A Save that fails logs its err, not a save record

The save record was logged as soon as the host was asked to write, so a
Save into a read-only directory logged save and then failed. It is now
logged only once the write is done; a failure's err record (the write's,
naming the path) stands alone, the msg it was also said as dropped.

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

1 files changed, 29 insertions, 2 deletions

diff --git a/src/pardes.zig b/src/pardes.zig
index 5d709679..b488ec1c 100644
--- a/src/pardes.zig
+++ b/src/pardes.zig
@@ -5239,9 +5239,12 @@ pub const Pardes = struct {
                 p.hostWriteFile(sf.pane, f.path, f.content);
                 const saved_pane = p.panes[sf.pane] orelse return;
                 if (saved_pane.serial != serial) return;
-                ctlfs.events.noteLog(p, .save, saved_pane);
                 const saved = if (saved_pane.file) |*file| file else return;
-                if (saved.saved_revision != saved.revision or !saved.watch_after_save) return;
+                // A save the host could not do (saveFailed) is its err
+                // record alone, not a `save`.
+                if (saved.saved_revision != saved.revision) return;
+                ctlfs.events.noteLog(p, .save, saved_pane);
+                if (!saved.watch_after_save) return;
                 saved.watch_after_save = false;
                 if (filesystem.localPath(saved.path) != null)
                     p.emit(.{ .watch = .{ .pane = sf.pane, .on = true } });
@@ -7983,3 +7986,27 @@ test "a pane closed while its question stands ends the question in the log" {
     var want: [64]u8 = undefined;
     try std.testing.expect(th.logHas(p, try std.fmt.bufPrint(&want, "answer {d} -\ndel {d}", .{ serial, serial })));
 }
+
+test "a Save the host could not do logs no save record" {
+    const th = @import("ninep/testing.zig");
+    const p = try th.withFile(std.testing.allocator, "x\n");
+    defer p.deinit();
+    const Failing = struct {
+        core: *Pardes,
+        const vtable: Host.VTable = .{ .write_file = write };
+        fn write(ctx: ?*anyopaque, pane: u8, path: []const u8, _: []const u8) void {
+            const f: *@This() = @ptrCast(@alignCast(ctx.?));
+            f.core.saveFailed(pane, path, error.AccessDenied);
+        }
+    };
+    var host: Failing = .{ .core = p };
+    p.host = .{ .ctx = &host, .vtable = &Failing.vtable };
+    _ = th.wr(p, ctlfs.Node.of(p.panes[0].?.serial, .body), "more\n");
+    p.perform(.{ .save_file = .{ .pane = 0 } });
+    try std.testing.expect(!th.logHas(p, "\nsave "));
+    try std.testing.expect(p.panes[0].?.file.?.saved_revision != p.panes[0].?.file.?.revision);
+    // With the host's write done, it is logged.
+    p.host = .{};
+    p.perform(.{ .save_file = .{ .pane = 0 } });
+    try std.testing.expect(th.logHas(p, "\nsave "));
+}