swayfx-mosaic/tooling/probes/step20c-negative-origin/README.md

STEP20C negative-origin nested-grab fixture (EXPERIMENTAL)

This source-only fixture rebuilds the pinned private compositor and SceneFX through the historical nested-grab fixture, then applies only the historical parameterized pointer patch to a disposable client copy. The original nested client supplies two real XDG grabs and horizontal placements. No production source, installed library or historical fixture is modified. The probe report contains the coordinate contract and evidence.

Pinned inputs

Input	Base	SHA-256
SceneFX private patch	SceneFX 37ccd723bef49e6891156ffafce8f549f01446cc	c74c515b98da8f5f637e260e6a3755c7a75bd78d1c39e54a67850f1c383e30e7
Mosaic private patch	Mosaic cd550382b311efdbfe3ed892f4e1d281d852e754	d416f6413ea097a48a44d231e50ffba363914f46c8687f0ea2e4dcacd5f31fe9
Hidden-owner guard	After Mosaic private patch	35785a8f3e863b3c1fd87932d8ff0c2949b03cb04382cc34e1126170968f802b
nested-client.c	Original nested fixture	2e40c98af72a0df8b316810589a0be8f4425a763db1de448b49a7813956b6f7d
pointer-daemon.c	Original valid-grab fixture, then patch below	a00fcedc38ccb7ca4c25c982d9f38e8bde3168a3833f0c9cf2056e841d720938
pointer-extents.patch	Original vertical fixture	4eeb9f808d0941edca82dc3c5d24a9c936cc3d9d8bb80af3db6aed6af0d47c50

The new prepare.sh (ed9d0e8bf50338d39519e003463e637cdba3ecfb147e05a097e88ac6c8def694), run.py (7b9e2d311dcf942e4dc625b8fcc25c650b7c3ec1f604828397cf1de120b43541), analyze.py (2d33f4876ea1e982b32f9e73145db86836ba2fa7f5382f9433b4b9f076098a49) and patched pointer source (ede9a39adbe1744c771a784f6ad0c296259e36b942c78d75be620b86b9f2a66d) can be rechecked against the source manifest in each laboratory. The three private patches, nested client and pointer patch remain byte-identical to their historical versions. No new SceneFX, Mosaic or client patch is needed for this geometry; all changes are in the new runner and wrapper.

Fresh preparation and replay

Run from a full Git checkout containing the pinned commits. Dependencies are those listed in the linked historical fixture: Git, Meson, Ninja, C17 compiler, pkg-config, wayland-scanner, kitty, grim, wev, swaymsg, Python and the documented development libraries. prepare.sh creates a new temporary laboratory, checks and applies private patches there, builds SceneFX/Mosaic privately, generates protocol bindings and compiles the two clients. It prints LAB and BUILD_LOG; retain both paths. analyze.py additionally needs Pillow to decode the retained PNG captures.

prep=$(sh tooling/probes/step20c-negative-origin/prepare.sh)
printf '%s\n' "$prep"
LAB=$(printf '%s\n' "$prep" | sed -n 's/^LAB=//p')
test -d "$LAB"
for mode in control private_standard private_mosaic; do
  python tooling/probes/step20c-negative-origin/run.py "$LAB" "$mode" pointer negative
  python tooling/probes/step20c-negative-origin/run.py "$LAB" "$mode" visible negative
  python tooling/probes/step20c-negative-origin/run.py "$LAB" "$mode" b_cross negative
  python tooling/probes/step20c-negative-origin/run.py "$LAB" "$mode" both_cross negative
  python tooling/probes/step20c-negative-origin/run.py "$LAB" "$mode" a_cross negative
  python tooling/probes/step20c-negative-origin/run.py "$LAB" "$mode" outside negative
done
for scenario in hidden hidden_click toggle; do
  python tooling/probes/step20c-negative-origin/run.py "$LAB" private_mosaic "$scenario" negative
done
for mode in control private_standard private_mosaic; do
  python tooling/probes/step20c-negative-origin/run.py "$LAB" "$mode" b_cross positive
done
PYTHONDONTWRITEBYTECODE=1 python tooling/probes/step20c-negative-origin/analyze.py "$LAB"

Each invocation creates a single-use run-GEOMETRY-CASE-SCENARIO directory under LAB. Retain a failed case by renaming its directory before retrying. The runner writes outputs-verified.json, injections.json, pointer-validation.json, measurements.json for popup scenarios, IPC tree and output snapshots, WAYLAND_DEBUG=1 client trace, wev, pointer and compositor logs, captures of both outputs, and exit-status.json. The coordinate conversion is sent_x=global_x-min_x after IPC confirms the negative layout bounds; the absolute extent is 1600×600. Inspect client events as well as pointer acknowledgements. A control popup crossing is conclusive only if actual pixels and buttons cross the border.

Each case uses a short, private mode-0700 /tmp/mno-* runtime and an explicit discovered SWAYSOCK for every swaymsg -s call. WAYLAND_DISPLAY is private. The runner removes its own runtime only after reaping its process groups and writing exit codes. Private SceneFX is loaded only for the private compositor. The current desktop and ordinary Sway IPC socket are never addressed.

Checks and cleanup

sh -n tooling/probes/step20c-negative-origin/prepare.sh
PYTHONDONTWRITEBYTECODE=1 python -c 'import ast; ast.parse(open("tooling/probes/step20c-negative-origin/run.py").read())'
(cd "$LAB" && sha256sum -c negative-origin-source-sha256.txt)
git diff --check

Review measurements and hash evidence before removing the named LAB and BUILD_LOG. Generated protocol sources, binaries, captures, logs and sockets remain outside Git. Cleanup must target only paths printed by this probe; historical laboratories and the active session are outside its ownership.