new: Support excluding fields. (#74)

CHANGELOG.md

@@ -1,5 +1,14 @@
 # Changelog
 
+## Unreleased
+
+#### 🚀 Updates
+
+- Added an `exclude` attribute for `#[setting]` and `#[schema]` that excludes the field from the
+  generated schema.
+  - For `Schematic`, excludes from the schema.
+  - For `Config`, excludes from the schema, but is still required for the partial config.
+
 ## 0.12.1
 
 #### 🚀 Updates

crates/config/tests/macros_test.rs

@@ -37,6 +37,8 @@ pub struct ValueTypes {
     map: HashMap<String, u64>,
     enums: SomeEnum,
     s3_value: String,
+    #[setting(nested, exclude)]
+    other: OptionalValues,
 }
 
 #[derive(Config)]

crates/config/tests/schematic_enum_test.rs

@@ -9,6 +9,12 @@ pub enum SomeEnum {
     A,
     B,
     C,
+    #[schema(exclude)]
+    D,
+}
+
+pub struct NonSchematic {
+    string: String,
 }
 
 #[derive(Schematic)]
@@ -21,4 +27,7 @@ pub struct ValueTypes {
     map: HashMap<String, u64>,
     enums: SomeEnum,
     s3_value: String,
+
+    #[schema(exclude)]
+    other: NonSchematic,
 }

crates/macros/src/common/container.rs

@@ -35,7 +35,13 @@ impl<'l> Container<'l> {
             Self::NamedStruct { fields, .. } => {
                 let schema_types = fields
                     .iter()
-                    .map(|s| s.generate_schema_type(casing_format))
+                    .filter_map(|f| {
+                        if f.is_excluded() {
+                            None
+                        } else {
+                            Some(f.generate_schema_type(casing_format))
+                        }
+                    })
                     .collect::<Vec<_>>();
 
                 quote! {
@@ -55,7 +61,13 @@ impl<'l> Container<'l> {
             Self::Enum { variants } => {
                 let variants_types = variants
                     .iter()
-                    .map(|v| v.generate_schema_type(casing_format, &tagged_format))
+                    .filter_map(|v| {
+                        if v.is_excluded() {
+                            None
+                        } else {
+                            Some(v.generate_schema_type(casing_format, &tagged_format))
+                        }
+                    })
                     .collect::<Vec<_>>();
 
                 quote! {

crates/macros/src/common/field.rs

@@ -16,10 +16,12 @@ pub struct FieldSerdeArgs {
     pub skip: bool,
 }
 
-// #[field()], #[setting()]
+// #[schema()], #[setting()]
 #[derive(FromAttributes, Default)]
-#[darling(default, attributes(field, setting))]
+#[darling(default, attributes(schema, setting))]
 pub struct FieldArgs {
+    pub exclude: bool,
+
     // config
     #[darling(with = "preserve_str_literal", map = "Some")]
     pub default: Option<Expr>,
@@ -75,6 +77,10 @@ impl<'l> Field<'l> {
         field
     }
 
+    pub fn is_excluded(&self) -> bool {
+        self.args.exclude
+    }
+
     pub fn is_extendable(&self) -> bool {
         self.args.extend
     }

crates/macros/src/common/variant.rs

@@ -12,10 +12,11 @@ pub enum TaggedFormat {
     Adjacent(String, String),
 }
 
-// #[setting()], #[variant()]
+// #[setting()], #[schema()]
 #[derive(FromAttributes, Default)]
-#[darling(default, attributes(setting, variant))]
+#[darling(default, attributes(setting, schema))]
 pub struct VariantArgs {
+    pub exclude: bool,
     pub null: bool,
 
     // config
@@ -52,6 +53,10 @@ impl<'l> Variant<'l> {
         self.args.default
     }
 
+    pub fn is_excluded(&self) -> bool {
+        self.args.exclude
+    }
+
     pub fn is_nested(&self) -> bool {
         self.args.nested
     }

crates/macros/src/lib.rs

@@ -32,7 +32,7 @@ pub fn config_enum(item: TokenStream) -> TokenStream {
 
 // #[derive(Schematic)]
 #[cfg(feature = "schema")]
-#[proc_macro_derive(Schematic, attributes(schematic, field, variant))]
+#[proc_macro_derive(Schematic, attributes(schematic, schema))]
 pub fn schematic(item: TokenStream) -> TokenStream {
     let input: DeriveInput = parse_macro_input!(item);
     let output = schematic::SchematicMacro(Macro::from(&input));