[terminal buffering] Remove the management of the iTerm2-specific buffering protocol

Since iTerm2 also supports the "mode 2026", we can just rely on that one ✌

src/textual/_ansi_sequences.py

@@ -1,7 +1,7 @@
 from typing import Dict, Tuple
 
 from ._terminal_modes import (
-    get__mode_report_sequence,
+    get_mode_report_sequence,
     Mode,
     ModeReportParameter,
 )
@@ -308,8 +308,12 @@ ANSI_SEQUENCES_KEYS: Dict[str, Tuple[Keys, ...]] = {
 
 # Mapping of escape codes to report whether they support a "mode" we requested.
 ANSI_SEQUENCES_MODE_REPORTS: Dict[str, Tuple[Mode, ModeReportParameter]] = {
-    get__mode_report_sequence(mode, parameter): (mode, parameter)
+    get_mode_report_sequence(mode, parameter): (mode, parameter)
     for mode, parameter in [
         (mode, parameter) for parameter in ModeReportParameter for mode in Mode
     ]
 }
+
+TERMINAL_MODES_ANSI_SEQUENCES: Dict[Mode, dict] = {
+    Mode.SynchronizedOutput: {"start_sync": "\x1b[?2026h", "end_sync": "\x1b[?2026l"},
+}

src/textual/_terminal_features.py

@@ -1,17 +1,15 @@
 from __future__ import annotations
-import os
+from typing import NamedTuple
-import platform
+
-from dataclasses import dataclass
+from textual._ansi_sequences import TERMINAL_MODES_ANSI_SEQUENCES
+from textual._terminal_modes import Mode
 
 
-@dataclass
+class TerminalSupportedFeatures(NamedTuple):
-class TerminalSupportedFeatures:
     """
     Handles information about the features the current terminal emulator seems to support.
     """
 
-    iterm2_synchronized_update: bool = False
-    """@link https://gitlab.com/gnachman/iterm2/-/wikis/synchronized-updates-spec"""
     mode2026_synchronized_update: bool = False
     """@link https://gist.github.com/christianparpart/d8a62cc1ab659194337d73e399004036"""
 
@@ -26,19 +24,15 @@ class TerminalSupportedFeatures:
             TerminalSupportedFeatures: a new TerminalSupportedFeatures
         """
 
-        # Using macOS, but not using the default terminal: let's assume we're on iTerm2
+        # Here we might detect some features later on, by checking the OS type, the env vars, etc.
-        iterm2_synchronized_update = (
+        # (the same way we were doing it to detect iTerm2 "synchronized update" mode)
-            platform.system() == "Darwin"
-            and os.environ.get("TERM_PROGRAM", "") != "Apple_Terminal"
-        )
 
-        # Detecting "mode2026" is more complicated, as we have to use an async request/response
+        # Detecting "mode2026" is complicated, as we have to use an async request/response
         # machinery with the terminal emulator - for now we should just assume it's not supported.
         # See the use of the Mode and ModeReportParameter classes in the Textual code to check this machinery.
         mode2026_synchronized_update = False
 
         return cls(
-            iterm2_synchronized_update=iterm2_synchronized_update,
             mode2026_synchronized_update=mode2026_synchronized_update,
         )
 
@@ -47,12 +41,12 @@ class TerminalSupportedFeatures:
         """
         Tells the caller if the current terminal emulator seems to support "synchronised updates"
         (i.e. "buffered" updates).
-        At the moment we support the iTerm2 specific one, as wel las the more generic "mode 2026".
+        At the moment we only support the generic "mode 2026".
 
         Returns:
             bool: whether the terminal seems to support buffered mode or not
         """
-        return self.iterm2_synchronized_update or self.mode2026_synchronized_update
+        return self.mode2026_synchronized_update
 
     def synchronized_update_sequences(self) -> tuple[str, str]:
         """
@@ -70,15 +64,11 @@ class TerminalSupportedFeatures:
         )
 
     def _synchronized_update_start_sequence(self) -> str:
-        if self.iterm2_synchronized_update:
-            return "\x1bP=1s\x1b\\"
         if self.mode2026_synchronized_update:
-            return "\x1b[?2026h"
+            return TERMINAL_MODES_ANSI_SEQUENCES[Mode.SynchronizedOutput]["start_sync"]
         return ""
 
     def _synchronized_update_end_sequence(self) -> str:
-        if self.iterm2_synchronized_update:
-            return "\x1bP=2s\x1b\\"
         if self.mode2026_synchronized_update:
-            return "\x1b[?2026l"
+            return TERMINAL_MODES_ANSI_SEQUENCES[Mode.SynchronizedOutput]["end_sync"]
         return ""

src/textual/_terminal_modes.py

@@ -37,5 +37,5 @@ def get_mode_request_sequence(mode: Mode) -> str:
     return "\033[?" + mode.value + "$p\n"
 
 
-def get__mode_report_sequence(mode: Mode, parameter: ModeReportParameter) -> str:
+def get_mode_report_sequence(mode: Mode, parameter: ModeReportParameter) -> str:
     return f"\x1b[?{mode.value};{parameter.value}$y"

src/textual/app.py

@@ -952,7 +952,9 @@ class App(Generic[ReturnType], DOMNode):
                 log(
                     f"SynchronizedOutput (aka 'mode2026') {'is' if is_supported else ' is not'} supported"
                 )
-                self._terminal_features.mode2026_synchronized_update = is_supported
+                self._terminal_features = self._terminal_features._replace(
+                    mode2026_synchronized_update=is_supported
+                )
 
         else:
             await super().on_event(event)

src/textual/drivers/linux_driver.py

@@ -127,7 +127,7 @@ class LinuxDriver(Driver):
         self._request_terminal_mode_support(Mode.SynchronizedOutput)
 
     def _request_terminal_mode_support(self, mode: Mode):
-        self.console.file.write(get_mode_request_sequence(mode) + "\n")
+        self.console.file.write(get_mode_request_sequence(mode))
         self.console.file.flush()
 
     @classmethod

tests/utilities/test_app.py

@@ -15,7 +15,9 @@ from textual import events, errors
 from textual._clock import _Clock
 from textual.app import WINDOWS
 from textual._context import active_app
+from textual._ansi_sequences import TERMINAL_MODES_ANSI_SEQUENCES
 from textual._terminal_features import TerminalSupportedFeatures
+from textual._terminal_modes import Mode
 from textual.app import App, ComposeResult
 from textual.driver import Driver
 from textual.geometry import Size, Region
@@ -23,8 +25,9 @@ from textual.geometry import Size, Region
 # N.B. These classes would better be named TestApp/TestConsole/TestDriver/etc,
 # but it makes pytest emit warning as it will try to collect them as classes containing test cases :-/
 
-# This value is also hard-coded in Textual's `App` class:
+CLEAR_SCREEN_SEQUENCE = TERMINAL_MODES_ANSI_SEQUENCES[Mode.SynchronizedOutput][
-CLEAR_SCREEN_SEQUENCE = "\x1bP=1s\x1b\\"
+    "start_sync"
+]
 
 
 class AppTest(App):
@@ -47,12 +50,11 @@ class AppTest(App):
         # Let's disable all features by default
         self.features = frozenset()
 
-        # We need this so the iTerm2 `CLEAR_SCREEN_SEQUENCE` is always sent for a screen refresh,
+        # We need this so the `CLEAR_SCREEN_SEQUENCE` is always sent for a screen refresh,
         # whatever the environment:
         # (we use it to slice the output into distinct full screens displays)
         self._terminal_features = TerminalSupportedFeatures(
-            iterm2_synchronized_update=True,
+            mode2026_synchronized_update=True,
-            mode2026_synchronized_update=False,
         )
 
         self._size = size
@@ -347,7 +349,6 @@ class ClockMock(_Clock):
             # ...and let's mark it for removal:
             activated_events_times_to_clear.append(monotonic_time)
 
-        if activated_events_times_to_clear:
         for event_time_to_clear in activated_events_times_to_clear:
             del self._pending_sleep_events[event_time_to_clear]