhetherToStart()
+		if tty && !flags.Changed("start") {
+			startNow, err = askWhetherToStart(cmd)
 			if err != nil {
 				return err
 			}

hack/bats/tests/shell.bats

@@ -0,0 +1,31 @@
+# SPDX-FileCopyrightText: Copyright The Lima Authors
+# SPDX-License-Identifier: Apache-2.0
+
+load "../helpers/load"
+
+NAME=dummy
+
+local_setup_file() {
+    for INSTANCE in "$NAME"; do
+        limactl delete --force "$INSTANCE" || :
+    done
+}
+
+@test 'create dummy instance' {
+    run -0 create_dummy_instance "$NAME" '.disk = "1M"'
+}
+
+@test 'lima stopped lima instance' {
+    # check that the "tty" flag is used, also for stdin
+    limactl shell --tty=false "$NAME" true </dev/null
+}
+
+@test 'yes | stopped lima instance' {
+    # check that stdin is verified and not just crashing
+    bash -c "yes | limactl shell --tty=true $NAME true"
+}
+
+@test 'delete dummy instance' {
+    run_e -0 limactl delete --force "$NAME"
+    assert_info "Deleted \"${NAME}\"…"
+}

pkg/uiutil/uiutil.go

@@ -41,6 +41,12 @@ func Select(message string, options []string) (int, error) {
 	return ans, nil
 }
 
+// InputIsTTY returns true if reader is coming from stdin, and stdin is a terminal device,
+// not a regular file, stream, or pipe etc.
+func InputIsTTY(reader io.Reader) bool {
+	return reader == os.Stdin && (isatty.IsTerminal(os.Stdin.Fd()) || isatty.IsCygwinTerminal(os.Stdin.Fd()))
+}
+
 // OutputIsTTY returns true if writer is going to stdout, and stdout is a terminal device,
 // not a regular file, stream, or pipe etc.
 func OutputIsTTY(writer io.Writer) bool {