Refactor config types into a separate crate (#16962)

Move config types into a separate crate because their macros expand into
a lot of new code.

codex-rs/config/src/schema.rs

@@ -0,0 +1,100 @@
+use crate::config_toml::ConfigToml;
+use crate::types::RawMcpServerConfig;
+use codex_features::FEATURES;
+use codex_features::legacy_feature_keys;
+use schemars::r#gen::SchemaGenerator;
+use schemars::r#gen::SchemaSettings;
+use schemars::schema::InstanceType;
+use schemars::schema::ObjectValidation;
+use schemars::schema::RootSchema;
+use schemars::schema::Schema;
+use schemars::schema::SchemaObject;
+use serde_json::Map;
+use serde_json::Value;
+use std::path::Path;
+
+/// Schema for the `[features]` map with known + legacy keys only.
+pub fn features_schema(schema_gen: &mut SchemaGenerator) -> Schema {
+    let mut object = SchemaObject {
+        instance_type: Some(InstanceType::Object.into()),
+        ..Default::default()
+    };
+
+    let mut validation = ObjectValidation::default();
+    for feature in FEATURES {
+        if feature.id == codex_features::Feature::Artifact {
+            continue;
+        }
+        validation
+            .properties
+            .insert(feature.key.to_string(), schema_gen.subschema_for::<bool>());
+    }
+    for legacy_key in legacy_feature_keys() {
+        validation
+            .properties
+            .insert(legacy_key.to_string(), schema_gen.subschema_for::<bool>());
+    }
+    validation.additional_properties = Some(Box::new(Schema::Bool(false)));
+    object.object = Some(Box::new(validation));
+
+    Schema::Object(object)
+}
+
+/// Schema for the `[mcp_servers]` map using the raw input shape.
+pub fn mcp_servers_schema(schema_gen: &mut SchemaGenerator) -> Schema {
+    let mut object = SchemaObject {
+        instance_type: Some(InstanceType::Object.into()),
+        ..Default::default()
+    };
+
+    let validation = ObjectValidation {
+        additional_properties: Some(Box::new(schema_gen.subschema_for::<RawMcpServerConfig>())),
+        ..Default::default()
+    };
+    object.object = Some(Box::new(validation));
+
+    Schema::Object(object)
+}
+
+/// Build the config schema for `config.toml`.
+pub fn config_schema() -> RootSchema {
+    SchemaSettings::draft07()
+        .with(|settings| {
+            settings.option_add_null_type = false;
+        })
+        .into_generator()
+        .into_root_schema_for::<ConfigToml>()
+}
+
+/// Canonicalize a JSON value by sorting its keys.
+pub fn canonicalize(value: &Value) -> Value {
+    match value {
+        Value::Array(items) => Value::Array(items.iter().map(canonicalize).collect()),
+        Value::Object(map) => {
+            let mut entries: Vec<_> = map.iter().collect();
+            entries.sort_by(|(left, _), (right, _)| left.cmp(right));
+            let mut sorted = Map::with_capacity(map.len());
+            for (key, child) in entries {
+                sorted.insert(key.clone(), canonicalize(child));
+            }
+            Value::Object(sorted)
+        }
+        _ => value.clone(),
+    }
+}
+
+/// Render the config schema as pretty-printed JSON.
+pub fn config_schema_json() -> anyhow::Result<Vec<u8>> {
+    let schema = config_schema();
+    let value = serde_json::to_value(schema)?;
+    let value = canonicalize(&value);
+    let json = serde_json::to_vec_pretty(&value)?;
+    Ok(json)
+}
+
+/// Write the config schema fixture to disk.
+pub fn write_config_schema(out_path: &Path) -> anyhow::Result<()> {
+    let json = config_schema_json()?;
+    std::fs::write(out_path, json)?;
+    Ok(())
+}