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fix: use session's actual screen state for screenshots

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The screenshot was creating a new pyte screen with arbitrary dimensions
from query params, but the replay buffer contains ANSI sequences meant
for the session's actual terminal size. This mismatch caused wrapping.

Now we use get_screen_state() which returns the actual screen buffer
from the terminal session's pyte screen, with the correct dimensions.
This ensures the screenshot matches exactly what the terminal rendered.
This commit is contained in:
GitHub Copilot
2026-01-24 11:14:12 +00:00
parent 3e433f5af5
commit e85213315e
3 changed files with 81 additions and 61 deletions
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tests/test_local_server_unit.py
+33 -17
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@@ -191,11 +191,15 @@ class TestLocalServerHelpers:
@pytest.mark.asyncio
async def test_screenshot_svg_handler_returns_svg(self, server, monkeypatch, capsys):
request = MagicMock()
request.query = {"route_key": "rk", "width": "80"}
request.query = {"route_key": "rk"}
# Mock screen state: width=80, height=2, buffer with "hello" on first line
screen_buffer = [
[{"data": c, "fg": "default", "bg": "default", "bold": False, "italics": False, "underscore": False, "reverse": False} for c in "hello" + " " * 75],
[{"data": " ", "fg": "default", "bg": "default", "bold": False, "italics": False, "underscore": False, "reverse": False}] * 80,
]
session = MagicMock()
session.get_screen_lines = AsyncMock(return_value=["hello", ""])
session.get_replay_buffer = AsyncMock(return_value=b"hello\r\n")
session.get_screen_state = AsyncMock(return_value=(80, 2, screen_buffer))
monkeypatch.setattr(server.session_manager, "get_session_by_route_key", lambda _rk: session)
@@ -210,11 +214,15 @@ class TestLocalServerHelpers:
@pytest.mark.asyncio
async def test_screenshot_creates_session_for_known_slug(self, server, monkeypatch):
request = MagicMock()
request.query = {"route_key": "known", "width": "90"}
request.query = {"route_key": "known"}
# Mock screen state
screen_buffer = [
[{"data": c, "fg": "default", "bg": "default", "bold": False, "italics": False, "underscore": False, "reverse": False} for c in "world" + " " * 75],
[{"data": " ", "fg": "default", "bg": "default", "bold": False, "italics": False, "underscore": False, "reverse": False}] * 80,
]
session = MagicMock()
session.get_screen_lines = AsyncMock(return_value=["world", ""])
session.get_replay_buffer = AsyncMock(return_value=b"world\r\n")
session.get_screen_state = AsyncMock(return_value=(80, 2, screen_buffer))
# Pretend app exists for slug "known"
server.session_manager.apps_by_slug["known"] = App(
@@ -546,7 +554,7 @@ class TestLocalServerMoreCoverage:
request.headers = {}
session = MagicMock()
session.get_screen_lines = AsyncMock(return_value=["SHOULD_NOT_BE_READ"])
session.get_screen_state = AsyncMock(return_value=(80, 2, []))
monkeypatch.setattr(server_with_no_apps.session_manager, "get_session_by_route_key", lambda _rk: session)
server_with_no_apps._screenshot_cache["rk"] = (0.0, "<svg>cached</svg>")
@@ -556,17 +564,21 @@ class TestLocalServerMoreCoverage:
resp = await server_with_no_apps._handle_screenshot(request)
assert "cached" in resp.text
session.get_screen_lines.assert_not_awaited()
session.get_screen_state.assert_not_awaited()
@pytest.mark.asyncio
async def test_handle_screenshot_invalid_width_height_defaults(self, server_with_no_apps, monkeypatch):
async def test_handle_screenshot_renders_screen_state(self, server_with_no_apps, monkeypatch):
request = MagicMock()
request.query = {"route_key": "rk", "width": "nope", "height": "nope"}
request.query = {"route_key": "rk"}
request.headers = {}
# Mock screen state with some content
screen_buffer = [
[{"data": c, "fg": "default", "bg": "default", "bold": False, "italics": False, "underscore": False, "reverse": False} for c in "hello" + " " * 75],
[{"data": " ", "fg": "default", "bg": "default", "bold": False, "italics": False, "underscore": False, "reverse": False}] * 80,
]
session = MagicMock()
session.get_screen_lines = AsyncMock(return_value=["hello", ""])
session.get_replay_buffer = AsyncMock(return_value=b"hello\n")
session.get_screen_state = AsyncMock(return_value=(80, 2, screen_buffer))
monkeypatch.setattr(server_with_no_apps.session_manager, "get_session_by_route_key", lambda _rk: session)
resp = await server_with_no_apps._handle_screenshot(request)
@@ -736,15 +748,19 @@ class TestLocalServerMoreCoverage:
assert created is True
@pytest.mark.asyncio
async def test_handle_screenshot_uses_replay_buffer_with_pyte(self, server_with_no_apps, monkeypatch):
"""Test that screenshot uses replay buffer with pyte for colored rendering."""
async def test_handle_screenshot_uses_screen_state(self, server_with_no_apps, monkeypatch):
"""Test that screenshot uses get_screen_state for rendering."""
request = MagicMock()
request.query = {"route_key": "rk"}
request.headers = {}
# Mock screen state
screen_buffer = [
[{"data": c, "fg": "default", "bg": "default", "bold": False, "italics": False, "underscore": False, "reverse": False} for c in "line1" + " " * 75],
[{"data": c, "fg": "default", "bg": "default", "bold": False, "italics": False, "underscore": False, "reverse": False} for c in "line2" + " " * 75],
]
session = MagicMock()
session.get_screen_lines = AsyncMock(return_value=["line1", "line2", ""])
session.get_replay_buffer = AsyncMock(return_value=b"line1\r\nline2\r\n")
session.get_screen_state = AsyncMock(return_value=(80, 2, screen_buffer))
monkeypatch.setattr(server_with_no_apps.session_manager, "get_session_by_route_key", lambda _rk: session)
server_with_no_apps._route_last_activity["rk"] = 1.0
@@ -752,4 +768,4 @@ class TestLocalServerMoreCoverage:
resp = await server_with_no_apps._handle_screenshot(request)
assert resp.content_type == "image/svg+xml"
assert "<svg" in resp.text
session.get_replay_buffer.assert_awaited_once()
session.get_screen_state.assert_awaited_once()