deprecate config option skip_children

Author: scampi

Configurations.md

@@ -1881,7 +1881,7 @@ specific version of rustfmt is used in your CI, use this option.
 - **Possible values**: any published version (e.g. `"0.3.8"`)
 - **Stable**: No (tracking issue: #3386)
 
-## `skip_children`
+## `skip_children` (DEPRECATED #3587)
 
 Don't reformat out of line modules
 

src/config/config_type.rs

@@ -58,6 +58,9 @@ macro_rules! create_config {
 
         use serde::{Deserialize, Serialize};
 
+        // for error messages
+        use ansi_term::Colour::Red;
+
         #[derive(Clone)]
         #[allow(unreachable_pub)]
         pub struct Config {
@@ -137,8 +140,16 @@ macro_rules! create_config {
             }
 
             fn fill_from_parsed_config(mut self, parsed: PartialConfig, dir: &Path) -> Config {
+                let deprecate_skip_children = || {
+                    let msg = "Option skip_children is deprecated since it is now the default to not format submodules of given files (#3587)";
+                    eprintln!("{}: {}", Red.bold().paint("Deprecation"), msg);
+                };
+
             $(
                 if let Some(val) = parsed.$i {
+                    if stringify!($i) == "skip_children" {
+                        deprecate_skip_children()
+                    }
                     if self.$i.3 {
                         self.$i.1 = true;
                         self.$i.2 = val;
@@ -216,6 +227,7 @@ macro_rules! create_config {
                 match key {
                     $(
                         stringify!($i) => {
+                dbg!(stringify!($i));
                             self.$i.1 = true;
                             self.$i.2 = val.parse::<$ty>()
                                 .expect(&format!("Failed to parse override for {} (\"{}\") as a {}",