Added checkbox locked choices feature

README.md

@@ -114,7 +114,9 @@ questions = [
 answers = inquirer.prompt(questions)
 ```
 
-Checkbox questions can take one extra argument `carousel=False`. If set to true, the answers will rotate (back to first when pressing down on last choice, and down to last choice when pressing up on first choice)
+Checkbox questions can take extra argument `carousel=False`. If set to true, the answers will rotate (back to first when pressing down on last choice, and down to last choice when pressing up on first choice)
+
+Another argument that can be used is `locked=<List>`. The given choices in the locked argument cannot be removed. This is useful if you want to make clear that a specific option out of the choices must be chosen.
 
 ### Path
 

examples/checkbox_locked.py

@@ -0,0 +1,21 @@
+import os
+import sys
+from pprint import pprint
+
+
+sys.path.append(os.path.realpath("."))
+import inquirer  # noqa
+
+
+questions = [
+    inquirer.Checkbox(
+        "courses",
+        message="Which courses would you like to take?",
+        choices=["Programming fundamentals", "Fullstack development", "Data science", "DevOps"],
+        locked=["Programming fundamentals"],
+    ),
+]
+
+answers = inquirer.prompt(questions)
+
+pprint(answers)

src/inquirer/questions.py

@@ -164,6 +164,7 @@ def __init__(
         name,
         message="",
         choices=None,
+        locked=None,
         default=None,
         ignore=False,
         validate=True,
@@ -173,6 +174,7 @@ def __init__(
     ):
 
         super().__init__(name, message, choices, default, ignore, validate, other=other)
+        self.locked = locked
         self.carousel = carousel
         self.autocomplete = autocomplete
 

src/inquirer/render/console/_checkbox.py

@@ -10,9 +10,14 @@
 class Checkbox(BaseConsoleRender):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
-        self.selection = [k for (k, v) in enumerate(self.question.choices) if v in (self.question.default or [])]
+        self.locked = self.question.locked or []
+        self.selection = [k for (k, v) in enumerate(self.question.choices) if v in self.set_default_choices()]
         self.current = 0
 
+    def set_default_choices(self):
+        default = self.question.default or []
+        return default + self.locked
+
     @property
     def is_long(self):
         choices = self.question.choices or []
@@ -39,14 +44,12 @@ def get_options(self):
         is_in_beginning = self.current <= half_options
         is_in_middle = half_options < self.current < ending_milestone
         is_in_end = self.current >= ending_milestone
-
         for index, choice in enumerate(cchoices):
             if (
                 (is_in_middle and self.current - half_options + index in self.selection)
                 or (is_in_beginning and index in self.selection)
                 or (is_in_end and index + max(len(choices) - MAX_OPTIONS_DISPLAYED_AT_ONCE, 0) in self.selection)
             ):  # noqa
-
                 symbol = self.theme.Checkbox.selected_icon
                 color = self.theme.Checkbox.selected_color
             else:
@@ -60,17 +63,20 @@ def get_options(self):
                 or (is_in_beginning and index == self.current)
                 or (is_in_end and end_index == self.current)
             ):
-
                 selector = self.theme.Checkbox.selection_icon
                 color = self.theme.Checkbox.selection_color
 
+            if choice in self.locked:
+                color = self.theme.Checkbox.locked_option_color
+
             if choice == GLOBAL_OTHER_CHOICE:
                 symbol = "+"
 
             yield choice, selector + " " + symbol, color
 
     def process_input(self, pressed):
         question = self.question
+        is_current_choice_locked = question.choices[self.current] in self.locked
         if pressed == key.UP:
             if question.carousel and self.current == 0:
                 self.current = len(question.choices) - 1
@@ -87,12 +93,14 @@ def process_input(self, pressed):
             if self.question.choices[self.current] == GLOBAL_OTHER_CHOICE:
                 self.other_input()
             elif self.current in self.selection:
-                self.selection.remove(self.current)
+                if not is_current_choice_locked:
+                    self.selection.remove(self.current)
             else:
                 self.selection.append(self.current)
         elif pressed == key.LEFT:
             if self.current in self.selection:
-                self.selection.remove(self.current)
+                if not is_current_choice_locked:
+                    self.selection.remove(self.current)
         elif pressed == key.RIGHT:
             if self.current not in self.selection:
                 self.selection.append(self.current)

src/inquirer/themes.py

@@ -93,6 +93,7 @@ def __init__(self):
         self.Checkbox.selected_color = term.yellow + term.bold
         self.Checkbox.unselected_color = term.normal
         self.Checkbox.unselected_icon = "[ ]"
+        self.Checkbox.locked_option_color = term.gray50
         self.List.selection_color = term.blue
         self.List.selection_cursor = ">"
         self.List.unselected_color = term.normal

tests/acceptance/test_checkbox.py

@@ -147,3 +147,27 @@ def setUp(self):
     def test_default_selection(self):
         self.sut.send(key.ENTER)
         self.sut.expect("{'interests': ", timeout=1)
+
+
+@unittest.skipUnless(sys.platform.startswith("lin"), "Linux only")
+class CheckLockedTest(unittest.TestCase):
+    def setUp(self):
+        self.sut = pexpect.spawn("python examples/checkbox_locked.py")
+        self.sut.expect("DevOps.*", timeout=1)
+
+    def test_default_selection(self):
+        self.sut.send(key.ENTER)
+        self.sut.expect(r"{'courses': \['Programming fundamentals'\]}", timeout=1)
+
+    def test_locked_option(self):
+        self.sut.send(key.SPACE)
+        self.sut.send(key.LEFT)
+        self.sut.send(key.ENTER)
+        self.sut.expect(r"{'courses': \['Programming fundamentals'\]}", timeout=1)
+
+    def test_locked_with_another_option(self):
+        self.sut.send(key.DOWN)
+        self.sut.send(key.DOWN)
+        self.sut.send(key.SPACE)
+        self.sut.send(key.ENTER)
+        self.sut.expect(r"{'courses': \['Programming fundamentals', 'Data science'\]}", timeout=1)

tests/integration/console_render/test_checkbox.py

@@ -324,3 +324,59 @@ def test_double_invert_all(self):
         result = sut.render(question)
 
         assert result == []
+
+    def test_unselect_locked(self):
+        stdin_array = [key.SPACE, key.LEFT, key.ENTER]
+        stdin = helper.event_factory(*stdin_array)
+        message = "Foo message"
+        variable = "Bar variable"
+        choices = ["foo", "bar", "bazz"]
+
+        question = questions.Checkbox(variable, message, choices=choices, locked=["foo"])
+
+        sut = ConsoleRender(event_generator=stdin)
+        result = sut.render(question)
+
+        assert result == ["foo"]
+
+    def test_two_locked_options(self):
+        stdin_array = [key.ENTER]
+        stdin = helper.event_factory(*stdin_array)
+        message = "Foo message"
+        variable = "Bar variable"
+        choices = ["foo", "bar", "bazz"]
+
+        question = questions.Checkbox(variable, message, choices=choices, locked=["foo", "bazz"])
+
+        sut = ConsoleRender(event_generator=stdin)
+        result = sut.render(question)
+
+        assert result == ["foo", "bazz"]
+
+    def test_locked_with_typo(self):
+        stdin_array = [key.ENTER]
+        stdin = helper.event_factory(*stdin_array)
+        message = "Foo message"
+        variable = "Bar variable"
+        choices = ["foo", "bar", "bazz"]
+
+        question = questions.Checkbox(variable, message, choices=choices, locked=["fooo"])
+
+        sut = ConsoleRender(event_generator=stdin)
+        result = sut.render(question)
+
+        assert result == []
+
+    def test_locked_with_default(self):
+        stdin_array = [key.DOWN, key.SPACE, key.ENTER]
+        stdin = helper.event_factory(*stdin_array)
+        message = "Foo message"
+        variable = "Bar variable"
+        choices = ["foo", "bar", "bazz"]
+
+        question = questions.Checkbox(variable, message, choices=choices, locked=["bar"], default=["bar"])
+
+        sut = ConsoleRender(event_generator=stdin)
+        result = sut.render(question)
+
+        assert result == ["bar"]