A pane whose whole text fits in its rows never scrolls to keep a margin

The scroll margin reveals text; with none off screen there is nothing to
reveal. ensureCursorVisible and a centred look both leave such a pane at its
top. A longer file keeps helix's clamp (hxdiff and hxparity unchanged).

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

1 files changed, 18 insertions, 0 deletions

diff --git a/src/pardes.zig b/src/pardes.zig
index 23341904..18eedccb 100644
--- a/src/pardes.zig
+++ b/src/pardes.zig
@@ -1354,6 +1354,24 @@ test "BootShell keep leaves the untouched boot shell a dragged document joins; r
     }
 }
 
+test "a pane its whole text fits in never scrolls to keep a margin" {
+    const p = try Pardes.init(std.testing.allocator, .{ .tty_only = true, .cols = 80, .rows = 30 });
+    defer p.deinit();
+    const pane = try p.setTestFile("one\ntwo\nthree\n");
+    // A second pane under it, as acme's placement puts one: right under the
+    // three lines, which leaves the file exactly three body rows.
+    const below = p.freeSlot().?;
+    _ = try p.openTutorView(below);
+    exec.placeNew(p, 0, 0, below, .doc);
+    p.active = 0;
+    p.sync();
+    try std.testing.expectEqual(@as(u16, 3), p.rects[0].h - pane.tag_rows);
+    for ("jj") |c| p.update(.{ .key = .{ .cp = c, .text = &.{c} } });
+    p.sync();
+    try std.testing.expectEqual(@as(i32, 2), pane.body.cur_row);
+    try std.testing.expectEqual(@as(i32, 0), pane.scroll());
+}
+
 test "dragging a column's only pane to another leaves that column in place, empty" {
     const p = try Pardes.init(std.testing.allocator, .{ .tty_only = true, .cols = 160, .rows = 32 });
     defer p.deinit();