Add #[serde(rename_all_fields = "foo")] attribute

serde_derive/src/internals/ast.rs

@@ -88,9 +88,12 @@ impl<'a> Container<'a> {
                         if field.attrs.flatten() {
                             has_flatten = true;
                         }
-                        field
-                            .attrs
-                            .rename_by_rules(variant.attrs.rename_all_rules());
+                        field.attrs.rename_by_rules(
+                            &variant
+                                .attrs
+                                .rename_all_rules()
+                                .or(attrs.rename_all_fields_rules()),
+                        );
                     }
                 }
             }

serde_derive/src/internals/attr.rs

@@ -193,11 +193,23 @@ impl Name {
     }
 }
 
+#[derive(Copy, Clone)]
 pub struct RenameAllRules {
     serialize: RenameRule,
     deserialize: RenameRule,
 }
 
+impl RenameAllRules {
+    /// Returns a new `RenameAllRules` with the individual rules of `self` and
+    /// `other_rules` joined by `RenameRules::or`.
+    pub fn or(&self, other_rules: &Self) -> Self {
+        Self {
+            serialize: self.serialize.or(&other_rules.serialize),
+            deserialize: self.deserialize.or(&other_rules.deserialize),
+        }
+    }
+}
+
 /// Represents struct or enum attribute information.
 pub struct Container {
     name: Name,
@@ -205,6 +217,7 @@ pub struct Container {
     deny_unknown_fields: bool,
     default: Default,
     rename_all_rules: RenameAllRules,
+    rename_all_fields_rules: RenameAllRules,
     ser_bound: Option<Vec<syn::WherePredicate>>,
     de_bound: Option<Vec<syn::WherePredicate>>,
     tag: TagType,
@@ -288,6 +301,8 @@ impl Container {
         let mut default = Attr::none(cx, DEFAULT);
         let mut rename_all_ser_rule = Attr::none(cx, RENAME_ALL);
         let mut rename_all_de_rule = Attr::none(cx, RENAME_ALL);
+        let mut rename_all_fields_ser_rule = Attr::none(cx, RENAME_ALL_FIELDS);
+        let mut rename_all_fields_de_rule = Attr::none(cx, RENAME_ALL_FIELDS);
         let mut ser_bound = Attr::none(cx, BOUND);
         let mut de_bound = Attr::none(cx, BOUND);
         let mut untagged = BoolAttr::none(cx, UNTAGGED);
@@ -341,6 +356,44 @@ impl Container {
                             }
                         }
                     }
+                } else if meta.path == RENAME_ALL_FIELDS {
+                    // #[serde(rename_all_fields = "foo")]
+                    // #[serde(rename_all_fields(serialize = "foo", deserialize = "bar"))]
+                    let one_name = meta.input.peek(Token![=]);
+                    let (ser, de) = get_renames(cx, RENAME_ALL_FIELDS, &meta)?;
+
+                    match item.data {
+                        syn::Data::Enum(_) => {
+                            if let Some(ser) = ser {
+                                match RenameRule::from_str(&ser.value()) {
+                                    Ok(rename_rule) => {
+                                        rename_all_fields_ser_rule.set(&meta.path, rename_rule);
+                                    }
+                                    Err(err) => cx.error_spanned_by(ser, err),
+                                }
+                            }
+                            if let Some(de) = de {
+                                match RenameRule::from_str(&de.value()) {
+                                    Ok(rename_rule) => {
+                                        rename_all_fields_de_rule.set(&meta.path, rename_rule);
+                                    }
+                                    Err(err) => {
+                                        if !one_name {
+                                            cx.error_spanned_by(de, err);
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                        syn::Data::Struct(_) => {
+                            let msg = "#[serde(rename_all_fields)] can only be used on enums";
+                            cx.error_spanned_by(&meta.path, msg);
+                        }
+                        syn::Data::Union(_) => {
+                            let msg = "#[serde(rename_all_fields)] can only be used on enums";
+                            cx.error_spanned_by(&meta.path, msg);
+                        }
+                    }
                 } else if meta.path == TRANSPARENT {
                     // #[serde(transparent)]
                     transparent.set_true(meta.path);
@@ -528,6 +581,10 @@ impl Container {
                 serialize: rename_all_ser_rule.get().unwrap_or(RenameRule::None),
                 deserialize: rename_all_de_rule.get().unwrap_or(RenameRule::None),
             },
+            rename_all_fields_rules: RenameAllRules {
+                serialize: rename_all_fields_ser_rule.get().unwrap_or(RenameRule::None),
+                deserialize: rename_all_fields_de_rule.get().unwrap_or(RenameRule::None),
+            },
             ser_bound: ser_bound.get(),
             de_bound: de_bound.get(),
             tag: decide_tag(cx, item, untagged, internal_tag, content),
@@ -551,6 +608,10 @@ impl Container {
         &self.rename_all_rules
     }
 
+    pub fn rename_all_fields_rules(&self) -> &RenameAllRules {
+        &self.rename_all_fields_rules
+    }
+
     pub fn transparent(&self) -> bool {
         self.transparent
     }

serde_derive/src/internals/case.rs

@@ -112,6 +112,14 @@ impl RenameRule {
             ScreamingKebabCase => ScreamingSnakeCase.apply_to_field(field).replace('_', "-"),
         }
     }
+
+    /// Returns the `RenameRule` if it is not `None`, `rule_b` otherwise.
+    pub fn or(&self, rule_b: &Self) -> Self {
+        match self {
+            None => *rule_b,
+            _ => *self,
+        }
+    }
 }
 
 pub struct ParseError<'a> {

serde_derive/src/internals/symbol.rs

@@ -23,6 +23,7 @@ pub const OTHER: Symbol = Symbol("other");
 pub const REMOTE: Symbol = Symbol("remote");
 pub const RENAME: Symbol = Symbol("rename");
 pub const RENAME_ALL: Symbol = Symbol("rename_all");
+pub const RENAME_ALL_FIELDS: Symbol = Symbol("rename_all_fields");
 pub const REPR: Symbol = Symbol("repr");
 pub const SERDE: Symbol = Symbol("serde");
 pub const SERIALIZE: Symbol = Symbol("serialize");