A restored terminal's tag names neither the REPL it was nor the shell it had

A dump keeps a terminal's whole tag, and restoring read its tail from it
after the directory: the REPL id and Tty+fish, which were live facts and not
the tag's text, came back as a custom tail, so the tags said python-a over a
fresh shell bound to nothing. Restoring now sees through the id and the
shell in the Tty word, a default tail stays the default, and the new shell
names itself when it starts.

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

2 files changed, 38 insertions, 1 deletions

diff --git a/src/pardes.zig b/src/pardes.zig
index f8328289..43d8e94d 100644
--- a/src/pardes.zig
+++ b/src/pardes.zig
@@ -1544,6 +1544,25 @@ test "a REPL bound for a language takes the exec made on a body in it; tags, Exe
     try std.testing.expect(doc.repl == null);
 }
 
+test "a restored terminal's tag names neither the REPL it was nor the shell it had" {
+    const gpa = std.testing.allocator;
+    const p = try Pardes.init(gpa, .{ .tty_only = true });
+    defer p.deinit();
+    while (p.nextEffect()) |_| {}
+    p.acknowledgeShell(0, "/usr/bin/fish", true);
+    var host: FakeTtyQuery = .{};
+    host.install(p);
+    try std.testing.expect(p.executeBuiltinLine(0, "Repl python"));
+    try dump.dumpState(p);
+    const restored = try dump.restore(p, p.dump_out.?, "test");
+    defer restored.deinit();
+    const pane = restored.panes[0].?;
+    try std.testing.expect(pane.repl == null and pane.tag.own == null);
+    const shown = try tagline.tagText(restored, restored.scratch.allocator(), pane);
+    try std.testing.expect(std.mem.indexOf(u8, shown, "python-a") == null);
+    try std.testing.expect(std.mem.indexOf(u8, shown, "Tty+fish") == null);
+}
+
 test "Tty+fish, one word a tag can hold, opens a terminal on that shell" {
     const p = try Pardes.init(std.testing.allocator, .{ .tty_only = true });
     defer p.deinit();
diff --git a/src/tagline.zig b/src/tagline.zig
index 28dffa06..6d5992f1 100644
--- a/src/tagline.zig
+++ b/src/tagline.zig
@@ -416,8 +416,26 @@ pub fn restoreTailAt(
         },
         .terminal => &.{ terminal_pane_tail, pre_close_last_terminal_pane_tail, pre_close_last_pane_tail, pre_mode_terminal_pane_tail, pre_tty_first_terminal_pane_tail, pre_collapse_terminal_pane_tail, pre_column_terminal_pane_tail, pre_tty_terminal_pane_tail, prev_terminal_pane_tail, legacy_terminal_pane_tail, pane_tail, pre_collapse_pane_tail, pre_column_pane_tail, prev_pane_tail, legacy_pane_tail },
     };
+    // A terminal's saved tag carries what was live about it -- the REPL id
+    // after its directory, the shell in its Tty word -- which is neither
+    // dumped nor true of the new shell: its tail is still the default.
+    var plain = said;
+    var plain_buf: [256]u8 = undefined;
+    if (class == .terminal) {
+        const first = plain[0 .. std.mem.indexOfScalar(u8, plain, ' ') orelse plain.len];
+        if (std.mem.lastIndexOfScalar(u8, first, '-')) |dash| if (dash + 2 == first.len and first[dash + 1] >= 'a' and first[dash + 1] <= 'z') {
+            for (@import("grammar_manifest.zig").all) |g| if (std.mem.eql(u8, g.name, first[0..dash])) {
+                plain = std.mem.trimStart(u8, plain[first.len..], " ");
+                break;
+            };
+        };
+        if (std.mem.startsWith(u8, plain, "Tty+")) {
+            const word_end = std.mem.indexOfScalar(u8, plain, ' ') orelse plain.len;
+            plain = std.fmt.bufPrint(&plain_buf, "Tty{s}", .{plain[word_end..]}) catch plain;
+        }
+    }
     for (defaults) |default|
-        if (std.mem.eql(u8, said, std.mem.trimStart(u8, default, " "))) return;
+        if (std.mem.eql(u8, plain, std.mem.trimStart(u8, default, " "))) return;
     pane.tag.own = p.gpa.dupe(u8, rest) catch return;
 }