An a, c or i text with no . line fails the Edit, as an open { does

sam takes the end of input as a text block's end, so a block cut short (a
write that lost its tail, an open closed early) inserted half of itself.
An Edit whose a, c or i text never meets its . line now fails with "a, c
or i text not ended by a . line" and changes nothing, as an unclosed {
does; at a close, logged as an err.

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

1 files changed, 11 insertions, 0 deletions

diff --git a/src/ninep/tree.zig b/src/ninep/tree.zig
index 398824d5..54d21da6 100644
--- a/src/ninep/tree.zig
+++ b/src/ninep/tree.zig
@@ -1536,3 +1536,14 @@ test "an Edit block still open when its open closes fails there with an err and
     try testing.expect(th.logHas(p, "unmatched"));
     try testing.expectEqualStrings("abc\n", p.panes[0].?.file.?.content);
 }
+
+test "an a, c or i text still open when its open closes fails there too and changes nothing" {
+    const p = try th.withFile(testing.allocator, "abc\n");
+    defer p.deinit();
+    const ctl_node = Node.of(serialOf(p), .ctl);
+    const c = call(p, .{ .tag = 1, .op = .open, .node = ctl_node, .omode = 1 }).reply.handle;
+    _ = call(p, .{ .tag = 2, .op = .write, .node = ctl_node, .handle = c, .data = "Edit $a\nhalf of a block\n" });
+    _ = call(p, .{ .tag = 3, .op = .release, .node = ctl_node, .handle = c, .opened = true });
+    try testing.expect(th.logHas(p, "not ended by a . line"));
+    try testing.expectEqualStrings("abc\n", p.panes[0].?.file.?.content);
+}