A look at file:/re/ on an open pane goes on from its dot, and a miss leaves it

Look's clean start cleared the active pane's selection before the address
read the dot, so the root look's file:/re/ always found the same match, a
miss collapsed the dot to a caret, and dumps kept the collapsed dot. A pane
already open on the path is now addressed where it stands.

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

2 files changed, 26 insertions, 1 deletions

diff --git a/src/look.zig b/src/look.zig
index 542b1b63..9dfd912f 100644
--- a/src/look.zig
+++ b/src/look.zig
@@ -1237,7 +1237,15 @@ fn lookAddress(p: *Pardes, id: usize, path: []const u8, expr: []const u8) void {
     const ninep_pane = @import("ninep/pane.zig");
     const Addr = @import("ninep/addr.zig").Addr;
     var target = id;
-    if (path.len > 0) {
+    // A pane already open on the path is evaluated where it stands: Look's
+    // own clean start would collapse its dot (and the looker's) before the
+    // address ever read it, so `f:/re/` again would find the same match.
+    var realbuf: [4096]u8 = undefined;
+    const open: ?usize = if (path.len == 0) null else switch (resolveLookTarget(p, id, path, &realbuf)) {
+        .pane => |t| if (t.id < MAX_PANES and p.panes[t.id] != null) t.id else null,
+        else => null,
+    };
+    if (open) |o| target = o else if (path.len > 0) {
         const before = p.active;
         lookAt(p, id, path);
         target = p.active;
diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index 2fdc47cc..caa3f009 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -980,6 +980,23 @@ test "a look takes acme's :addr and file:addr, and a miss changes nothing" {
     try testing.expectStringStartsWith(p.panes[0].?.msg[0..p.panes[0].?.msg_len], "Look: ");
 }
 
+test "the root look's file:/re/ goes on from the dot, and a miss leaves the dot as it was" {
+    const gpa = testing.allocator;
+    const p = try withFile(gpa, "foo x foo y\nfoo\n");
+    defer p.deinit();
+    const dot = Node.of(serialOf(p), .dot);
+    const root = @intFromEnum(tree.TopFile.look);
+    var line: [256]u8 = undefined;
+    const path = p.panes[0].?.file.?.path;
+    const again = try std.fmt.bufPrint(&line, "{s}:/foo/\n", .{path});
+    for ([_][]const u8{ "          0           3 ", "          6           9 ", "         12          15 ", "          0           3 " }) |want| {
+        try testing.expectEqual(Status.ok, wr(p, root, again).reply.status);
+        try testing.expectEqualStrings(want, rd(p, dot, 0, 64).bytes);
+    }
+    try testing.expectEqual(Status.ok, wr(p, root, try std.fmt.bufPrint(&line, "{s}:/zzqq/\n", .{path})).reply.status);
+    try testing.expectEqualStrings("          0           3 ", rd(p, dot, 0, 64).bytes);
+}
+
 test "exec runs a builtin at the pane and records the pane it acted on" {
     const gpa = testing.allocator;
     const p = try withFile(gpa, "Msg fs-ran\n");