A failed Dump or a Restore of no dump fails its write, before any warning

A Dump into a DumpDir it could not write, or a Restore of a file that is
not a dump, answered a ctl write with rc 0 and only a message, and the
Restore warned about unsaved panes before it ever looked at the file. The
hosts' dump write now fails the waiting 9P write with EIO (the late failure
a Save uses), naming the path and the reason in the log, and Restore parses
the file before its unsaved-panes refusal, failing with `not a pardes
dump`.

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

1 files changed, 14 insertions, 0 deletions

diff --git a/src/pardes.zig b/src/pardes.zig
index 452f6174..c2bde804 100644
--- a/src/pardes.zig
+++ b/src/pardes.zig
@@ -5105,6 +5105,20 @@ pub const Pardes = struct {
         p.fs.late_failure_len = @intCast(kept.len);
     }
 
+    /// A Dump the host could not write: said on the message row and in the
+    /// log, and the 9P write that asked for it fails with it, as a failed
+    /// Save's does.
+    pub fn dumpFailed(p: *Pardes, path: []const u8, err: anyerror) void {
+        var what: [limits.host_path_cap + 8]u8 = undefined;
+        const operation = std.fmt.bufPrint(&what, "Dump {s}", .{path}) catch "Dump";
+        p.reportError(p.active, operation, err);
+        var buf: [256]u8 = undefined;
+        const said = std.fmt.bufPrint(&buf, "{s}: {s}", .{ operation, @errorName(err) }) catch "Dump failed";
+        const kept = @import("Messages.zig").clip(said, p.fs.late_failure.len);
+        @memcpy(p.fs.late_failure[0..kept.len], kept);
+        p.fs.late_failure_len = @intCast(kept.len);
+    }
+
     /// The path a watch is about: a real file's, or a PDF's.
     fn watchPath(p: *const Pardes, id: u8) ?[]const u8 {
         const pane = p.panes[id] orelse return null;