feat: Make note of deprecated action optional

Author: Techassi

crates/stackable-versioned-macros/src/attrs/common/item.rs

@@ -143,20 +143,6 @@ impl ItemAttributes {
 
         let mut errors = Error::accumulator();
 
-        // TODO (@Techassi): Make the field or variant 'note' optional, because
-        // in the future, the macro will generate parts of the deprecation note
-        // automatically. The user-provided note will then be appended to the
-        // auto-generated one.
-
-        if let Some(deprecated) = &self.deprecated {
-            if deprecated.note.is_empty() {
-                errors.push(
-                    Error::custom("deprecation note must not be empty")
-                        .with_span(&deprecated.note.span()),
-                );
-            }
-        }
-
         // Semantic validation
         errors.handle(self.validate_action_combinations(item_ident, item_type));
         errors.handle(self.validate_action_order(item_ident, item_type));
@@ -348,9 +334,10 @@ pub(crate) struct ChangedAttributes {
 /// For the deprecated() action
 ///
 /// Example usage:
+/// - `deprecated(since = "...")`
 /// - `deprecated(since = "...", note = "...")`
 #[derive(Clone, Debug, FromMeta)]
 pub(crate) struct DeprecatedAttributes {
     pub(crate) since: SpannedValue<Version>,
-    pub(crate) note: SpannedValue<String>,
+    pub(crate) note: Option<SpannedValue<String>>,
 }

crates/stackable-versioned-macros/src/codegen/common/item.rs

@@ -148,7 +148,7 @@ where
                 ItemStatus::Deprecation {
                     previous_ident: ident.clone(),
                     ident: deprecated_ident.clone(),
-                    note: deprecated.note.to_string(),
+                    note: deprecated.note.as_deref().cloned(),
                 },
             );
 
@@ -363,8 +363,8 @@ pub(crate) enum ItemStatus {
     },
     Deprecation {
         previous_ident: Ident,
+        note: Option<String>,
         ident: Ident,
-        note: String,
     },
     NoChange(Ident),
     NotPresent,

crates/stackable-versioned-macros/src/codegen/venum/variant.rs

@@ -121,11 +121,27 @@ impl VersionedVariant {
                     #(#original_attributes)*
                     #to_ident,
                 }),
-                ItemStatus::Deprecation { ident, .. } => Some(quote! {
-                    #(#original_attributes)*
-                    #[deprecated]
-                    #ident,
-                }),
+                ItemStatus::Deprecation { ident, note, .. } => {
+                    // FIXME (@Techassi): Emitting the deprecated attribute
+                    // should cary over even when the item status is
+                    // 'NoChange'.
+                    // TODO (@Techassi): Make the generation of deprecated
+                    // items customizable. When a container is used as a K8s
+                    // CRD, the item must continue to exist, even when
+                    // deprecated. For other versioning use-cases, that
+                    // might not be the case.
+                    let deprecated_attr = if let Some(note) = note {
+                        quote! {#[deprecated = #note]}
+                    } else {
+                        quote! {#[deprecated]}
+                    };
+
+                    Some(quote! {
+                        #(#original_attributes)*
+                        #deprecated_attr
+                        #ident,
+                    })
+                }
                 ItemStatus::NoChange(ident) => Some(quote! {
                     #(#original_attributes)*
                     #ident,

crates/stackable-versioned-macros/src/codegen/vstruct/field.rs

@@ -135,11 +135,27 @@ impl VersionedField {
                         ident: field_ident,
                         note,
                         ..
-                    } => Some(quote! {
-                        #(#original_attributes)*
-                        #[deprecated = #note]
-                        pub #field_ident: #field_type,
-                    }),
+                    } => {
+                        // FIXME (@Techassi): Emitting the deprecated attribute
+                        // should cary over even when the item status is
+                        // 'NoChange'.
+                        // TODO (@Techassi): Make the generation of deprecated
+                        // items customizable. When a container is used as a K8s
+                        // CRD, the item must continue to exist, even when
+                        // deprecated. For other versioning use-cases, that
+                        // might not be the case.
+                        let deprecated_attr = if let Some(note) = note {
+                            quote! {#[deprecated = #note]}
+                        } else {
+                            quote! {#[deprecated]}
+                        };
+
+                        Some(quote! {
+                            #(#original_attributes)*
+                            #deprecated_attr
+                            pub #field_ident: #field_type,
+                        })
+                    }
                     ItemStatus::NotPresent => None,
                     ItemStatus::NoChange(field_ident) => Some(quote! {
                         #(#original_attributes)*