feat(keyboard): Add persistent and placeholder options

Introduce `persistent` and `placeholder` parameters for `ReplyKeyboardMarkup`.
These new options control keyboard visibility and input field text.
Available for text, location, phone, and poll buttons.

Remove vestigial `inline_only` from `build_reply_markup` as its functionality is
implicitly covered by the general rule against mixing inline and
normal buttons.

telethon/client/buttons.py

@@ -7,8 +7,8 @@ from ..tl import types, custom
 class ButtonMethods:
     @staticmethod
     def build_reply_markup(
-            buttons: 'typing.Optional[hints.MarkupLike]',
+            buttons: 'typing.Optional[hints.MarkupLike]'
-            inline_only: bool = False) -> 'typing.Optional[types.TypeReplyMarkup]':
+    ) -> 'typing.Optional[types.TypeReplyMarkup]':
         """
         Builds a :tl:`ReplyInlineMarkup` or :tl:`ReplyKeyboardMarkup` for
         the given buttons.
@@ -26,9 +26,6 @@ class ButtonMethods:
                 The button, list of buttons, array of buttons or markup
                 to convert into a markup.
 
-            inline_only (`bool`, optional):
-                Whether the buttons **must** be inline buttons only or not.
-
         Example
             .. code-block:: python
 
@@ -42,8 +39,8 @@ class ButtonMethods:
             return None
 
         try:
-            if buttons.SUBCLASS_OF_ID == 0xe2e10ef2:
+            if buttons.SUBCLASS_OF_ID == 0xe2e10ef2:  # crc32(b'ReplyMarkup'):
-                return buttons  # crc32(b'ReplyMarkup'):
+                return buttons
         except AttributeError:
             pass
 
@@ -57,6 +54,8 @@ class ButtonMethods:
         resize = None
         single_use = None
         selective = None
+        persistent = None
+        placeholder = None
 
         rows = []
         for row in buttons:
@@ -69,6 +68,10 @@ class ButtonMethods:
                         single_use = button.single_use
                     if button.selective is not None:
                         selective = button.selective
+                    if button.persistent is not None:
+                        persistent = button.persistent
+                    if button.placeholder is not None:
+                        placeholder = button.placeholder
 
                     button = button.button
                 elif isinstance(button, custom.MessageButton):
@@ -78,19 +81,21 @@ class ButtonMethods:
                 is_inline |= inline
                 is_normal |= not inline
 
-                if button.SUBCLASS_OF_ID == 0xbad74a3:
+                if button.SUBCLASS_OF_ID == 0xbad74a3:  # crc32(b'KeyboardButton')
-                    # 0xbad74a3 == crc32(b'KeyboardButton')
                     current.append(button)
 
             if current:
                 rows.append(types.KeyboardButtonRow(current))
 
-        if inline_only and is_normal:
+        if is_inline and is_normal:
-            raise ValueError('You cannot use non-inline buttons here')
-        elif is_inline == is_normal and is_normal:
             raise ValueError('You cannot mix inline with normal buttons')
         elif is_inline:
             return types.ReplyInlineMarkup(rows)
-        # elif is_normal:
         return types.ReplyKeyboardMarkup(
-            rows, resize=resize, single_use=single_use, selective=selective)
+            rows=rows,
+            resize=resize,
+            single_use=single_use,
+            selective=selective,
+            persistent=persistent,
+            placeholder=placeholder
+        )

telethon/tl/custom/button.py

@@ -37,11 +37,14 @@ class Button:
     to 128 characters and add the ellipsis (…) character as
     the 129.
     """
-    def __init__(self, button, *, resize, single_use, selective):
+    def __init__(self, button, *, resize, single_use, selective,
+                 persistent, placeholder):
         self.button = button
         self.resize = resize
         self.single_use = single_use
         self.selective = selective
+        self.persistent = persistent
+        self.placeholder = placeholder
 
     @staticmethod
     def _is_inline(button):
@@ -168,11 +171,15 @@ class Button:
         )
 
     @classmethod
-    def text(cls, text, *, resize=None, single_use=None, selective=None):
+    def text(cls, text, *, resize=None, single_use=None, selective=None,
+             persistent=None, placeholder=None):
         """
         Creates a new keyboard button with the given text.
 
         Args:
+            text (`str`):
+                The title of the button.
+
             resize (`bool`):
                 If present, the entire keyboard will be reconfigured to
                 be resized and be smaller if there are not many buttons.
@@ -187,48 +194,77 @@ class Button:
                 users. It will target users that are @mentioned in the text
                 of the message or to the sender of the message you reply to.
 
+            persistent (`bool`):
+                If present, always show the keyboard when the regular keyboard
+                is hidden. Defaults to false, in which case the custom keyboard
+                can be hidden and revealed via the keyboard icon.
+
+            placeholder (`str`):
+                The placeholder to be shown in the input field when the keyboard is active;
+                1-64 characters
+
         When the user clicks this button, a text message with the same text
         as the button will be sent, and can be handled with `events.NewMessage
         <telethon.events.newmessage.NewMessage>`. You cannot distinguish
         between a button press and the user typing and sending exactly the
         same text on their own.
         """
-        return cls(types.KeyboardButton(text),
+        return cls(
-                   resize=resize, single_use=single_use, selective=selective)
+            types.KeyboardButton(text),
+            resize=resize,
+            single_use=single_use,
+            selective=selective,
+            persistent=persistent,
+            placeholder=placeholder
+        )
 
     @classmethod
-    def request_location(cls, text, *,
+    def request_location(cls, text, *, resize=None, single_use=None, selective=None,
-                         resize=None, single_use=None, selective=None):
+                         persistent=None, placeholder=None):
         """
         Creates a new keyboard button to request the user's location on click.
 
-        ``resize``, ``single_use`` and ``selective`` are documented in `text`.
+        ``resize``, ``single_use``, ``selective``, ``persistent`` and ``placeholder``
+         are documented in `text`.
 
         When the user clicks this button, a confirmation box will be shown
         to the user asking whether they want to share their location with the
         bot, and if confirmed a message with geo media will be sent.
         """
-        return cls(types.KeyboardButtonRequestGeoLocation(text),
+        return cls(
-                   resize=resize, single_use=single_use, selective=selective)
+            types.KeyboardButtonRequestGeoLocation(text),
+            resize=resize,
+            single_use=single_use,
+            selective=selective,
+            persistent=persistent,
+            placeholder=placeholder
+        )
 
     @classmethod
-    def request_phone(cls, text, *,
+    def request_phone(cls, text, *, resize=None, single_use=None,
-                      resize=None, single_use=None, selective=None):
+                      selective=None, persistent=None, placeholder=None):
         """
         Creates a new keyboard button to request the user's phone on click.
 
-        ``resize``, ``single_use`` and ``selective`` are documented in `text`.
+        ``resize``, ``single_use``, ``selective``, ``persistent`` and ``placeholder``
+         are documented in `text`.
 
         When the user clicks this button, a confirmation box will be shown
         to the user asking whether they want to share their phone with the
         bot, and if confirmed a message with contact media will be sent.
         """
-        return cls(types.KeyboardButtonRequestPhone(text),
+        return cls(
-                   resize=resize, single_use=single_use, selective=selective)
+            types.KeyboardButtonRequestPhone(text),
+            resize=resize,
+            single_use=single_use,
+            selective=selective,
+            placeholder=placeholder,
+            persistent=persistent
+        )
 
     @classmethod
-    def request_poll(cls, text, *, force_quiz=False,
+    def request_poll(cls, text, *, force_quiz=False, resize=None, single_use=None,
-                     resize=None, single_use=None, selective=None):
+                     selective=None, persistent=None, placeholder=None):
         """
         Creates a new keyboard button to request the user to create a poll.
 
@@ -240,13 +276,20 @@ class Button:
         the votes cannot be retracted. Otherwise, users can vote and retract
         the vote, and the pol might be multiple choice.
 
-        ``resize``, ``single_use`` and ``selective`` are documented in `text`.
+        ``resize``, ``single_use``, ``selective``, ``persistent`` and ``placeholder``
+         are documented in `text`.
 
         When the user clicks this button, a screen letting the user create a
         poll will be shown, and if they do create one, the poll will be sent.
         """
-        return cls(types.KeyboardButtonRequestPoll(text, quiz=force_quiz),
+        return cls(
-                   resize=resize, single_use=single_use, selective=selective)
+            types.KeyboardButtonRequestPoll(text, quiz=force_quiz),
+            resize=resize,
+            single_use=single_use,
+            selective=selective,
+            persistent=persistent,
+            placeholder=placeholder
+        )
 
     @staticmethod
     def clear(selective=None):
@@ -265,15 +308,8 @@ class Button:
         Forces a reply to the message with this markup. If used,
         no other button should be present or it will be ignored.
 
-        ``single_use`` and ``selective`` are as documented in `text`.
+        ``single_use``, ``selective`` and ``placeholder`` are as documented in `text`.
 
-        Args:
-            placeholder (str):
-                text to show the user at typing place of message.
-
-                If the placeholder is too long, Telegram applications will
-                crop the text (for example, to 64 characters and adding an
-                ellipsis (…) character as the 65th).
         """
         return types.ReplyKeyboardForceReply(
             single_use=single_use,