Fix the conversion of private names to public names

CHANGELOG.md

@@ -1,3 +1,11 @@
+## 2.3.3
+
+### Module System Migration
+
+* Fix some bugs in the conversion of private names that are references across
+  files to public names, especially when `--remove-prefix` and/or multiple
+  leading dashes/underscores are involved.
+
 ## 2.3.2
 
 * Update to be compatible with the latest version of the Dart Sass AST.

lib/src/migrators/module.dart

@@ -6,6 +6,7 @@
 
 import 'package:args/args.dart';
 import 'package:collection/collection.dart';
+import 'package:charcode/charcode.dart';
 import 'package:path/path.dart' as p;
 import 'package:sass_api/sass_api.dart';
 import 'package:source_span/source_span.dart';
@@ -263,7 +264,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
     var forwardsByUrl = <Uri, Map<String, Set<MemberDeclaration>>>{};
     var hiddenByUrl = <Uri, Set<MemberDeclaration>>{};
     for (var declaration in references.globalDeclarations) {
-      var private = declaration.name.startsWith('-');
+      var private = _isPrivate(declaration.name);
 
       // Whether this member will be exposed by the regular entrypoint.
       var visibleAtEntrypoint = !private &&
@@ -352,19 +353,39 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
     if (declaration.isForwarded) return;
 
     var name = declaration.name;
-    if (name.startsWith('-') &&
-        references.referencedOutsideDeclaringStylesheet(declaration)) {
-      // Remove leading `-` since private members can't be accessed outside
-      // the module they're declared in.
-      name = name.substring(1);
-    }
-    name = _unprefix(name);
+    name = _unprefix(name,
+        // Private members can't be accessed outside the module they're
+        // declared in.
+        forcePublic:
+            references.referencedOutsideDeclaringStylesheet(declaration));
     if (name != declaration.name) {
       renamedMembers[declaration] = name;
       if (_upstreamStylesheets.isEmpty) _needsImportOnly = true;
     }
   }
 
+  /// Returns whether [identifier] is a private member name.
+  ///
+  /// Assumes [identifier] is a valid CSS identifier.
+  bool _isPrivate(String identifier) {
+    return identifier.startsWith('-') || identifier.startsWith('_');
+  }
+
+  /// Converts a private identifier to a public one.
+  String _privateToPublic(String identifier) {
+    if (_isPrivate(identifier)) {
+      for (var i = 0; i < identifier.length; i++) {
+        var char = identifier.codeUnitAt(i);
+        if (char != $dash && char != $underscore) {
+          return identifier.substring(i);
+        }
+      }
+
+      return 'private$identifier';
+    }
+    return identifier;
+  }
+
   /// Returns whether the member named [name] should be forwarded in the
   /// entrypoint.
   ///
@@ -1025,8 +1046,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
         newName = declaration.name.substring(importOnlyPrefix.length);
       }
 
-      if (_shouldForward(declaration.name) &&
-          !declaration.name.startsWith('-')) {
+      if (_shouldForward(declaration.name) && !_isPrivate(declaration.name)) {
         var subprefix = "";
         if (importOnlyPrefix != null) {
           var prefix = _prefixFor(declaration.name);
@@ -1036,7 +1056,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
         }
         if (declaration.name != newName) _needsImportOnly = true;
         shownByPrefix.putIfAbsent(subprefix, () => {}).add(declaration);
-      } else if (!newName.startsWith('-')) {
+      } else if (!_isPrivate(newName)) {
         hidden.add(declaration);
       }
     }
@@ -1076,8 +1096,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
         if (declaration is ImportOnlyMemberDeclaration) {
           name = name.substring(declaration.importOnlyPrefix.length);
         }
-        if (name.startsWith('-')) name = name.substring(1);
-        name = _unprefix(name);
+        name = _unprefix(name, forcePublic: true);
         if (subprefix.isNotEmpty) name = '$subprefix$name';
         if (declaration.member is VariableDeclaration) name = '\$$name';
         allHidden.add(name);
@@ -1205,7 +1224,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
   void _renameReference(FileSpan span, MemberDeclaration declaration) {
     var newName = renamedMembers[declaration];
     if (newName != null) {
-      if (newName.startsWith('-') &&
+      if (_isPrivate(newName) &&
           declaration.name.endsWith(newName.substring(1))) {
         addPatch(patchDelete(span,
             start: 1, end: declaration.name.length - newName.length + 1));
@@ -1225,14 +1244,36 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
 
   /// If [name] starts with any of [prefixesToRemove], returns it with the
   /// longest matching prefix removed.
+  /// If forcePublic is true, any leading dash or underscore will be removed.
   ///
   /// Otherwise, returns [name] unaltered.
-  String _unprefix(String name) {
-    var isPrivate = name.startsWith('-');
-    var unprivateName = isPrivate ? name.substring(1) : name;
-    var prefix = _prefixFor(unprivateName);
-    if (prefix == null) return name;
-    return (isPrivate ? '-' : '') + unprivateName.substring(prefix.length);
+  ///
+  /// If [forcePublic] is true, this will ensure that the name is always a
+  /// public identifier.
+  String _unprefix(String name, {bool forcePublic = false}) {
+    bool isPrivate;
+    String withoutPrefix;
+
+    // Allow users to pass prefixes that either do or do not include leading
+    // dashes/underscores. As usual, the longest prefix wins, so we check for
+    // ones that do include them first.
+    var prefix = _prefixFor(name);
+    if (prefix != null) {
+      isPrivate = false;
+      withoutPrefix = name.substring(prefix.length);
+    } else {
+      isPrivate = _isPrivate(name);
+      var unprivateName = isPrivate ? _privateToPublic(name) : name;
+      prefix = _prefixFor(unprivateName);
+      if (prefix == null)
+        return isPrivate && forcePublic ? unprivateName : name;
+      withoutPrefix = unprivateName.substring(prefix.length);
+    }
+
+    if (_isPrivate(withoutPrefix)) {
+      withoutPrefix = _privateToPublic(withoutPrefix);
+    }
+    return (isPrivate && !forcePublic ? '-' : '') + withoutPrefix;
   }
 
   /// Returns the namespace that built-in module [module] is loaded under.

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass_migrator
-version: 2.3.2
+version: 2.3.3
 description: A tool for running migrations on Sass files
 homepage: https://github.com/sass/migrator
 

test/migrators/module/remove_prefix_flag/pseudoprivate_multi_dash.hrx

@@ -0,0 +1,22 @@
+<==> arguments
+--migrate-deps --remove-prefix=lib-
+
+<==> input/entrypoint.scss
+@import "dependency";
+
+a {
+  background: $--lib-pseudoprivate;
+}
+
+<==> input/_dependency.scss
+$--lib-pseudoprivate: blue;
+
+<==> output/entrypoint.scss
+@use "dependency";
+
+a {
+  background: dependency.$pseudoprivate;
+}
+
+<==> output/_dependency.scss
+$pseudoprivate: blue;

test/migrators/module/remove_prefix_flag/with_dash.hrx

@@ -0,0 +1,25 @@
+<==> arguments
+--migrate-deps --remove-prefix=--app-
+<==> input/entrypoint.scss
+@import "library";
+a {
+  color: $--app-var;
+  background: $__app-var2;
+}
+
+<==> input/_library.scss
+$--app-red: red;
+$--app-var: $--app-red;
+$__app-var2: blue;
+
+<==> output/entrypoint.scss
+@use "library";
+a {
+  color: library.$var;
+  background: library.$var2;
+}
+
+<==> output/_library.scss
+$red: red;
+$var: $red;
+$var2: blue;

test/migrators/module/remove_prefix_flag/with_leading_dash.hrx

@@ -0,0 +1,36 @@
+<==> arguments
+--remove-prefix=--lib-
+
+<==> input/entrypoint.scss
+$--lib-a: 5;
+$--lib_b: $--lib-a + 2;
+
+@function --lib-fn($--lib-local) {
+  @return $--lib-local;
+}
+
+@mixin --lib-mixin {
+  --lib-property: --lib-value;
+}
+
+--lib-selector {
+  property: --lib-fn(0);
+  @include --lib-mixin;
+}
+
+<==> output/entrypoint.scss
+$a: 5;
+$b: $a + 2;
+
+@function fn($--lib-local) {
+  @return $--lib-local;
+}
+
+@mixin mixin {
+  --lib-property: --lib-value;
+}
+
+--lib-selector {
+  property: fn(0);
+  @include mixin;
+}

test/migrators/module/remove_prefix_flag/without_dash.hrx

@@ -0,0 +1,39 @@
+<==> arguments
+--remove-prefix=lib
+
+<==> input/entrypoint.scss
+$lib-a: 5;
+$lib_b: $lib-a + 2;
+
+@function lib-fn($lib-local) {
+  @return $lib-local;
+}
+
+@mixin lib-mixin {
+  lib-property: lib-value;
+}
+
+lib-selector {
+  lib-property: lib-fn(0);
+  @include lib-mixin;
+}
+
+<==> output/entrypoint.scss
+$a: 5;
+$b: $a + 2;
+
+@function fn($lib-local) {
+  @return $lib-local;
+}
+
+@mixin mixin {
+  lib-property: lib-value;
+}
+
+lib-selector {
+  lib-property: fn(0);
+  @include mixin;
+}
+
+<==> output/entrypoint.import.scss
+@forward "entrypoint" as lib-*;

test/migrators/module/scope/pseudoprivate/dash.hrx

@@ -0,0 +1,21 @@
+<==> arguments
+--migrate-deps
+<==> input/entrypoint.scss
+@import "library";
+a {
+  color: $-var;
+}
+
+<==> input/_library.scss
+$-red: red;
+$-var: $-red;
+
+<==> output/entrypoint.scss
+@use "library";
+a {
+  color: library.$var;
+}
+
+<==> output/_library.scss
+$-red: red;
+$var: $-red;

test/migrators/module/scope/pseudoprivate/dashes_only.hrx

@@ -0,0 +1,19 @@
+<==> arguments
+--migrate-deps
+<==> input/entrypoint.scss
+@import "library";
+a {
+  color: $---;
+}
+
+<==> input/_library.scss
+$---: red;
+
+<==> output/entrypoint.scss
+@use "library";
+a {
+  color: library.$private---;
+}
+
+<==> output/_library.scss
+$private---: red;

test/migrators/module/scope/pseudoprivate/double_dash.hrx

@@ -0,0 +1,21 @@
+<==> arguments
+--migrate-deps
+<==> input/entrypoint.scss
+@import "library";
+a {
+  color: $--var;
+}
+
+<==> input/_library.scss
+$--red: red;
+$--var: $--red;
+
+<==> output/entrypoint.scss
+@use "library";
+a {
+  color: library.$var;
+}
+
+<==> output/_library.scss
+$--red: red;
+$var: $--red;