Correctly indent multiline comments when retainLines: true (#12260)

packages/babel-generator/src/printer.js

@@ -612,7 +612,7 @@ export default class Printer {
 
       const indentSize = Math.max(
         this._getIndent().length,
-        this._buf.getCurrentColumn(),
+        this.format.retainLines ? 0 : this._buf.getCurrentColumn(),
       );
       val = val.replace(/\n(?!$)/g, `\n${" ".repeat(indentSize)}`);
     }

packages/babel-generator/test/fixtures/comments/multi-comment-with-retainlines-option/input.js

@@ -0,0 +1,15 @@
+var foo = "this is a long string";
+
+/**
+ * this is comment
+ */
+class Bar {}
+
+{
+  const foo = "this is a really long line of text. this is a really long line of text.";
+
+  /**
+   * Example
+   */
+  class A {}
+}

packages/babel-generator/test/fixtures/comments/multi-comment-with-retainlines-option/options.json

@@ -0,0 +1,3 @@
+{
+  "retainLines": true
+}

packages/babel-generator/test/fixtures/comments/multi-comment-with-retainlines-option/output.js

@@ -0,0 +1,15 @@
+var foo = "this is a long string";
+
+/**
+ * this is comment
+ */
+class Bar {}
+
+{
+  const foo = "this is a really long line of text. this is a really long line of text.";
+
+  /**
+   * Example
+   */
+  class A {}
+}