A shell's > on addr no longer resets it, so echo /re/ > addr searches on

Truncating addr reset it to #0, so a shell's find-and-replace loop matched the first hit for ever, .+#1 read 1 1 each time, and foo x foo y foo became foobarbarbar... acme resets addr on the first open (xfid.c:105-108), for clients that hold the fid; a shell cannot. Here neither an open nor a truncation resets it: the address written is evaluated from the last one, and 0 or , starts over. Documented as a departure from acme.

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

1 files changed, 23 insertions, 2 deletions

diff --git a/src/ninep/addr.zig b/src/ninep/addr.zig
index 0537c17a..ccb08924 100644
--- a/src/ninep/addr.zig
+++ b/src/ninep/addr.zig
@@ -340,13 +340,34 @@ test "a failed address leaves none, so data refuses rather than act at the last
     try testing.expectEqualStrings(pane_files.e_addr_failed, th.rd(p, addr, 0, 64).reply.ename);
     try testing.expectEqual(E.INVAL, th.call(p, .{ .tag = 1, .op = .setattr, .node = Node.of(serial, .xdata), .truncate = true }).errno());
     try testing.expectEqualStrings("one\ntwo\n", p.panes[0].?.file.?.content);
-    // A good address, or a truncated addr, gives it one again.
+    // A good address gives it one again; truncating addr does not.
     _ = th.wr(p, addr, "#0,#3");
     try testing.expectEqual(Status.ok, th.wr(p, data, "ONE").reply.status);
     try testing.expectEqualStrings("ONE\ntwo\n", p.panes[0].?.file.?.content);
     _ = th.wr(p, addr, "99");
     _ = th.call(p, .{ .tag = 1, .op = .setattr, .node = addr, .truncate = true });
-    try testing.expectEqual(Status.ok, th.wr(p, data, "0").reply.status);
+    try testing.expectEqualStrings(pane_files.e_addr_failed, th.wr(p, data, "0").reply.ename);
+}
+
+test "a shell's > on addr searches on from the last address, and 0 starts over" {
+    const p = try th.withFile(testing.allocator, "foo x foo y foo\n");
+    defer p.deinit();
+    const serial = th.serialOf(p);
+    const addr = Node.of(serial, .addr);
+    const data = Node.of(serial, .data);
+    // echo /foo/ > addr; printf foobar > data -- twice over, as a loop does.
+    for (0..3) |_| {
+        _ = th.call(p, .{ .tag = 1, .op = .setattr, .node = addr, .truncate = true });
+        try testing.expectEqual(Status.ok, th.wr(p, addr, "/foo/").reply.status);
+        _ = th.call(p, .{ .tag = 1, .op = .setattr, .node = data, .truncate = true });
+        try testing.expectEqual(Status.ok, th.wr(p, data, "foobar").reply.status);
+    }
+    try testing.expectEqualStrings("foobar x foobar y foobar\n", p.panes[0].?.file.?.content);
+    // .+#1 moves on from where the last write left the address.
+    _ = th.wr(p, addr, "0");
+    _ = th.call(p, .{ .tag = 1, .op = .setattr, .node = addr, .truncate = true });
+    try testing.expectEqual(Status.ok, th.wr(p, addr, ".+#1").reply.status);
+    try testing.expectEqualStrings("          1           1 ", th.rd(p, addr, 0, 64).bytes);
 }
 
 test "the address language, form by form" {