Add #[rustfmt::sort] for struct structs

src/expr.rs

@@ -1684,6 +1684,7 @@ fn rewrite_struct_lit<'a>(
             v_shape,
             mk_sp(body_lo, span.hi()),
             one_line_width,
+            None,
         )
         .unknown_error()?
     } else {

src/items.rs

@@ -2,7 +2,7 @@
 
 use itertools::Itertools;
 use regex::Regex;
-use rustc_ast::{AttrVec, visit};
+use rustc_ast::visit;
 use rustc_ast::{ast, ptr};
 use rustc_span::{BytePos, DUMMY_SP, Span, symbol};
 use std::borrow::Cow;
@@ -519,13 +519,19 @@ impl<'a> FmtVisitor<'a> {
         self.push_rewrite(static_parts.span, rewrite);
     }
 
-    pub(crate) fn visit_struct(&mut self, struct_parts: &StructParts<'_>) {
+    pub(crate) fn visit_struct(&mut self, struct_parts: &StructParts<'_>, sort: bool) {
         let is_tuple = match struct_parts.def {
             ast::VariantData::Tuple(..) => true,
             _ => false,
         };
-        let rewrite = format_struct(&self.get_context(), struct_parts, self.block_indent, None)
-            .map(|s| if is_tuple { s + ";" } else { s });
+        let rewrite = format_struct(
+            &self.get_context(),
+            struct_parts,
+            self.block_indent,
+            None,
+            sort,
+        )
+        .map(|s| if is_tuple { s + ";" } else { s });
         self.push_rewrite(struct_parts.span, rewrite);
     }
 
@@ -705,6 +711,7 @@ impl<'a> FmtVisitor<'a> {
                 &StructParts::from_variant(field, &context),
                 self.block_indent,
                 Some(one_line_width),
+                false,
             )?,
             ast::VariantData::Unit(..) => rewrite_ident(&context, field.ident).to_owned(),
         };
@@ -1153,14 +1160,15 @@ fn format_struct(
     struct_parts: &StructParts<'_>,
     offset: Indent,
     one_line_width: Option<usize>,
+    sort: bool,
 ) -> Option<String> {
     match struct_parts.def {
         ast::VariantData::Unit(..) => format_unit_struct(context, struct_parts, offset),
         ast::VariantData::Tuple(fields, _) => {
             format_tuple_struct(context, struct_parts, fields, offset)
         }
         ast::VariantData::Struct { fields, .. } => {
-            format_struct_struct(context, struct_parts, fields, offset, one_line_width)
+            format_struct_struct(context, struct_parts, fields, offset, one_line_width, sort)
         }
     }
 }
@@ -1439,6 +1447,7 @@ pub(crate) fn format_struct_struct(
     fields: &[ast::FieldDef],
     offset: Indent,
     one_line_width: Option<usize>,
+    sort: bool,
 ) -> Option<String> {
     let mut result = String::with_capacity(1024);
     let span = struct_parts.span;
@@ -1507,12 +1516,36 @@ pub(crate) fn format_struct_struct(
     let one_line_budget =
         one_line_width.map_or(0, |one_line_width| min(one_line_width, one_line_budget));
 
+    let ranks: Option<Vec<_>> = if sort {
+        // get the sequence of indices that would sort the vec
+        let indices: Vec<usize> = fields
+            .iter()
+            .enumerate()
+            .sorted_by(|(_, field_a), (_, field_b)| {
+                field_a
+                    .ident
+                    .zip(field_b.ident)
+                    .map(|(a, b)| a.name.as_str().cmp(b.name.as_str()))
+                    .unwrap_or(Ordering::Equal)
+            })
+            .map(|(i, _)| i)
+            .collect();
+        // create a vec with ranks for the fields, allowing for use in Itertools.sorted_by_key
+        let mut ranks = vec![0; indices.len()];
+        for (rank, original_index) in indices.into_iter().enumerate() {
+            ranks[original_index] = rank;
+        }
+        Some(ranks)
+    } else {
+        None
+    };
     let items_str = rewrite_with_alignment(
         fields,
         context,
         Shape::indented(offset.block_indent(context.config), context.config).sub_width(1)?,
         mk_sp(body_lo, span.hi()),
         one_line_budget,
+        ranks.as_ref().map(|v| v.as_slice()),
     )?;
 
     if !items_str.contains('\n')

src/vertical.rs

@@ -114,6 +114,7 @@ pub(crate) fn rewrite_with_alignment<T: AlignedItem>(
     shape: Shape,
     span: Span,
     one_line_width: usize,
+    ranks: Option<&[usize]>,
 ) -> Option<String> {
     let (spaces, group_index) = if context.config.struct_field_align_threshold() > 0 {
         group_aligned_items(context, fields)
@@ -170,12 +171,20 @@ pub(crate) fn rewrite_with_alignment<T: AlignedItem>(
         shape.indent,
         one_line_width,
         force_separator,
+        ranks.map(|v| &v[0..=group_index]),
     )?;
     if rest.is_empty() {
         Some(result + spaces)
     } else {
         let rest_span = mk_sp(init_last_pos, span.hi());
-        let rest_str = rewrite_with_alignment(rest, context, shape, rest_span, one_line_width)?;
+        let rest_str = rewrite_with_alignment(
+            rest,
+            context,
+            shape,
+            rest_span,
+            one_line_width,
+            ranks.map(|v| &v[group_index + 1..]),
+        )?;
         Some(format!(
             "{}{}\n{}{}",
             result,
@@ -211,6 +220,7 @@ fn rewrite_aligned_items_inner<T: AlignedItem>(
     offset: Indent,
     one_line_width: usize,
     force_trailing_separator: bool,
+    ranks: Option<&[usize]>,
 ) -> Option<String> {
     // 1 = ","
     let item_shape = Shape::indented(offset, context.config).sub_width(1)?;
@@ -266,6 +276,14 @@ fn rewrite_aligned_items_inner<T: AlignedItem>(
         .tactic(tactic)
         .trailing_separator(separator_tactic)
         .preserve_newline(true);
+    if let Some(ranks) = ranks {
+        items = ranks
+            .iter()
+            .zip(items.into_iter())
+            .sorted_by_key(|&(index, _)| *index)
+            .map(|(_, item)| item)
+            .collect();
+    }
     write_list(&items, &fmt).ok()
 }
 

src/visitor.rs

@@ -23,8 +23,9 @@ use crate::source_map::{LineRangeUtils, SpanUtils};
 use crate::spanned::Spanned;
 use crate::stmt::Stmt;
 use crate::utils::{
-    self, contains_skip, count_newlines, depr_skip_annotation, format_safety, inner_attributes,
-    last_line_width, mk_sp, ptr_vec_to_ref_vec, rewrite_ident, starts_with_newline, stmt_expr,
+    self, contains_skip, contains_sort, count_newlines, depr_skip_annotation, format_safety,
+    inner_attributes, last_line_width, mk_sp, ptr_vec_to_ref_vec, rewrite_ident,
+    starts_with_newline, stmt_expr,
 };
 use crate::{ErrorKind, FormatReport, FormattingError};
 
@@ -511,7 +512,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
                     self.push_rewrite(span, rw);
                 }
                 ast::ItemKind::Struct(..) | ast::ItemKind::Union(..) => {
-                    self.visit_struct(&StructParts::from_item(item));
+                    self.visit_struct(&StructParts::from_item(item), contains_sort(&item.attrs));
                 }
                 ast::ItemKind::Enum(ref def, ref generics) => {
                     self.format_missing_with_indent(source!(self, item.span).lo());

tests/source/structs.rs

@@ -296,3 +296,24 @@ struct Test {
 // #2818
 struct Paren((i32)) where i32: Trait;
 struct Parens((i32, i32)) where i32: Trait;
+
+// #3422
+#[rustfmt::sort]
+struct Foo {
+
+    #[skip]
+    b: u32,
+    a: u32, // a
+
+    bb: u32,
+    /// A
+    aa: u32,
+}
+
+#[rustfmt::sort]
+struct Fooy {
+    a: u32, // a
+    b: u32,
+    /// C
+    c: u32,
+}

tests/target/structs.rs

@@ -356,3 +356,23 @@ where
 struct Parens((i32, i32))
 where
     i32: Trait;
+
+// #3422
+#[rustfmt::sort]
+struct Foo {
+    a: u32, // a
+
+    /// A
+    aa: u32,
+    #[skip]
+    b: u32,
+    bb: u32,
+}
+
+#[rustfmt::sort]
+struct Fooy {
+    a: u32, // a
+    b: u32,
+    /// C
+    c: u32,
+}