Shell refuses a name that is no executable, and bare restores the default

Shell took any word and the host quietly ran another shell at the next
spawn. It now refuses a path or name that is not executable ("Shell: x:
no executable by that name", failing a ctl write, logged err), a bare
Shell goes back to the default, and a default $SHELL that is not
executable falls back to /bin/sh. shellset's golden takes the refusal on
the message row (re-recorded by name).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 6 insertions, 1 deletions

diff --git a/docs/config.md b/docs/config.md
index 93190556..95f034d7 100644
--- a/docs/config.md
+++ b/docs/config.md
@@ -47,7 +47,12 @@ The startup path is printed whether or not a file exists — that is usually whe
 it is most useful — and is ordinary selectable text, so a right click on it
 opens the file. Shell follows the same requested/effective/pending model as
 Font. `Default shell` is the one used while no `Shell` is set: `$SHELL`, the
-user's login shell, else `/bin/sh`; an explicit `Shell` overrides it. `Shell
+user's login shell, else `/bin/sh` (also when `$SHELL` names nothing
+executable); an explicit `Shell` overrides it. `Shell <name or path>` is
+refused, `Shell: <it>: no executable by that name`, unless it names an
+executable (a bare name is looked for in the usual bin directories), and a
+bare `Shell` goes back to the default. The root ctl reads `Shell <the one the
+next terminal runs>`. `Shell
 effective (last spawn)` is the executable the native host really chose after
 installation lookup and fallback. A changed request remains pending until a
 terminal is spawned, because the core does not resolve native executables.