Print call-site for @errors in mixins and functions (#878)

For any @errors encountered in mixins or functions, use the call-site
(instead of the @error rule) as the span printed in the error message.

Closes #474
See sass/sass-spec#1494

Author: Awjin

CHANGELOG.md

@@ -1,3 +1,9 @@
+## 1.23.5
+
+* When `@error` is used in a function or mixin, print the call site rather than
+  the location of the `@error` itself to better match the behavior of calling a
+  built-in function that throws an error.
+
 ## 1.23.4
 
 ### Command-Line Interface

lib/src/visitor/async_evaluate.dart

@@ -1469,7 +1469,7 @@ class _EvaluateVisitor
         await _environment.withContent(contentCallable, () async {
           await _environment.asMixin(() async {
             for (var statement in mixin.declaration.children) {
-              await statement.accept(this);
+              await _addErrorSpan(node, () => statement.accept(this));
             }
           });
           return null;
@@ -1983,7 +1983,8 @@ class _EvaluateVisitor
 
     var oldInFunction = _inFunction;
     _inFunction = true;
-    var result = await _runFunctionCallable(node.arguments, function, node);
+    var result = await _addErrorSpan(
+        node, () => _runFunctionCallable(node.arguments, function, node));
     _inFunction = oldInFunction;
     return result;
   }
@@ -2853,6 +2854,19 @@ class _EvaluateVisitor
       throw _exception(error.message, nodeWithSpan.span);
     }
   }
+
+  /// Runs [callback], and converts any [SassRuntimeException]s containing an
+  /// @error to throw a more relevant [SassRuntimeException] with [nodeWithSpan]'s
+  /// source span.
+  Future<T> _addErrorSpan<T>(AstNode nodeWithSpan, Future<T> callback()) async {
+    try {
+      return await callback();
+    } on SassRuntimeException catch (error) {
+      if (!error.span.text.startsWith("@error")) rethrow;
+      throw SassRuntimeException(
+          error.message, nodeWithSpan.span, _stackTrace());
+    }
+  }
 }
 
 /// A helper class for [_EvaluateVisitor] that adds `@import`ed CSS nodes to the

lib/src/visitor/evaluate.dart

@@ -5,7 +5,7 @@
 // DO NOT EDIT. This file was generated from async_evaluate.dart.
 // See tool/grind/synchronize.dart for details.
 //
-// Checksum: 7bcd07f449d67c0f625de8e505a9c74cfed0b616
+// Checksum: 9617d2d08b71858db9228b0858f2f27f87a35bf7
 //
 // ignore_for_file: unused_import
 
@@ -1468,7 +1468,7 @@ class _EvaluateVisitor
         _environment.withContent(contentCallable, () {
           _environment.asMixin(() {
             for (var statement in mixin.declaration.children) {
-              statement.accept(this);
+              _addErrorSpan(node, () => statement.accept(this));
             }
           });
           return null;
@@ -1972,7 +1972,8 @@ class _EvaluateVisitor
 
     var oldInFunction = _inFunction;
     _inFunction = true;
-    var result = _runFunctionCallable(node.arguments, function, node);
+    var result = _addErrorSpan(
+        node, () => _runFunctionCallable(node.arguments, function, node));
     _inFunction = oldInFunction;
     return result;
   }
@@ -2818,6 +2819,19 @@ class _EvaluateVisitor
       throw _exception(error.message, nodeWithSpan.span);
     }
   }
+
+  /// Runs [callback], and converts any [SassRuntimeException]s containing an
+  /// @error to throw a more relevant [SassRuntimeException] with [nodeWithSpan]'s
+  /// source span.
+  T _addErrorSpan<T>(AstNode nodeWithSpan, T callback()) {
+    try {
+      return callback();
+    } on SassRuntimeException catch (error) {
+      if (!error.span.text.startsWith("@error")) rethrow;
+      throw SassRuntimeException(
+          error.message, nodeWithSpan.span, _stackTrace());
+    }
+  }
 }
 
 /// A helper class for [_EvaluateVisitor] that adds `@import`ed CSS nodes to the

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass
-version: 1.23.4
+version: 1.23.5-dev
 description: A Sass implementation in Dart.
 author: Sass Team
 homepage: https://github.com/sass/dart-sass

test/cli/shared/errors.dart

@@ -72,6 +72,56 @@ void sharedTests(Future<TestProcess> runSass(Iterable<String> arguments)) {
     await sass.shouldExit(65);
   });
 
+  test("from an error encountered within a function", () async {
+    await d.file("test.scss", """
+@function a() {
+  @error "Within A.";
+}
+
+.b {
+  c: a();
+}
+""").create();
+
+    var sass = await runSass(["--no-unicode", "test.scss"]);
+    expect(
+        sass.stderr,
+        emitsInOrder([
+          "Error: \"Within A.\"",
+          "  ,",
+          "6 |   c: a();",
+          "  |      ^^^",
+          "  '",
+          "  test.scss 6:6  root stylesheet",
+        ]));
+    await sass.shouldExit(65);
+  });
+
+  test("from an error encountered within a mixin", () async {
+    await d.file("test.scss", """
+@mixin a() {
+  @error "Within A.";
+}
+
+.b {
+  @include a();
+}
+""").create();
+
+    var sass = await runSass(["--no-unicode", "test.scss"]);
+    expect(
+        sass.stderr,
+        emitsInOrder([
+          "Error: \"Within A.\"",
+          "  ,",
+          "6 |   @include a();",
+          "  |   ^^^^^^^^^^^^",
+          "  '",
+          "  test.scss 6:3  root stylesheet",
+        ]));
+    await sass.shouldExit(65);
+  });
+
   test("with colors with --color", () async {
     await d.file("test.scss", "a {b: }").create();