Add strict unary migrator (#227)

Author: jathak

CHANGELOG.md

@@ -1,3 +1,10 @@
+## 1.6.0
+
+### Strict Unary Migrator
+
+* Add a new migrator for eliminating ambiguous syntax for the `+` and `-`
+  operators that will soon be deprecated.
+
 ## 1.5.6
 
 * No user-visible changes.

lib/src/migrators/strict_unary.dart

@@ -0,0 +1,47 @@
+// Copyright 2022 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:sass_api/sass_api.dart';
+
+import '../migration_visitor.dart';
+import '../migrator.dart';
+import '../patch.dart';
+
+/// Migrates deprecated `$a -$b` construct to unambiguous `$a - $b`.
+class StrictUnaryMigrator extends Migrator {
+  final name = "strict-unary";
+  final description = r"Migrates deprecated `$a -$b` syntax (and similar) to "
+      r"unambiguous `$a - $b`";
+
+  @override
+  Map<Uri, String> migrateFile(
+      ImportCache importCache, Stylesheet stylesheet, Importer importer) {
+    var visitor = _UnaryMigrationVisitor(importCache, migrateDependencies);
+    var result = visitor.run(stylesheet, importer);
+    missingDependencies.addAll(visitor.missingDependencies);
+    return result;
+  }
+}
+
+class _UnaryMigrationVisitor extends MigrationVisitor {
+  _UnaryMigrationVisitor(ImportCache importCache, bool migrateDependencies)
+      : super(importCache, migrateDependencies);
+
+  @override
+  void visitBinaryOperationExpression(BinaryOperationExpression node) {
+    if (node.operator == BinaryOperator.plus ||
+        node.operator == BinaryOperator.minus) {
+      var betweenOperands = node.span.file
+          .span(node.left.span.end.offset, node.right.span.start.offset)
+          .text;
+      if (betweenOperands.startsWith(RegExp(r'\s')) &&
+          betweenOperands.endsWith(node.operator.operator)) {
+        addPatch(Patch.insert(node.right.span.start, ' '));
+      }
+    }
+    super.visitBinaryOperationExpression(node);
+  }
+}

lib/src/runner.dart

@@ -16,6 +16,7 @@ import 'io.dart';
 import 'migrators/division.dart';
 import 'migrators/module.dart';
 import 'migrators/namespace.dart';
+import 'migrators/strict_unary.dart';
 import 'exception.dart';
 
 /// A command runner that runs a migrator based on provided arguments.
@@ -55,6 +56,7 @@ class MigratorRunner extends CommandRunner<Map<Uri, String>> {
     addCommand(DivisionMigrator());
     addCommand(ModuleMigrator());
     addCommand(NamespaceMigrator());
+    addCommand(StrictUnaryMigrator());
   }
 
   /// Runs a migrator and then writes the migrated files to disk unless

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass_migrator
-version: 1.5.7-dev
+version: 1.6.0
 description: A tool for running migrations on Sass files
 homepage: https://github.com/sass/migrator
 
@@ -10,13 +10,12 @@ dependencies:
   args: ^2.1.0
   charcode: ^1.2.0
   collection: ^1.16.0
-  # Workaround until pulyaevskiy/node-interop#110 is resolved
-  file: '>=6.1.0 <6.1.2'
+  file: ^6.1.4
   glob: ^2.0.1
   js: ^0.6.3
   meta: ^1.3.0
   node_interop: ^2.0.2
-  node_io: ^2.1.0
+  node_io: ^2.2.0
   path: ^1.8.0
   sass_api: ^3.0.0
   source_span: ^1.8.1

test/migrators/namespace_node_test.dart

@@ -12,5 +12,5 @@ import '../utils.dart';
 
 main() {
   runNodeTests = true;
-  testMigrator("division");
+  testMigrator("namespace");
 }

test/migrators/strict_unary/add_whitespace.hrx

@@ -0,0 +1,31 @@
+<==> input/entrypoint.scss
+$x: 1;
+$y: 2;
+
+plus {
+  a: $x +$y;
+  b: ($x) +($y);
+  c: $x +$y +$y;
+}
+
+minus {
+  a: $x -$y;
+  b: ($x) -($y);
+  c: $x -$y -$y;
+}
+
+<==> output/entrypoint.scss
+$x: 1;
+$y: 2;
+
+plus {
+  a: $x + $y;
+  b: ($x) + ($y);
+  c: $x + $y + $y;
+}
+
+minus {
+  a: $x - $y;
+  b: ($x) - ($y);
+  c: $x - $y - $y;
+}

test/migrators/strict_unary/no_change.hrx

@@ -0,0 +1,20 @@
+<==> input/entrypoint.scss
+$x: 1;
+$y: 2;
+
+plus {
+  a: $x+$y;
+  b: $x + $y;
+  c: $x (+$y);
+  d: $x+ $y;
+}
+
+minus {
+  a: ($x)-$y;
+  b: $x - $y;
+  c: $x (-$y);
+  d: ($x)- $y;
+}
+
+<==> log.txt
+Nothing to migrate!

test/migrators/strict_unary_dart_test.dart

@@ -0,0 +1,11 @@
+// Copyright 2022 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import '../utils.dart';
+
+main() {
+  testMigrator("strict_unary");
+}

test/migrators/strict_unary_node_test.dart

@@ -0,0 +1,16 @@
+// Copyright 2022 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+@Tags(["node"])
+
+import 'package:test/test.dart';
+
+import '../utils.dart';
+
+main() {
+  runNodeTests = true;
+  testMigrator("strict_unary");
+}

test/utils.dart

@@ -56,7 +56,7 @@ Future<void> _testHrx(File hrxFile, String migrator) async {
   await files.unpack();
 
   var process = await runMigrator([
-    migrator,
+    migrator.replaceAll('_', '-'),
     '--no-unicode',
     ...files.arguments,
     for (var path in files.input.keys)