Zerox twins survive a Dump and Restore: their text is dumped once, in the first, each other twin names it (twin_of), and Restore puts them back on one buffer with their dots

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

1 files changed, 25 insertions, 1 deletions

diff --git a/src/dump.zig b/src/dump.zig
index b64441d3..1ded9989 100644
--- a/src/dump.zig
+++ b/src/dump.zig
@@ -232,6 +232,9 @@ pub const File = struct {
     /// Its dot, q0 and q1 in bytes, as acme's dump keeps a window's; null
     /// in older dumps.
     dot: ?[2]u32 = null,
+    /// A Zerox twin: the index, in `panes`, of the earlier pane whose
+    /// buffer it shares, its text kept there once; null for none.
+    twin_of: ?u32 = null,
 };
 
 pub const ImagePalette = enum {
@@ -767,6 +770,22 @@ pub fn dumpState(p: *Pardes) !void {
         dump_panes[panes_len] = dp;
         panes_len += 1;
     }
+    // Zerox's twins: the text once, in the first; each other names it.
+    for (p.panes, 0..) |slot, id| {
+        const f = (slot orelse continue).file orelse continue;
+        if (f.twin == 0) continue;
+        const i = slot_to_pane[id] orelse continue;
+        for (p.panes[0..id], 0..) |earlier, j_id| {
+            const of = (earlier orelse continue).file orelse continue;
+            if (of.twin != f.twin) continue;
+            const j = slot_to_pane[j_id] orelse break;
+            if (dump_panes[i].file) |*df| {
+                df.twin_of = @intCast(j);
+                df.content_b64 = "";
+            }
+            break;
+        }
+    }
 
     var columns: [MAX_COLS]Column = undefined;
     var columns_len: usize = 0;
@@ -963,7 +982,12 @@ fn initDump(gpa: std.mem.Allocator, opts: Options, zon_bytes: []const u8, previo
                 if (t.petscii and pardes.panes.terminal.petscii(restored) == false) pardes.panes.terminal.togglePetscii(restored);
                 break :terminal restored;
             },
-            .file => try pardes.panes.File.restore(p, i, src),
+            .file => file: {
+                const restored = try pardes.panes.File.restore(p, i, src);
+                // A twin: on the earlier pane's buffer again.
+                if (src.file.?.twin_of) |j| if (j < i) pardes.panes.File.relink(p, j, i, src.file.?.dot);
+                break :file restored;
+            },
             .image => restore_image: {
                 const im = src.image.?;
                 if (pardes.panes.Pdf.isPath(im.path)) {