« Installez textual pour le TUI (pip) » left the user to work out which pip,
which interpreter, which package — and it was printed from eight different
places. Every TUI screen now asks:
⚠ Textual est nécessaire pour cet écran.
L'installer maintenant ? (O/n, défaut : oui)
The command targets sys.executable, the interpreter that will have to import
it — installing a distribution package would land somewhere the venv never
looks. Outside a venv it adds --user, which is also what gets past the refusal
of distributions whose environment is externally managed (PEP 668).
Two details that decide whether this works at all:
· importlib.invalidate_caches() after installing. A failed import is
remembered, so without it textual stays « missing » for the rest of the
session despite having just been installed.
· a pip that exits non-zero never reports success. The check is « is it
importable NOW », not « did pip return 0 », and the failure suggests the
distribution package by name.
It lives in its own module rather than as a TODO method: todo_upgrade needs it
too and is imported BY todo, so putting it there would close a cycle.
One call site is deliberately NOT converted. The statistics screen only reads
files; it never touches Textual, and its old message claimed otherwise. An
import failure there is a real module problem and now says so.
Verified: already-present asks nothing and runs nothing; refusal installs
nothing; pip failing returns False and points at python3-textual; pip
succeeding returns True; prompt=False reports without asking. Then each of the
four TUI entries — telemetry, deploy form, deploy progress, migration resume —
offers and falls back cleanly on refusal, while the statistics screen stays
silent.
Also caught by those tests: « import importlib » alone does not expose
importlib.util, so availability could not be checked at all.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
