Mount with no dial is wrong #args, and a dial that is no address says bad dial address, both EINVAL

Mount name alone failed "Mount name dial: missing argument" and a
malformed dial "Mount: bad dial", both EIO, though each is a malformed
request. They now say wrong #args and bad dial address (with the forms
a dial takes), and a builtin failure in those words answers EINVAL, as
9ns reads them.

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

1 files changed, 8 insertions, 3 deletions

diff --git a/src/builtins.zig b/src/builtins.zig
index bc9bb075..89d89c3a 100644
--- a/src/builtins.zig
+++ b/src/builtins.zig
@@ -790,10 +790,15 @@ pub const Mount = struct {
     pub fn run(c: Ctx) void {
         if (comptime !enabled) unreachable;
         var args = std.mem.tokenizeAny(u8, c.arg orelse "", " \t");
-        const name = args.next() orelse return c.p.reportError(c.id, "Mount name dial", error.MissingArgument);
+        const e_args = "wrong #args in control message \"Mount\": Mount name dial";
+        const name = args.next() orelse return c.p.reportFailure(c.id, e_args);
         const dial = std.mem.trim(u8, args.rest(), " \t");
-        if (dial.len == 0) return c.p.reportError(c.id, "Mount name dial", error.MissingArgument);
-        c.p.fs.mount(c.p.gpa, name, dial) catch |err| return c.p.reportError(c.id, "Mount", err);
+        if (dial.len == 0) return c.p.reportFailure(c.id, e_args);
+        c.p.fs.mount(c.p.gpa, name, dial) catch |err| {
+            var said: [200]u8 = undefined;
+            if (err == error.BadDial) return c.p.reportFailure(c.id, std.fmt.bufPrint(&said, "Mount: bad dial address: {s} (unix!/path, tcp!host!port, or a session name)", .{dial[0..@min(dial.len, 100)]}) catch "Mount: bad dial address");
+            return c.p.reportError(c.id, "Mount", err);
+        };
         // A mount that cannot be reached is said now, and taken back, not
         // found out by the first look through it.
         const reached = reached: {