Preserve whitespace after subgroups.

2 files changed, 11 insertions, 4 deletions

diff --git a/sqlparse/filters.py b/sqlparse/filters.py
index 6bb3415..3d2355a 100644
--- a/sqlparse/filters.py
+++ b/sqlparse/filters.py
@@ -218,10 +218,11 @@ class StripWhitespaceFilter(Filter):
             tlist.tokens.pop(-2)
         self._stripws_default(tlist)
 
-    def process(self, stack, stmt):
-        [self.process(stack, sgroup) for sgroup in stmt.get_sublists()]
+    def process(self, stack, stmt, depth=0):
+        [self.process(stack, sgroup, depth+1)
+         for sgroup in stmt.get_sublists()]
         self._stripws(stmt)
-        if stmt.tokens[-1].is_whitespace():
+        if depth == 0 and stmt.tokens[-1].is_whitespace():
             stmt.tokens.pop(-1)
 
 
@@ -610,4 +611,4 @@ class Limit(Filter):
             if index and token_type in Keyword and value == 'LIMIT':
                 return stream[4 - index][1]
 
-        return -1
\ No newline at end of file
+        return -1
diff --git a/tests/test_format.py b/tests/test_format.py
index 7a2c655..c9c6f46 100644
--- a/tests/test_format.py
+++ b/tests/test_format.py
@@ -68,6 +68,12 @@ class TestFormat(TestCaseBase):
         self.assertRaises(sqlparse.SQLParseError, sqlparse.format, s,
                           strip_whitespace=None)
 
+    def test_preserve_ws(self):
+        # preserve at least one whitespace after subgroups
+        f = lambda sql: sqlparse.format(sql, strip_whitespace=True)
+        s = 'select\n* /* foo */  from bar '
+        self.ndiffAssertEqual(f(s), 'select * /* foo */ from bar')
+
     def test_outputformat(self):
         sql = 'select * from foo;'
         self.assertRaises(sqlparse.SQLParseError, sqlparse.format, sql,