fix: prevent action execution during shell completion after double dash

app.go

@@ -319,7 +319,14 @@ func (a *App) RunContext(ctx context.Context, arguments []string) (err error) {
 	// flag name as the value of the flag before it which is undesirable
 	// note that we can only do this because the shell autocomplete function
 	// always appends the completion flag at the end of the command
-	shellComplete, arguments := checkShellCompleteFlag(a, arguments)
+	shellComplete, completionDetected, arguments := checkShellCompleteFlag(a, arguments)
+
+	// If the completion flag was present but shell completion is disabled
+	// (e.g., because "--" was on the command line), do not execute the
+	// action. The flag has already been stripped from arguments.
+	if completionDetected && !shellComplete {
+		return nil
+	}
 
 	cCtx := NewContext(a, nil, &Context{Context: ctx})
 	cCtx.shellComplete = shellComplete

help.go

@@ -435,28 +435,34 @@ func checkHelp(cCtx *Context) bool {
 	return found
 }
 
-func checkShellCompleteFlag(a *App, arguments []string) (bool, []string) {
+func checkShellCompleteFlag(a *App, arguments []string) (bool, bool, []string) {
 	if !a.EnableBashCompletion {
-		return false, arguments
+		return false, false, arguments
 	}
 
 	pos := len(arguments) - 1
 	lastArg := arguments[pos]
 
 	if lastArg != "--generate-bash-completion" {
-		return false, arguments
+		return false, false, arguments
 	}
 
+	// The completion flag was detected — strip it from arguments regardless
+	// of "--" presence, so that it never leaks into the action's arguments.
+	stripped := make([]string, 0, len(arguments)-1)
+	stripped = append(stripped, arguments[:pos]...)
+	stripped = append(stripped, arguments[pos+1:]...)
+
 	for _, arg := range arguments {
 		// If arguments include "--", shell completion is disabled
 		// because after "--" only positional arguments are accepted.
 		// https://unix.stackexchange.com/a/11382
 		if arg == "--" {
-			return false, arguments
+			return false, true, stripped
 		}
 	}
 
-	return true, arguments[:pos]
+	return true, true, stripped
 }
 
 func checkCompletions(cCtx *Context) bool {

help_test.go

@@ -1716,57 +1716,66 @@ GLOBAL OPTIONS:
 func Test_checkShellCompleteFlag(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
-		name                string
-		app                 *App
-		arguments           []string
-		wantShellCompletion bool
-		wantArgs            []string
+		name                   string
+		app                    *App
+		arguments              []string
+		wantShellCompletion    bool
+		wantCompletionDetected bool
+		wantArgs               []string
 	}{
 		{
-			name:                "disable bash completion",
-			arguments:           []string{"--generate-bash-completion"},
-			app:                 &App{},
-			wantShellCompletion: false,
-			wantArgs:            []string{"--generate-bash-completion"},
+			name:                   "disable bash completion",
+			arguments:              []string{"--generate-bash-completion"},
+			app:                    &App{},
+			wantShellCompletion:    false,
+			wantCompletionDetected: false,
+			wantArgs:               []string{"--generate-bash-completion"},
 		},
 		{
 			name:      "--generate-bash-completion isn't used",
 			arguments: []string{"foo"},
 			app: &App{
 				EnableBashCompletion: true,
 			},
-			wantShellCompletion: false,
-			wantArgs:            []string{"foo"},
+			wantShellCompletion:    false,
+			wantCompletionDetected: false,
+			wantArgs:               []string{"foo"},
 		},
 		{
 			name:      "arguments include double dash",
 			arguments: []string{"--", "foo", "--generate-bash-completion"},
 			app: &App{
 				EnableBashCompletion: true,
 			},
-			wantShellCompletion: false,
-			wantArgs:            []string{"--", "foo", "--generate-bash-completion"},
+			wantShellCompletion:    false,
+			wantCompletionDetected: true,
+			wantArgs:               []string{"--", "foo"},
 		},
 		{
 			name:      "--generate-bash-completion",
 			arguments: []string{"foo", "--generate-bash-completion"},
 			app: &App{
 				EnableBashCompletion: true,
 			},
-			wantShellCompletion: true,
-			wantArgs:            []string{"foo"},
+			wantShellCompletion:    true,
+			wantCompletionDetected: true,
+			wantArgs:               []string{"foo"},
 		},
 	}
 
 	for _, tt := range tests {
 		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
-			shellCompletion, args := checkShellCompleteFlag(tt.app, tt.arguments)
+			shellCompletion, completionDetected, args := checkShellCompleteFlag(tt.app, tt.arguments)
 			if tt.wantShellCompletion != shellCompletion {
 				t.Errorf("Unexpected shell completion, got:\n%v\nexpected: %v",
 					shellCompletion, tt.wantShellCompletion)
 			}
+			if tt.wantCompletionDetected != completionDetected {
+				t.Errorf("Unexpected completion detected, got:\n%v\nexpected: %v",
+					completionDetected, tt.wantCompletionDetected)
+			}
 			if !reflect.DeepEqual(tt.wantArgs, args) {
 				t.Errorf("Unexpected arguments, got:\n%v\nexpected: %v",
 					args, tt.wantArgs)