* fix(tui): keep welcome banner at top after /new
PR #262 replaced scroll_end() with anchor() for free-scrolling.
When /new clears a long anchored conversation, the anchor kept
the viewport pinned to the (now empty) bottom, producing a
negative scroll_y and pushing the welcome banner out of view.
Reset the anchor and scroll to the top in clear_chat(), and
restore the follow/new-content flags so the fresh session starts
correctly.
Closes#301
* fix(tui): suppress anchor when chat content fits viewport
The previous fix for #301 only handled the /new path. din0s reported
that the banner still dropped to the bottom after a normal short turn
(user types 'hi', agent replies) — i.e. whenever the conversation
fit in the viewport. Root cause is in Textual's compositor
(textual._compositor): when a widget is anchored, scroll_y is
recomputed via set_reactive, which bypasses the validator. If the
anchored widget's content is shorter than the viewport, scroll_y
goes negative on the next layout pass and the welcome banner is
pushed below the visible region.
PR #262 made _stream_with_widgets re-engage the anchor at the end of
every turn via _anchor_chat, so the bug surfaced on any short reply
that fit in the viewport. Markdown re-renders, status-bar updates,
or any subsequent mount would then trip the compositor.
Fix in three places:
* _anchor_chat: only engage the anchor when max_scroll_y > 0;
otherwise release and scroll_home so the banner stays at the top.
* streaming anchor loop: if content shrinks below the viewport
mid-stream (e.g. loading widget removed), release the anchor
instead of leaving _anchored=True for the compositor to trip on.
* clear_chat: keep the unconditional reset (children are removed
asynchronously so a max_scroll_y check would be stale) but
document why.
Adds two regressions:
* test_short_turn_keeps_banner_at_top_after_layout_refresh — the
exact scenario din0s tested; fails with scroll_y=-10 on the
previous code, passes with the fix.
* test_long_turn_keeps_viewport_pinned_to_bottom — guards against
regressing free-scrolling for overflowing conversations.
Manually verified: 'hi' -> reply (banner stays at top) -> /new
(banner at top) -> another turn (banner stays at top).
* test(tui): address review feedback on banner-position regressions
- extract `_release_anchor_and_pin_top` helper for the 3-line
`anchor(False) + scroll_home(...)` pattern repeated in
`clear_chat`, `_anchor_chat`, and the streaming loop
- replace `pytest.skip` in `_capture_app` with a hard `RuntimeError`
so a broken capture never silently passes
- drop the redundant `load_agent` and `create_session_workspace`
monkeypatches (the factory is given those as parameters, so the
module-level symbols never run; added a comment explaining why)
- add a defensive `_FakeChannelRuntime` patch for symmetry with the
other module-level fakes
- drop the local `_run` helper and use the `run_async` fixture from
`conftest.py` (its teardown is better)
* test(tui): replace _FakeChannelRuntime with _auto_start_channel no-op
The _FakeChannelRuntime patch was ineffective because ChannelRuntime is
just a dataclass — the real channel manager still started via
_auto_start_channel, leaving pending tasks and non-hermetic test state.
Per review feedback, stub _auto_start_channel directly instead.
houren Antony
7568a6bc1f