tweak logic for detecting incomplete formatter blocks (PY-3572)

python/src/com/jetbrains/python/formatter/PyBlock.java

@@ -670,6 +670,15 @@ public class PyBlock implements ASTBlock {
   }
 
   public boolean isIncomplete() {
+    // if there's something following us, we're not incomplete
+    PsiElement element = _node.getPsi().getNextSibling();
+    while (element instanceof PsiWhiteSpace) {
+      element = element.getNextSibling();
+    }
+    if (element != null) {
+      return false;
+    }
+
     ASTNode lastChild = getLastNonSpaceChild(_node, false);
     if (lastChild != null && lastChild.getElementType() == PyElementTypes.STATEMENT_LIST) {
       // only multiline statement lists are considered incomplete

python/testSrc/com/jetbrains/python/PyIndentTest.java

@@ -249,6 +249,22 @@ public class PyIndentTest extends PyLightFixtureTestCase {
            "    <caret>\n");
   }
 
+  public void testIndentAfterModuleLevelStatement() {  // PY-3572
+    doTest("def a(var):\n" +
+           "    if var == 'default':\n" +
+           "        pass\n" +
+           "\n" +
+           "b = 1<caret>\n" +
+           "",
+           "def a(var):\n" +
+           "    if var == 'default':\n" +
+           "        pass\n" +
+           "\n" +
+           "b = 1\n" +
+           "<caret>\n" +
+           "");
+  }
+
   /*
   TODO: formatter core problem?
   public void testAlignListBeforeEquals() throws Exception {