Importer: Allows importer to return error.

* Adds corresponding tests.

Issue URL: #651.
PR URL: #817.

src/custom_importer_bridge.cpp

@@ -16,16 +16,36 @@ SassImportList CustomImporterBridge::post_process_return_value(Handle<Value> val
     for (size_t i = 0; i < array->Length(); ++i) {
       Local<Value> value = array->Get(static_cast<uint32_t>(i));
 
-      if (!value->IsObject())
+      if (!value->IsObject()) {
         continue;
+      }
 
       Local<Object> object = Local<Object>::Cast(value);
-      char* path = create_string(object->Get(NanNew<String>("file")));
-      char* contents = create_string(object->Get(NanNew<String>("contents")));
 
-      imports[i] = sass_make_import_entry(path, (!contents || contents[0] == '\0') ? 0 : strdup(contents), 0);
+      if (value->IsNativeError()) {
+        char* message = create_string(object->Get(NanNew<String>("message")));
+
+        imports[i] = sass_make_import_entry(0, 0, 0);
+
+        sass_import_set_error(imports[i], message, -1, -1);
+      }
+      else {
+        char* path = create_string(object->Get(NanNew<String>("file")));
+        char* contents = create_string(object->Get(NanNew<String>("contents")));
+
+        imports[i] = sass_make_import_entry(path, (!contents || contents[0] == '\0') ? 0 : strdup(contents), 0);
+      }
     }
   }
+  else if (returned_value->IsNativeError()) {
+    imports = sass_make_import_list(1);
+    Local<Object> object = Local<Object>::Cast(returned_value);
+    char* message = create_string(object->Get(NanNew<String>("message")));
+
+    imports[0] = sass_make_import_entry(0, 0, 0);
+
+    sass_import_set_error(imports[0], message, -1, -1);
+  }
   else if (returned_value->IsObject()) {
     imports = sass_make_import_list(1);
     Local<Object> object = Local<Object>::Cast(returned_value);
@@ -46,7 +66,7 @@ std::vector<Handle<Value>> CustomImporterBridge::pre_process_args(std::vector<vo
   std::vector<Handle<Value>> out;
 
   for (void* ptr : in) {
-    out.push_back(NanNew<String>((char const*) ptr));
+    out.push_back(NanNew<String>((char const*)ptr));
   }
 
   return out;

test/api.js

@@ -387,6 +387,30 @@ describe('api', function() {
         done();
       });
     });
+
+    it('should reflect user-defined error when returned as callback', function(done) {
+      sass.render({
+        data: src,
+        importer: function(url, prev, done) {
+          done(new Error('doesn\'t exist!'));
+        }
+      }, function(error) {
+        assert.equal(error.message, 'doesn\'t exist!');
+        done();
+      });
+    });
+
+    it('should reflect user-defined error with return', function(done) {
+      sass.render({
+        data: src,
+        importer: function() {
+          return new Error('doesn\'t exist!');
+        }
+      }, function(error) {
+        assert.equal(error.message, 'doesn\'t exist!');
+        done();
+      });
+    });
   });
 
   describe('.render(functions)', function() {
@@ -1136,6 +1160,20 @@ describe('api', function() {
       assert.equal(sync, true);
       done();
     });
+
+
+    it('should throw user-defined error', function(done) {
+      assert.throws(function() {
+        sass.renderSync({
+          data: src,
+          importer: function() {
+            return new Error('doesn\'t exist!');
+          }
+        });
+      }, /doesn\'t exist!/);
+
+      done();
+    });
   });
 
   describe('.render({stats: {}})', function() {
@@ -1390,14 +1428,10 @@ describe('api', function() {
       assert.throws(function() {
         fs.renameSync(originalBin, renamedBin);
         process.sass.getBinaryPath(true);
-      }, function(err) {
-        fs.renameSync(renamedBin, originalBin);
+      }, /`libsass` bindings not found. Try reinstalling `node-sass`?/);
 
-        if ((err instanceof Error) && /`libsass` bindings not found. Try reinstalling `node-sass`?/.test(err)) {
-          done();
-          return true;
-        }
-      });
+      fs.renameSync(renamedBin, originalBin);
+      done();
     });
   });
 });

test/cli.js

@@ -410,7 +410,7 @@ describe('cli', function() {
       });
     });
 
-    it('should return error on for invalid importer file path', function(done) {
+    it('should return error for invalid importer file path', function(done) {
       var bin = spawn(cli, [
         src, '--output', path.dirname(dest),
         '--importer', fixture('non/existing/path')
@@ -421,6 +421,18 @@ describe('cli', function() {
         done();
       });
     });
+
+    it('should reflect user-defined Error', function(done) {
+      var bin = spawn(cli, [
+        src, '--output', path.dirname(dest),
+        '--importer', fixture('extras/my_custom_importer_error.js')
+      ]);
+
+      bin.stderr.once('data', function(code) {
+        assert.equal(JSON.parse(code).message, 'doesn\'t exist!');
+        done();
+      });
+    });
   });
 
   describe('functions', function() {

test/fixtures/extras/my_custom_importer_error.js

+module.exports = function() {
+  return new Error('doesn\'t exist!');
+};