refactor(es/ast): Remove Hash from ECMA AST nodes

Author: magic-akari

.changeset/remove-ecma-ast-hash.md

@@ -0,0 +1,10 @@
+---
+swc_bundler: major
+swc_core: major
+swc_ecma_ast: major
+swc_ecma_lints: major
+swc_ecma_minifier: major
+swc_ecma_parser: major
+---
+
+refactor(es/ast): Remove `Hash` implementations from ECMA AST nodes

crates/swc_bundler/src/bundler/export.rs

@@ -1,7 +1,7 @@
 use indexmap::IndexMap;
 use rustc_hash::FxBuildHasher;
-use swc_atoms::{atom, Atom};
-use swc_common::{FileName, SyntaxContext};
+use swc_atoms::{atom, Atom, Wtf8Atom};
+use swc_common::{FileName, Span, SyntaxContext};
 use swc_ecma_ast::*;
 use swc_ecma_utils::find_pat_ids;
 use swc_ecma_visit::{noop_visit_mut_type, VisitMut, VisitMutWith};
@@ -42,8 +42,71 @@ where
 
 #[derive(Debug, Default)]
 pub(super) struct RawExports {
-    /// Key is None if it's exported from the module itself.
-    pub items: IndexMap<Option<Str>, Vec<Specifier>, FxBuildHasher>,
+    /// Exports declared by the module itself.
+    pub items: Vec<Specifier>,
+
+    /// Exports forwarded from exactly matching source nodes, in declaration
+    /// order.
+    pub reexports: IndexMap<RawExportSource, Vec<Specifier>, FxBuildHasher>,
+}
+
+impl RawExports {
+    /// Returns the group for an exactly matching source node.
+    ///
+    /// A private key preserves ordered-map performance and semantics without
+    /// requiring [`Str`] to implement `Hash`.
+    fn reexports_for(&mut self, src: Str) -> &mut Vec<Specifier> {
+        self.reexports.entry(src.into()).or_default()
+    }
+}
+
+/// Hashable representation used only by the bundler's export index.
+///
+/// Exhaustive conversions ensure this key stays aligned with [`Str`] if the
+/// AST node gains or loses fields.
+#[derive(Debug, PartialEq, Eq, Hash)]
+pub(super) struct RawExportSource {
+    span: Span,
+    value: Wtf8Atom,
+    raw: Option<Atom>,
+}
+
+impl From<Str> for RawExportSource {
+    fn from(src: Str) -> Self {
+        let Str { span, value, raw } = src;
+
+        Self { span, value, raw }
+    }
+}
+
+impl From<RawExportSource> for Str {
+    fn from(src: RawExportSource) -> Self {
+        let RawExportSource { span, value, raw } = src;
+
+        Self { span, value, raw }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use swc_common::DUMMY_SP;
+
+    use super::*;
+
+    #[test]
+    fn groups_identical_reexport_sources() {
+        let src = Str {
+            span: DUMMY_SP,
+            value: "dependency".into(),
+            raw: None,
+        };
+        let mut exports = RawExports::default();
+
+        let _ = exports.reexports_for(src.clone());
+        let _ = exports.reexports_for(src);
+
+        assert_eq!(exports.reexports.len(), 1);
+    }
 }
 
 #[derive(Debug, Default)]
@@ -151,7 +214,7 @@ where
             //                return ModuleItem::Stmt(Stmt::Empty(EmptyStmt { span: DUMMY_SP }));
             //            }
             ModuleItem::ModuleDecl(ModuleDecl::ExportDecl(decl)) => {
-                let v = self.info.items.entry(None).or_default();
+                let v = &mut self.info.items;
                 v.push({
                     let i = match decl.decl {
                         Decl::Class(ref c) => &c.ident,
@@ -179,25 +242,17 @@ where
             }
 
             ModuleItem::ModuleDecl(ModuleDecl::ExportDefaultDecl(_decl)) => {
-                self.info
-                    .items
-                    .entry(None)
-                    .or_default()
-                    .push(Specifier::Specific {
-                        local: Id::new(atom!("default"), SyntaxContext::empty()),
-                        alias: None,
-                    });
+                self.info.items.push(Specifier::Specific {
+                    local: Id::new(atom!("default"), SyntaxContext::empty()),
+                    alias: None,
+                });
             }
 
             ModuleItem::ModuleDecl(ModuleDecl::ExportDefaultExpr(_expr)) => {
-                self.info
-                    .items
-                    .entry(None)
-                    .or_default()
-                    .push(Specifier::Specific {
-                        local: Id::new(atom!("default"), SyntaxContext::empty()),
-                        alias: None,
-                    });
+                self.info.items.push(Specifier::Specific {
+                    local: Id::new(atom!("default"), SyntaxContext::empty()),
+                    alias: None,
+                });
             }
 
             ModuleItem::ModuleDecl(ModuleDecl::ExportNamed(named)) => {
@@ -207,11 +262,11 @@ where
                 });
                 let mut need_wrapping = false;
 
-                let v = self
-                    .info
-                    .items
-                    .entry(named.src.clone().map(|v| *v))
-                    .or_default();
+                let v = if let Some(src) = named.src.clone() {
+                    self.info.reexports_for(*src)
+                } else {
+                    &mut self.info.items
+                };
                 for s in &mut named.specifiers {
                     match s {
                         ExportSpecifier::Namespace(n) => {
@@ -309,7 +364,7 @@ where
                     .encode(&mut all.with);
                 }
 
-                self.info.items.entry(Some(*all.src.clone())).or_default();
+                let _ = self.info.reexports_for(*all.src.clone());
             }
             _ => {}
         }

crates/swc_bundler/src/bundler/load.rs

@@ -235,46 +235,35 @@ where
             let mut files = Vec::new();
 
             let mut exports = Exports::default();
+            exports.items.extend(raw.items);
 
-            let items = raw
-                .items
+            let reexports = raw
+                .reexports
                 .into_par_iter()
                 .map(|(src, ss)| -> Result<_, Error> {
                     self.run(|| {
-                        let info = match src {
-                            Some(src) => {
-                                let name = self.resolve(base, &src.value.to_string_lossy())?;
-                                let (id, local_mark, export_mark) =
-                                    self.scope.module_id_gen.gen(&name);
-                                Some((id, local_mark, export_mark, name, src))
-                            }
-                            None => None,
-                        };
-
-                        Ok((info, ss))
+                        let src: Str = src.into();
+                        let name = self.resolve(base, &src.value.to_string_lossy())?;
+                        let (id, local_mark, export_mark) = self.scope.module_id_gen.gen(&name);
+
+                        Ok(((id, local_mark, export_mark, name, src), ss))
                     })
                 })
                 .collect::<Vec<_>>();
 
-            for res in items {
-                let (info, specifiers) = res?;
+            for res in reexports {
+                let ((id, local_mark, export_mark, name, src), specifiers) = res?;
 
-                match info {
-                    None => exports.items.extend(specifiers),
-                    Some((id, local_mark, export_mark, name, src)) => {
-                        //
-                        let src = Source {
-                            is_loaded_synchronously: true,
-                            is_unconditional: false,
-                            module_id: id,
-                            local_ctxt: SyntaxContext::empty().apply_mark(local_mark),
-                            export_ctxt: SyntaxContext::empty().apply_mark(export_mark),
-                            src,
-                        };
-                        exports.reexports.push((src.clone(), specifiers));
-                        files.push((src, name));
-                    }
-                }
+                let src = Source {
+                    is_loaded_synchronously: true,
+                    is_unconditional: false,
+                    module_id: id,
+                    local_ctxt: SyntaxContext::empty().apply_mark(local_mark),
+                    export_ctxt: SyntaxContext::empty().apply_mark(export_mark),
+                    src,
+                };
+                exports.reexports.push((src.clone(), specifiers));
+                files.push((src, name));
             }
 
             Ok((exports, files))
@@ -413,7 +402,7 @@ pub(crate) enum Specifier {
     },
 }
 
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub(crate) struct Source {
     pub is_loaded_synchronously: bool,
     pub is_unconditional: bool,

crates/swc_bundler/src/util.rs

@@ -2,6 +2,7 @@
 
 use std::hash::Hash;
 
+#[cfg(feature = "concurrent")]
 use rustc_hash::FxBuildHasher;
 #[cfg(not(feature = "concurrent"))]
 use rustc_hash::FxHashMap;

crates/swc_ecma_ast/src/class.rs

@@ -15,7 +15,7 @@ use crate::{
 };
 
 #[ast_node]
-#[derive(Eq, Hash, EqIgnoreSpan, Default)]
+#[derive(Eq, EqIgnoreSpan, Default)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
 pub struct Class {
@@ -67,7 +67,7 @@ impl Take for Class {
 }
 
 #[ast_node]
-#[derive(Eq, Hash, Is, EqIgnoreSpan)]
+#[derive(Eq, Is, EqIgnoreSpan)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
 pub enum ClassMember {
@@ -104,7 +104,7 @@ impl Take for ClassMember {
 }
 
 #[ast_node("ClassProperty")]
-#[derive(Eq, Hash, EqIgnoreSpan, Default)]
+#[derive(Eq, EqIgnoreSpan, Default)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
 pub struct ClassProp {
@@ -162,7 +162,7 @@ pub struct ClassProp {
 }
 
 #[ast_node("PrivateProperty")]
-#[derive(Eq, Hash, EqIgnoreSpan, Default)]
+#[derive(Eq, EqIgnoreSpan, Default)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
 pub struct PrivateProp {
@@ -216,7 +216,7 @@ pub struct PrivateProp {
 }
 
 #[ast_node("ClassMethod")]
-#[derive(Eq, Hash, EqIgnoreSpan, Default)]
+#[derive(Eq, EqIgnoreSpan, Default)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
 pub struct ClassMethod {
@@ -244,7 +244,7 @@ pub struct ClassMethod {
 }
 
 #[ast_node("PrivateMethod")]
-#[derive(Eq, Hash, EqIgnoreSpan, Default)]
+#[derive(Eq, EqIgnoreSpan, Default)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
 pub struct PrivateMethod {
@@ -272,7 +272,7 @@ pub struct PrivateMethod {
 }
 
 #[ast_node("Constructor")]
-#[derive(Eq, Hash, EqIgnoreSpan, Default)]
+#[derive(Eq, EqIgnoreSpan, Default)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
 pub struct Constructor {
@@ -303,7 +303,7 @@ pub struct Constructor {
 }
 
 #[ast_node("Decorator")]
-#[derive(Eq, Hash, EqIgnoreSpan, Default)]
+#[derive(Eq, EqIgnoreSpan, Default)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
 pub struct Decorator {
@@ -313,7 +313,7 @@ pub struct Decorator {
     pub expr: Box<Expr>,
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, EqIgnoreSpan, Default)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, EqIgnoreSpan, Default)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "serde-impl", derive(serde::Serialize, serde::Deserialize))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
@@ -333,7 +333,7 @@ pub enum MethodKind {
 }
 
 #[ast_node("StaticBlock")]
-#[derive(Eq, Hash, EqIgnoreSpan, Default)]
+#[derive(Eq, EqIgnoreSpan, Default)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
 pub struct StaticBlock {
@@ -352,7 +352,7 @@ impl Take for StaticBlock {
 
 /// Either a private name or a public name.
 #[ast_node]
-#[derive(Is, Eq, Hash, EqIgnoreSpan)]
+#[derive(Is, Eq, EqIgnoreSpan)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
 pub enum Key {
@@ -386,7 +386,7 @@ impl Default for Key {
 }
 
 #[ast_node("AutoAccessor")]
-#[derive(Eq, Hash, EqIgnoreSpan, Default)]
+#[derive(Eq, EqIgnoreSpan, Default)]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[cfg_attr(feature = "shrink-to-fit", derive(shrink_to_fit::ShrinkToFit))]
 pub struct AutoAccessor {