Don't try to resolve relative Node importer URLs for source maps (#923)

* Don't try to resolve relative Node importer URLs for source maps

Closes #922

* Reformat

Author: nex3

CHANGELOG.md

@@ -1,10 +1,21 @@
+## 1.24.4
+
+### JavaScript API
+
+* Fix a bug where source map generation would crash with an absolute source map
+  path and a custom importer that returns string file contents.
+
 ## 1.24.3
 
+### Command Line Interface
+
 * Fix a bug where `sass --version` would crash for certain executable
   distributions.
 
 ## 1.24.2
 
+### JavaScript API
+
 * Fix a bug introduced in the previous release that prevented custom importers
   in Node.js from loading import-only files.
 

lib/src/node.dart

@@ -351,6 +351,12 @@ RenderResult _newRenderResult(
     for (var i = 0; i < result.sourceMap.urls.length; i++) {
       var source = result.sourceMap.urls[i];
       if (source == "stdin") continue;
+
+      // URLs handled by Node importers that directly return file contents are
+      // preserved in their original (usually relative) form. They may or may
+      // not be intended as `file:` URLs, but there's nothing we can do about it
+      // either way so we keep them as-is.
+      if (p.url.isRelative(source) || p.url.isRootRelative(source)) continue;
       result.sourceMap.urls[i] = p.url.relative(source, from: sourceMapDirUrl);
     }
 

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass
-version: 1.24.3
+version: 1.24.4
 description: A Sass implementation in Dart.
 author: Sass Team
 homepage: https://github.com/sass/dart-sass

test/node_api/source_map_test.dart

@@ -195,6 +195,21 @@ void main() {
       var map = _jsonUtf8.decode(result.map) as Map<String, Object>;
       expect(map, containsPair("file", "stdin.css"));
     });
+
+    // Regression test for sass/dart-sass#922
+    test("contains a URL handled by an importer when sourceMap is absolute",
+        () {
+      var map = _renderSourceMap(RenderOptions(
+          data: '''
+        @import "other";
+        a {b: c}
+      ''',
+          importer: allowInterop(
+              (void _, void __) => NodeImporterResult(contents: 'x {y: z}')),
+          sourceMap: p.absolute("out.css.map"),
+          outFile: 'out.css'));
+      expect(map, containsPair("sources", ["other", "stdin"]));
+    });
   });
 
   test("with omitSourceMapUrl, doesn't include a source map comment", () {