A name shows its own backslash as \\, and a terminal tag never carries a raw newline

With `\n` for a newline and `\xNN` for a bad byte, a name holding a
backslash and an n read back as one holding a newline. Names in /index,
the log and a terminal's tag now double their own backslashes; and a
terminal's directory with a newline no longer breaks its tag.

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

1 files changed, 16 insertions, 5 deletions

diff --git a/src/tagline.zig b/src/tagline.zig
index d024be4e..5f95b2a0 100644
--- a/src/tagline.zig
+++ b/src/tagline.zig
@@ -112,6 +112,17 @@ pub fn revealHeader(p: *Pardes) void {
     }
 }
 
+/// A terminal's directory as its tag shows it: one line, as /index shows
+/// it (a newline `\n`), never a raw newline breaking the tag.
+fn shownDir(arena: std.mem.Allocator, pane: *Pane) ![]const u8 {
+    const dir = pane.cwdSlice();
+    if (std.mem.indexOfAny(u8, dir, "\n\\\x7f") == null and for (dir) |c| {
+        if (c < ' ') break false;
+    } else true) return dir;
+    const out = try arena.alloc(u8, dir.len * 4 + 4);
+    return pardes.ctlfs.events.shown(dir, out);
+}
+
 /// The computed start of a pane's tag -- its path and dirty marker, a
 /// PDF's page, a terminal's directory -- without the space that parts it
 /// from the tag's own text. It is never stored, and never edited.
@@ -133,19 +144,19 @@ pub fn pathPrefix(arena: std.mem.Allocator, pane: *Pane) ![]const u8 {
         var idbuf: [48]u8 = undefined;
         const id = exec.replId(&idbuf, pane);
         const gap = if (id.len > 0) " " else "";
-        if (!pane.command_done) return std.fmt.allocPrint(arena, "{s} ({s}{s}) running{s}{s}", .{ pane.cwdSlice(), shown, more, gap, id });
-        if (pane.command_status) |n| return std.fmt.allocPrint(arena, "{s} ({s}{s}) exit {d}{s}{s}", .{ pane.cwdSlice(), shown, more, n, gap, id });
-        return std.fmt.allocPrint(arena, "{s} ({s}{s}) exit ?{s}{s}", .{ pane.cwdSlice(), shown, more, gap, id });
+        if (!pane.command_done) return std.fmt.allocPrint(arena, "{s} ({s}{s}) running{s}{s}", .{ (try shownDir(arena, pane)), shown, more, gap, id });
+        if (pane.command_status) |n| return std.fmt.allocPrint(arena, "{s} ({s}{s}) exit {d}{s}{s}", .{ (try shownDir(arena, pane)), shown, more, n, gap, id });
+        return std.fmt.allocPrint(arena, "{s} ({s}{s}) exit ?{s}{s}", .{ (try shownDir(arena, pane)), shown, more, gap, id });
     }
     // A bound REPL says what it is bound as, beside its Tty word.
     if (pane.repl != null) {
         var idbuf: [48]u8 = undefined;
-        return std.fmt.allocPrint(arena, "{s} {s}", .{ pane.cwdSlice(), exec.replId(&idbuf, pane) });
+        return std.fmt.allocPrint(arena, "{s} {s}", .{ (try shownDir(arena, pane)), exec.replId(&idbuf, pane) });
     }
     // Unsaved text shows on the grip, as acme's modbutton does, not as a
     // mark in the text: the prefix is the name alone.
     if (pane.file) |f| return if (pane.prompt == .name) pane.input.own orelse f.path else f.path;
-    return pane.cwdSlice();
+    return (try shownDir(arena, pane));
 }
 
 pub fn tagPrefix(p: *Pardes, pane: *Pane) ![]u8 {