A terminal's Tty word names its shell, Tty+fish, and a click on it opens another

A terminal's tag said Tty whatever shell it ran. The host's acknowledgement
of the shell it forked now sets the word to Tty+<shell>, tinted like the tag's
name. Word+arg is taken as Word arg, one word a tag can hold and a click can
take whole (+ is a word character), so Tty+fish opens a terminal on fish, as
Tty fish does; Tty takes the shell as its argument, which the host forks for
that pane instead of the configured one. Every snapshot whose screen shows a
terminal's tag changes: 69 goldens, re-recorded by name, whose 297 changed
lines are all Tty becoming Tty+bash (the harness runs bash), the cursor
columns and style spans that moved with it, or that text cut at a pane's
width.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/src/exec.zig b/src/exec.zig
index 07d5e92f..e2b9f880 100644
--- a/src/exec.zig
+++ b/src/exec.zig
@@ -488,7 +488,8 @@ pub fn commandText(txt: []const u8) []const u8 {
 pub fn executeBuiltinLine(p: *Pardes, id: usize, txt: []const u8) bool {
     const cmd = commandText(txt);
     if (cmd.len == 0 or p.exec_depth >= max_exec_depth) return false;
-    const sp = std.mem.indexOfAny(u8, cmd, " \t");
+    // `Word arg`, or as one word a tag can hold, `Word+arg` (`Tty+fish`).
+    const sp = std.mem.indexOfAny(u8, cmd, " \t") orelse std.mem.indexOfScalar(u8, cmd, '+');
     const bi: ?Builtin = std.meta.stringToEnum(Builtin, cmd) orelse blk: {
         const head = std.meta.stringToEnum(Builtin, cmd[0 .. sp orelse break :blk null]) orelse break :blk null;
         break :blk if (builtins.registry.takesArg(head)) head else null;