nesquena-hermes
671f4504ae
Codex found the guard had a first-event gap: programmatic seeds of _lastScrollTop (_setMessageScrollToBottom, scrollToBottom, snapshot restore paths) didn't seed _lastMessageClientHeight, so the FIRST native toolbar-collapse scroll saw a null prior height -> grew=false -> the false-unpin still fired. Now every programmatic _lastScrollTop=el.scrollTop is paired with _lastMessageClientHeight=el.clientHeight.
62 lines
3.2 KiB
Python
62 lines
3.2 KiB
Python
"""Regression test for #4702 (sibling #4701).
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iOS Safari in PORTRAIT resolves its dynamic toolbar height *after* first paint.
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When the toolbar collapses, the #messages scroller grows (clientHeight increases),
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which fires a native scroll event with a DECREASED scrollTop even though the user
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never scrolled. Before the fix that reflow was misread as an upward scroll
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(`movedUp`), which falsely set `_messageUserUnpinned=true; _scrollPinned=false` on
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a freshly-opened session — stranding portrait readers at the top, and the late
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ResizeObserver settle then self-cancelled because of the false unpin.
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These are source-level guards (the runtime behavior is iOS-Safari-specific and not
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reproducible in CI), mirroring the static-assertion style of
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test_issue1360_streaming_scroll_hardening.py.
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"""
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import pathlib
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REPO = pathlib.Path(__file__).resolve().parent.parent
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UI_JS = (REPO / "static" / "ui.js").read_text(encoding="utf-8")
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def test_client_height_seeded_with_scrolltop_on_programmatic_writes():
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"""Every programmatic seed of `_lastScrollTop` must also seed
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`_lastMessageClientHeight`, else the FIRST native toolbar-collapse scroll event
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sees a null/stale prior height, `grew` is false, and the false-unpin still
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fires (Codex gate finding). The two must always be written together."""
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# No bare `_lastScrollTop=el.scrollTop;` without the height co-seed remains.
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assert "_lastScrollTop=el.scrollTop;\n" not in UI_JS, (
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"A programmatic _lastScrollTop=el.scrollTop write is missing the paired "
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"_lastMessageClientHeight=el.clientHeight seed (#4702)."
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)
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# The paired form is present at the programmatic-write sites.
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assert UI_JS.count("_lastScrollTop=el.scrollTop;_lastMessageClientHeight=el.clientHeight;") >= 4
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def test_client_height_growth_guard_declared():
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"""The scroller-height tracker must be declared so a toolbar-settle reflow can
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be distinguished from a real user scroll."""
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assert "let _lastMessageClientHeight=null;" in UI_JS
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def test_moved_up_ignores_container_growth():
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"""`movedUp` must be gated on `!grew` so a clientHeight increase (toolbar
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collapse) can't be misread as an upward user scroll (#4702)."""
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assert "const grew=_lastMessageClientHeight!==null&&el.clientHeight>_lastMessageClientHeight+1;" in UI_JS
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assert "const movedUp=!grew&&_lastScrollTop!==null&&top<_lastScrollTop-2;" in UI_JS
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# The height must be sampled every scroll event (so the next delta compares fresh).
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assert "_lastMessageClientHeight=el.clientHeight;" in UI_JS
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def test_client_height_tracker_reset_on_session_switch():
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"""A genuine session switch must reset the tracker so a stale cross-session
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height comparison can't suppress a real first scroll."""
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reset_idx = UI_JS.index("function _resetScrollDirectionTracker(){")
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body = UI_JS[reset_idx: reset_idx + 600]
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assert "_lastMessageClientHeight=null;" in body
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def test_explicit_settle_observes_scroller_for_portrait_toolbar():
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"""An explicit (open/user) settle must also observe the scroller itself, so a
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late portrait toolbar collapse re-anchors the bottom (#4702 defense-in-depth)."""
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assert "if(explicit&&observed!==el){ try{ ro.observe(el); }catch(_){ } }" in UI_JS
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