pardes NEWFILE in a pane forwards even when its directory is missing, and Save makes the directories

fs.md said FILE must already exist, while `pardes new.txt` in fact
forwarded, making a pane named for it that Save creates. With a missing
directory (`pardes notes/new.txt`) the launch gave up forwarding and started
a nested editor inside the pane. Now the name is made absolute as written
and forwarded the same way. A name written to a pane's name file that goes
into a directory not there has its Save make the directories, as Config's
pane does. A Save <path> into a missing directory still fails ENOENT. The
Forwarding section now says what a new FILE does. fs.py launches one into a
missing directory and saves it.

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

1 files changed, 18 insertions, 0 deletions

diff --git a/src/ninep/pane.zig b/src/ninep/pane.zig
index de7f7cd4..6a0fbba5 100644
--- a/src/ninep/pane.zig
+++ b/src/ninep/pane.zig
@@ -867,6 +867,11 @@ fn writeName(p: *Pardes, req: Req, id: usize, pane: *Pane) Reply {
         error.OutOfMemory => E.NOMEM,
         else => E.INVAL,
     });
+    // A name into a directory not there yet asks for it, as Config's pane
+    // does: its Save makes the directories (`pardes new/dir/f` forwarded).
+    if (comptime pardes.hosted) if (fs.localPath(std.fs.path.dirname(full) orelse "/")) |local| {
+        if (!exec.isDirectory(local)) fileOf(pane).?.make_dirs = true;
+    };
     return .{ .tag = req.tag, .written = @intCast(req.data.len) };
 }
 
@@ -1387,6 +1392,19 @@ test "a name with a component over 255 bytes is refused, and a long path's faile
     try testing.expect(std.mem.endsWith(u8, late, "/f.txt: no such directory"));
 }
 
+test "a name into a directory not there has Save make it; one into a directory there does not" {
+    if (comptime !pardes.hosted) return error.SkipZigTest;
+    const p = try withFile(testing.allocator, "x\n");
+    defer p.deinit();
+    const serial = serialOf(p);
+    const f = fileOf(p.panes[p.paneBySerial(serial).?].?).?;
+    try testing.expectEqual(Status.ok, wr(p, Node.of(serial, .name), "/tmp/pardes-no-such-dir-mk/sub/f.txt\n").reply.status);
+    try testing.expect(f.make_dirs);
+    f.make_dirs = false;
+    try testing.expectEqual(Status.ok, wr(p, Node.of(serial, .name), "/tmp/f.txt\n").reply.status);
+    try testing.expect(!f.make_dirs);
+}
+
 test "a name cut across writes is one name, applied once at its newline or its close" {
     const p = try withFile(testing.allocator, "x\n");
     defer p.deinit();