The classic Windows console renders through GDI with the console font and no
emoji font behind it, so every icon in the menu came up as a replacement box.
It is what a double-clicked build gets, which is most of the Windows audience.
The fix already existed: the compact single-character glyph table built for the
PicoCalc, reached by Platform.emoji. The seam's flags are independent, so
clearing that one alone keeps the desktop's width, colour and accented names and
moves only the icons — without_emoji() is the whole change to the platform.
Identifying the host has to be structural. It cannot be asked in band, because a
missing glyph still fills its cell: a classic console stores an emoji intact and
advances two cells while showing a box, and a ConPTY reads back as U+FFFD while
drawing it perfectly, so a write-and-read-back probe answers both hosts
backwards. Nor can the environment answer, since WT_SESSION is inherited across
process launches. So two independent facts must agree — the console font has a
real pixel width (a ConPTY's hidden conhost reports zero) and the buffer is
taller than its window (a ConPTY has no scrollback of its own) — and an unknown
never degrades anything. MESHTERM_EMOJI overrides either way, and
`meshterm platform` reports the verdict and its reason.
Verified on Windows 10 22H2 in all three: a real conhost turns the icons
compact, Windows Terminal keeps its emoji, a redirected run is left alone.
_has_wide_glyph asked the same flag to mean "nothing here is two cells wide",
which was true of the PicoCalc's fixed font rather than of the flag. A console
that merely lacks emoji still renders the rest of the BMP, and a contact named
in CJK is two cells wide there like anywhere else, so it now asks ascii_fold —
the fold is what actually guarantees it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Jean-Pierre MartineauandClaude Opus 5
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