Add terminal push detection via OSC 11 and mode 2031 - #2
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lederniermagicien wants to merge 2 commits into
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Add terminal push detection via OSC 11 and mode 2031#2lederniermagicien wants to merge 2 commits into
lederniermagicien wants to merge 2 commits into
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Previously the extension relied solely on OS API polling (defaults/gsettings/reg)
to detect appearance changes. This works but is reactive only on each poll cycle.
Two new detection mechanisms are added on top of the existing polling fallback:
- On session start an OSC 11 background-colour query is sent to get an immediate
reading by deriving dark/light from the terminal's background luminance.
- Mode 2031 is enabled so the terminal can push a CSI ?997;{1|2}n notification
whenever its theme changes. Once a push notification is confirmed the polling
loop is stopped entirely for that session, and restarted if it wasn't.
COLORFGBG is also checked at the start of each sync cycle as a zero-cost
heuristic before spawning any OS subprocess.
notifyInfoIfUI and isSupportedPlatform are removed — the former was a thin
wrapper with one call site (inlined), the latter gated the entire extension on
three platforms. The extension now runs on all platforms; OS API detection simply
returns null on unsupported ones, leaving terminal-based detection still active.
Tests cover all new paths: COLORFGBG dark/light/priority/fallthrough, mode 2031
dark/light with debounce, polling suppression after push confirmed, OSC 11
dark/light, and MODE_2031_DISABLE on shutdown. TestContext gains onTerminalInput
and simulateTerminalInput; sessionShutdown is now also captured by the runtime
helper. README updated to reflect the two-tier detection model.
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What
Adds two terminal-native detection mechanisms on top of the existing OS API polling fallback.
OSC 11 query — on session start, the extension queries the terminal's background colour and derives dark/light from its luminance. This gives an immediate reading without waiting for the first poll cycle.
Mode 2031 push notifications — the extension enables
?2031hso the terminal can push aCSI ?997;{1|2}nsequence whenever its theme changes. Once a push is confirmed, the polling loop is stopped for the session. This makes theme switching instant and eliminates unnecessary subprocess spawning.COLORFGBG — checked at the start of every sync cycle as a zero-cost heuristic before spawning any OS process.
Why
Polling works but is inherently laggy and always spawns a subprocess. Terminals that support mode 2031 can push changes instantly; OSC 11 removes the delay on startup. Both mechanisms degrade gracefully — if the terminal doesn't respond, the extension falls back to polling as before.
Other changes
isSupportedPlatform()removed — the guard prevented terminal-based detection from running on unsupported platforms even though it doesn't depend on the OS. The extension now starts everywhere;detectAppearance()simply returnsnullon unknown platforms.notifyInfoIfUI()restored — it was dropped in the staged changes but is still referenced in the command handler.Tests
All new paths are covered: COLORFGBG (dark, light, 3-segment, priority over OS, invalid fallthrough), mode 2031 (dark, light, debounce, polling suppression after push confirmed), OSC 11 (dark, light), and
MODE_2031_DISABLEwritten on shutdown. 20 tests, all passing.