From 210b5efe125dce3eeaff87fd7c7ee2ad13e7b118 Mon Sep 17 00:00:00 2001
From: Robert Bastian <robertbastian@google.com>
Date: Tue, 27 Jun 2023 18:12:52 +0200
Subject: [PATCH] recommended

---
 provider/datagen/src/bin/datagen/args.rs | 11 +++++++----
 provider/datagen/src/lib.rs              | 10 ++++++++++
 provider/datagen/src/options.rs          |  5 +++++
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/provider/datagen/src/bin/datagen/args.rs b/provider/datagen/src/bin/datagen/args.rs
index 87c241ddd39..4bed51b00d1 100644
--- a/provider/datagen/src/bin/datagen/args.rs
+++ b/provider/datagen/src/bin/datagen/args.rs
@@ -78,8 +78,8 @@ impl CollationTable {
 #[command(about = format!("Learn more at: https://docs.rs/icu_datagen/{}", option_env!("CARGO_PKG_VERSION").unwrap_or("")), long_about = None)]
 #[command(group(
             ArgGroup::new("key_mode")
-                // .required(true)
-                .args(["keys", "key_file", "keys_for_bin", "all_keys"]),
+                .required(true)
+                .args(["keys", "key_file", "keys_for_bin", "all_keys", "config"]),
         ))]
 pub struct Cli {
     #[arg(short, long)]
@@ -202,10 +202,11 @@ pub struct Cli {
     #[arg(help = "Deprecated: alias for --keys all")]
     all_keys: bool,
 
-    #[arg(long, short, num_args = 0..)]
+    #[arg(long, short, num_args = 0.., default_value = "recommended")]
     #[arg(
         help = "Include this locale in the output. Accepts multiple arguments. \
-                  Set to 'full' or 'modern' for the respective CLDR locale sets, or 'none' for no locales."
+                  Set to 'full' or 'modern' for the respective CLDR locale sets, 'none' for no locales, \
+                  or 'recommended' for the recommended set of locales."
     )]
     locales: Vec<String>,
 
@@ -325,6 +326,8 @@ impl Cli {
     fn make_locales(&self) -> eyre::Result<config::LocaleInclude> {
         Ok(if self.locales.as_slice() == ["none"] {
             config::LocaleInclude::None
+        } else if self.locales.as_slice() == ["recommended"] {
+            config::LocaleInclude::Recommended
         } else if self.locales.as_slice() == ["full"] || self.all_locales {
             config::LocaleInclude::All
         } else if let Some(locale_subsets) = self
diff --git a/provider/datagen/src/lib.rs b/provider/datagen/src/lib.rs
index 017e7925d03..624c588dc16 100644
--- a/provider/datagen/src/lib.rs
+++ b/provider/datagen/src/lib.rs
@@ -165,6 +165,16 @@ impl DatagenProvider {
             ),
             options::LocaleInclude::Explicit(set) => options::LocaleInclude::Explicit(set),
             options::LocaleInclude::All => options::LocaleInclude::All,
+            options::LocaleInclude::Recommended => options::LocaleInclude::Explicit(
+                source
+                    .locales(&[
+                        CoverageLevel::Modern,
+                        CoverageLevel::Moderate,
+                        CoverageLevel::Basic,
+                    ])?
+                    .into_iter()
+                    .collect(),
+            ),
         };
 
         if source.options.fallback == options::FallbackMode::Runtime {
diff --git a/provider/datagen/src/options.rs b/provider/datagen/src/options.rs
index ab5a2d3e122..640c2df6e4e 100644
--- a/provider/datagen/src/options.rs
+++ b/provider/datagen/src/options.rs
@@ -71,6 +71,11 @@ pub enum LocaleInclude {
     Explicit(HashSet<LanguageIdentifier>),
     /// All locales with the given CLDR coverage levels
     CldrSet(HashSet<CoverageLevel>),
+    /// A recommended set of locales.
+    ///
+    /// This currently resolves to `CldrSet({Modern, Moderate, Basic}) but
+    /// might change in future releases.
+    Recommended,
 }
 
 impl Default for LocaleInclude {