Fix animation of long lines

src/pipx/animate.py

@@ -2,12 +2,22 @@
 from contextlib import contextmanager
 from threading import Event, Thread
 from typing import Generator, List
+import shutil
 
 from pipx.constants import emoji_support
 
 stderr_is_tty = sys.stderr.isatty()
 
 
+HIDE_CURSOR = "\033[?25l"
+SHOW_CURSOR = "\033[?25h"
+CLEAR_LINE = "\033[K"
+EMOJI_ANIMATION_FRAMES = ["⣷", "⣯", "⣟", "⡿", "⢿", "⣻", "⣽", "⣾"]
+NONEMOJI_ANIMATION_FRAMES = ["", ".", "..", "..."]
+EMOJI_FRAME_PERIOD = 0.1
+NONEMOJI_FRAME_PERIOD = 1
+
+
 @contextmanager
 def animate(message: str, do_animation: bool) -> Generator[None, None, None]:
 
@@ -20,12 +30,12 @@ def animate(message: str, do_animation: bool) -> Generator[None, None, None]:
 
     if emoji_support:
         animate_at_beginning_of_line = True
-        symbols = ["⣷", "⣯", "⣟", "⡿", "⢿", "⣻", "⣽", "⣾"]
-        period = 0.1
+        symbols = EMOJI_ANIMATION_FRAMES
+        period = EMOJI_FRAME_PERIOD
     else:
         animate_at_beginning_of_line = False
-        symbols = ["", ".", "..", "..."]
-        period = 1
+        symbols = NONEMOJI_ANIMATION_FRAMES
+        period = NONEMOJI_FRAME_PERIOD
 
     thread_kwargs = {
         "message": message,
@@ -59,12 +69,17 @@ def print_animation(
     period: float,
     animate_at_beginning_of_line: bool,
 ):
+    (term_cols, _) = shutil.get_terminal_size(fallback=(9999, 24))
     while not event.wait(0):
         for s in symbols:
             if animate_at_beginning_of_line:
-                cur_line = f"{s} {message}"
+                max_message_len = term_cols - len(f"{s} ... ")
+                cur_line = f"{s} {message:.{max_message_len}}"
+                if len(message) > max_message_len:
+                    cur_line += "..."
             else:
-                cur_line = f"{message}{s}"
+                max_message_len = term_cols - len("... ")
+                cur_line = f"{message:.{max_message_len}}{s}"
 
             clear_line()
             sys.stderr.write("\r")
@@ -74,13 +89,13 @@ def print_animation(
 
 
 def hide_cursor():
-    sys.stderr.write("\033[?25l")
+    sys.stderr.write(f"{HIDE_CURSOR}")
 
 
 def show_cursor():
-    sys.stderr.write("\033[?25h")
+    sys.stderr.write(f"{SHOW_CURSOR}")
 
 
 def clear_line():
-    sys.stderr.write("\033[K")
-    sys.stdout.write("\033[K")
+    sys.stderr.write(f"{CLEAR_LINE}")
+    sys.stdout.write(f"{CLEAR_LINE}")

tests/test_animate.py

@@ -0,0 +1,76 @@
+import time
+
+import pipx.animate
+from pipx.animate import (
+    HIDE_CURSOR,
+    CLEAR_LINE,
+    EMOJI_ANIMATION_FRAMES,
+    NONEMOJI_ANIMATION_FRAMES,
+    EMOJI_FRAME_PERIOD,
+    NONEMOJI_FRAME_PERIOD,
+)
+
+
+def check_animate_output(
+    capsys, test_string, frame_strings, frame_period, frames_to_test
+):
+    expected_string = f"{HIDE_CURSOR}" + "".join(frame_strings)
+
+    chars_to_test = 1 + len("".join(frame_strings[:frames_to_test]))
+
+    with pipx.animate.animate(test_string, do_animation=True):
+        time.sleep(frame_period * (frames_to_test - 1) + 0.2)
+    captured = capsys.readouterr()
+
+    assert captured.err[:chars_to_test] == expected_string[:chars_to_test]
+
+
+def test_line_lengths_emoji(capsys, monkeypatch):
+    # emoji_support and stderr_is_tty is set only at import animate.py
+    # since we are already after that, we must override both here
+    monkeypatch.setattr(pipx.animate, "stderr_is_tty", True)
+    monkeypatch.setattr(pipx.animate, "emoji_support", True)
+
+    frames_to_test = 4
+
+    # 40-char test_string counts columns e.g.: "0204060810 ... 363840"
+    test_string = "".join([f"{x:02}" for x in range(2, 41, 2)])
+
+    columns_to_test = [45, 46, 47]
+    expected_message = [f"{test_string:.{45-6}}...", f"{test_string}", f"{test_string}"]
+
+    for i, columns in enumerate(columns_to_test):
+        monkeypatch.setenv("COLUMNS", str(columns))
+
+        frame_strings = [
+            f"{CLEAR_LINE}\r{x} {expected_message[i]}" for x in EMOJI_ANIMATION_FRAMES
+        ]
+        check_animate_output(
+            capsys, test_string, frame_strings, EMOJI_FRAME_PERIOD, frames_to_test
+        )
+
+
+def test_line_lengths_no_emoji(capsys, monkeypatch):
+    # emoji_support and stderr_is_tty is set only at import animate.py
+    # since we are already after that, we must override both here
+    monkeypatch.setattr(pipx.animate, "stderr_is_tty", True)
+    monkeypatch.setattr(pipx.animate, "emoji_support", False)
+
+    frames_to_test = 2
+
+    # 40-char test_string counts columns e.g.: "0204060810 ... 363840"
+    test_string = "".join([f"{x:02}" for x in range(2, 41, 2)])
+
+    columns_to_test = [43, 44, 45]
+    expected_message = [f"{test_string:.{43-4}}", f"{test_string}", f"{test_string}"]
+
+    for i, columns in enumerate(columns_to_test):
+        monkeypatch.setenv("COLUMNS", str(columns))
+
+        frame_strings = [
+            f"{CLEAR_LINE}\r{expected_message[i]}{x}" for x in NONEMOJI_ANIMATION_FRAMES
+        ]
+
+        check_animate_output(
+            capsys, test_string, frame_strings, NONEMOJI_FRAME_PERIOD, frames_to_test
+        )