Nested headless Hyprland aborts on Wayland host protocol version announcements #90

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opened 2026-10-11 13:15:19 +08:00 by Breadway · 2 comments

Breadway commented

2026-10-11 13:15:19 +08:00

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Found while testing ECO-71 in an entirely isolated headless environment. Confidence: high for the observed failure; root cause in package/protocol interface compatibility is unconfirmed. On the installed Hyprland 0.56.2 / Aquamarine 0.15.1 stack, a private Weston 15.0.1 headless GL host causes invalid version for global wl_compositor (1): expected at most 5, got 6, followed by CBackend::create failure. An isolated Sway headless host instead fails on xdg_wm_base (13): expected at most 5, got 6. No live desktop operations are required to reproduce. Investigate whether the packaged client binds an advertised version newer than its compiled interface, or whether linked protocol symbols disagree. This blocks straightforward headless nested testing. A test-only proxy that caps these registry announcements is being evaluated as a workaround.

Found while testing ECO-71 in an entirely isolated headless environment. Confidence: high for the observed failure; root cause in package/protocol interface compatibility is unconfirmed. On the installed Hyprland 0.56.2 / Aquamarine 0.15.1 stack, a private Weston 15.0.1 headless GL host causes `invalid version for global wl_compositor (1): expected at most 5, got 6`, followed by CBackend::create failure. An isolated Sway headless host instead fails on `xdg_wm_base (13): expected at most 5, got 6`. No live desktop operations are required to reproduce. Investigate whether the packaged client binds an advertised version newer than its compiled interface, or whether linked protocol symbols disagree. This blocks straightforward headless nested testing. A test-only proxy that caps these registry announcements is being evaluated as a workaround.

Breadway commented

2026-10-11 13:57:47 +08:00

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ECO-71 handoff update: the workaround is now implemented and used successfully by bread-session/tests/wayland_compat.py. It forwards Unix-socket traffic and SCM_RIGHTS file descriptors while capping wl_compositor and xdg_wm_base versions to 5 in both registry announcements and outgoing registry.bind requests. This is test-only Python; the deployed session app is Rust. A private headless Weston GL host plus this proxy and a separate Hyprland headless output passed 12 session integration checks and the later breadbar old/new comparison. It does not resolve the underlying packaged protocol mismatch, whose root cause remains unconfirmed. Keep this issue open for the package-level investigation. See ECO-71 for isolation safeguards and retained evidence.

Breadway commented

2026-10-20 15:27:17 +08:00

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Triage (no change made, card left in todo).

Searched Breadway/bos (scripts/, iso/, docs/) for the named harness (wayland_compat, weston, sway headless, headless). No headless or nested-compositor harness exists in this repo. The workaround the card describes lives in bread-session/tests/wayland_compat.py, which is outside this repo.

Reproducing or fixing the root cause (packaged wl_compositor / xdg_wm_base version mismatch between Aquamarine 0.15.1 and the host protocol) needs a live or private headless compositor and a package-level investigation. I did not start either, and nothing was changed. Leaving in todo for the package-level investigation.

Triage (no change made, card left in todo). Searched Breadway/bos (scripts/, iso/, docs/) for the named harness (wayland_compat, weston, sway headless, headless). No headless or nested-compositor harness exists in this repo. The workaround the card describes lives in bread-session/tests/wayland_compat.py, which is outside this repo. Reproducing or fixing the root cause (packaged wl_compositor / xdg_wm_base version mismatch between Aquamarine 0.15.1 and the host protocol) needs a live or private headless compositor and a package-level investigation. I did not start either, and nothing was changed. Leaving in todo for the package-level investigation.