Fix a bug generating superfluous import-only files (#179)

Author: jathak

CHANGELOG.md

@@ -1,3 +1,10 @@
+## 1.3.6
+
+### Module Migrator
+
+* Fix a bug that could result in unnecessary import-only files being generated
+  when running `--forward=import-only` on a file with no dependencies.
+
 ## 1.3.5
 
 ### Module Migrator

lib/src/migrators/module.dart

@@ -299,7 +299,7 @@ class _ModuleMigrationVisitor extends MigrationVisitor {
     // import-only file is necessary.
     if (forwardsByUrl.isEmpty ||
         (forwardsByUrl.length == 1 &&
-            forwardsByUrl[entrypoint]?.keys == {''})) {
+            forwardsByUrl[entrypoint]?.keys?.join() == '')) {
       return null;
     }
 

pubspec.yaml

@@ -1,5 +1,5 @@
 name: sass_migrator
-version: 1.3.5
+version: 1.3.6
 description: A tool for running migrations on Sass files
 author: Jennifer Thakar <[email protected]>
 homepage: https://github.com/sass/migrator

test/migrators/module/forward_flag/import_only/unnecessary.hrx

@@ -0,0 +1,16 @@
+<==> arguments
+--migrate-deps --forward=import-only
+
+<==> README.md
+This text confirms that import-only files are only generated when they're
+necessary.
+
+<==> input/entrypoint.scss
+$variable: green;
+
+a {
+  color: $variable;
+}
+
+<==> log.txt
+Nothing to migrate!