Every setting's bad-value refusal names what it takes: InactiveDim 0-100, MessageLinger 0-60000 milliseconds, a path's limit, a font's form

A setting that chooses among words named them, but one that takes a
number, a path or a font said only "bad value" over 9P and "does not
take that value" from a tag, leaving the range to be guessed. The
refusal, both ways, now says its range or what it takes, from one
table beside the words.

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

4 files changed, 29 insertions, 7 deletions

diff --git a/src/Messages.zig b/src/Messages.zig
index 3eeb8c92..a316377a 100644
--- a/src/Messages.zig
+++ b/src/Messages.zig
@@ -876,7 +876,7 @@ test "a builtin announces itself on the message row, and Verbose silences it" {
     // A value it does not take is said, in place of the announcement.
     const wrapped = p.settings.wrap;
     try std.testing.expect(p.executeBuiltinLine(p.active, "Wrap maybe"));
-    try std.testing.expectEqualStrings("Wrap: takes on or off", pane.msg[0..pane.msg_len]);
+    try std.testing.expectEqualStrings("Wrap: takes on, off", pane.msg[0..pane.msg_len]);
     try std.testing.expectEqual(wrapped, p.settings.wrap);
 
     // The notice list is what the paint pass reads, so the announcement has to
diff --git a/src/config.zig b/src/config.zig
index a7377cfa..a17e2fd2 100644
--- a/src/config.zig
+++ b/src/config.zig
@@ -1242,6 +1242,22 @@ pub const Runtime = struct {
         };
     }
 
+    /// What a setting takes, for a refusal of a bad value to name: its
+    /// words (`choices`), else its range or the kind of thing it takes.
+    pub fn takes(action: Action) ?[]const u8 {
+        return choices(action) orelse switch (action) {
+            .inactive_dim, .window_opacity, .window_blur => "0-100 (a percentage)",
+            .grip_width => "50-300 (a percentage)",
+            .tagline_size => std.fmt.comptimePrint("{d}-{d} (a percentage)", .{ tagline_percent_min, tagline_percent_max }),
+            .message_ms => std.fmt.comptimePrint("0-{d} (milliseconds)", .{message_ms_max}),
+            .shell => "a path of at most 255 bytes; bare, the login shell",
+            .dump_dir => std.fmt.comptimePrint("a path of at most {d} bytes; bare, the default", .{limits.host_path_cap}),
+            .shader => "a Shadertoy file's path, or off",
+            .font => "a name or path, :8 to :72 after it (Mono:14)",
+            else => null,
+        };
+    }
+
     /// The value a choice word names, or bare, the one after `now`; null for
     /// a word it does not take.
     fn stepped(comptime T: type, now: T, argument: ?[]const u8) ?T {
diff --git a/src/exec.zig b/src/exec.zig
index 215a4fd1..c673aab2 100644
--- a/src/exec.zig
+++ b/src/exec.zig
@@ -1015,12 +1015,13 @@ pub fn applySettingBuiltin(p: *Pardes, setting: config.Runtime.Setting, arg: ?[]
                     return p.reportFailure(p.active, std.fmt.bufPrint(&text, "Shell: {s}", .{refused}) catch "Shell: no such shell");
                 }
             }
-            if (!p.settings.apply(setting, want) and p.announce) p.reportFailure(p.active, "Shell: does not take that value");
+            if (!p.settings.apply(setting, want) and p.announce) p.reportFailure(p.active, "Shell: takes " ++ comptime config.Runtime.takes(.shell).?);
         },
+        // Said with what it takes: its words, its range.
         else => if (!p.settings.apply(setting, arg) and p.announce) {
-            var text: [96]u8 = undefined;
-            const takes = if (setting.action == .toggle) "takes on or off" else "does not take that value";
-            p.reportFailure(p.active, std.fmt.bufPrint(&text, "{s}: {s}", .{ setting.word, takes }) catch takes);
+            var text: [160]u8 = undefined;
+            const why = if (config.Runtime.takes(setting.action)) |values| std.fmt.bufPrint(&text, "{s}: takes {s}", .{ setting.word, values }) else std.fmt.bufPrint(&text, "{s}: does not take that value", .{setting.word});
+            p.reportFailure(p.active, why catch "does not take that value");
         },
     }
     if (p.settings.colors != previous_colors) {
diff --git a/src/ninep/ctl.zig b/src/ninep/ctl.zig
index 27361124..2cd865de 100644
--- a/src/ninep/ctl.zig
+++ b/src/ninep/ctl.zig
@@ -491,8 +491,8 @@ fn checkBuiltin(p: *Pardes, req: Req, line: []const u8, scope: builtins.Scope) ?
         },
     };
     if (takes) return null;
-    var why: [104]u8 = undefined;
-    return refuse(p, req, if (config.Runtime.choices(setting.action)) |values|
+    var why: [160]u8 = undefined;
+    return refuse(p, req, if (config.Runtime.takes(setting.action)) |values|
         std.fmt.bufPrint(&why, "bad value in control message; takes {s}", .{values}) catch "bad value in control message"
     else
         "bad value in control message", line);
@@ -1256,6 +1256,11 @@ test "the root ctl reads the settings as a write takes them, and takes the sessi
     try testing.expectEqualStrings("unknown control message \"Nonsense 1\"", wr(p, root_ctl, "Nonsense 1").reply.ename);
     try testing.expectEqualStrings("bad value in control message; takes on, off \"Verbose maybe\"", wr(p, root_ctl, "Verbose maybe").reply.ename);
     try testing.expectEqualStrings("bad value in control message; takes acme, pardes \"Placement east\"", wr(p, root_ctl, "Placement east").reply.ename);
+    // A number's refusal names its range, a path's what it takes.
+    try testing.expectEqualStrings("bad value in control message; takes 0-100 (a percentage) \"InactiveDim 200\"", wr(p, root_ctl, "InactiveDim 200").reply.ename);
+    try testing.expectEqualStrings("bad value in control message; takes 0-60000 (milliseconds) \"MessageLinger x\"", wr(p, root_ctl, "MessageLinger x").reply.ename);
+    for (config.Runtime.settings) |setting| if (setting.action != .theme)
+        try testing.expect(config.Runtime.takes(setting.action) != null);
     const no_theme = wr(p, root_ctl, "Theme no-such-theme").reply.ename;
     try testing.expectStringStartsWith(no_theme, "bad value in control message; like it: n");
     try testing.expect(std.mem.endsWith(u8, no_theme, "; Themes lists all \"Theme no-such-theme\""));