Fix grouping of comments (fixes #772).

The grouping of comments was a bit too greedy by also
consuming whitespaces at the end.

CHANGELOG

@@ -1,7 +1,13 @@
 Development Version
 -------------------
 
-Nothing yet.
+Bug Fixes
+
+* The strip comments filter was a bit greedy and removed too much
+  whitespace (issue772).
+  Note: In some cases you might want to add `strip_whitespace=True` where you
+  previously used just `strip_comments=True`. `strip_comments` did some of the
+  work that `strip_whitespace` should do.
 
 
 Release 0.5.0 (Apr 13, 2024)

sqlparse/engine/grouping.py

@@ -314,7 +314,7 @@ def group_comments(tlist):
     tidx, token = tlist.token_next_by(t=T.Comment)
     while token:
         eidx, end = tlist.token_not_matching(
-            lambda tk: imt(tk, t=T.Comment) or tk.is_whitespace, idx=tidx)
+            lambda tk: imt(tk, t=T.Comment) or tk.is_newline, idx=tidx)
         if end is not None:
             eidx, end = tlist.token_prev(eidx, skip_ws=False)
             tlist.group_tokens(sql.Comment, tidx, eidx)

sqlparse/sql.py

@@ -46,7 +46,7 @@ class Token:
     """
 
     __slots__ = ('value', 'ttype', 'parent', 'normalized', 'is_keyword',
-                 'is_group', 'is_whitespace')
+                 'is_group', 'is_whitespace', 'is_newline')
 
     def __init__(self, ttype, value):
         value = str(value)
@@ -56,6 +56,7 @@ def __init__(self, ttype, value):
         self.is_group = False
         self.is_keyword = ttype in T.Keyword
         self.is_whitespace = self.ttype in T.Whitespace
+        self.is_newline = self.ttype in T.Newline
         self.normalized = value.upper() if self.is_keyword else value
 
     def __str__(self):

tests/test_format.py

@@ -73,15 +73,15 @@ def test_strip_comments_multi(self):
         assert res == 'select'
         sql = '/* sql starts here */ select'
         res = sqlparse.format(sql, strip_comments=True)
-        assert res == 'select'
+        assert res == ' select'  # note whitespace is preserved, see issue 772
         sql = '/*\n * sql starts here\n */\nselect'
         res = sqlparse.format(sql, strip_comments=True)
         assert res == 'select'
         sql = 'select (/* sql starts here */ select 2)'
-        res = sqlparse.format(sql, strip_comments=True)
+        res = sqlparse.format(sql, strip_comments=True, strip_whitespace=True)
         assert res == 'select (select 2)'
         sql = 'select (/* sql /* starts here */ select 2)'
-        res = sqlparse.format(sql, strip_comments=True)
+        res = sqlparse.format(sql, strip_comments=True, strip_whitespace=True)
         assert res == 'select (select 2)'
 
     def test_strip_comments_preserves_linebreak(self):
@@ -100,6 +100,11 @@ def test_strip_comments_preserves_linebreak(self):
         sql = 'select * -- a comment\n\nfrom foo'
         res = sqlparse.format(sql, strip_comments=True)
         assert res == 'select *\n\nfrom foo'
+
+    def test_strip_comments_preserves_whitespace(self):
+        sql = 'SELECT 1/*bar*/ AS foo'  # see issue772
+        res = sqlparse.format(sql, strip_comments=True)
+        assert res == 'SELECT 1 AS foo'
 
     def test_strip_ws(self):
         f = lambda sql: sqlparse.format(sql, strip_whitespace=True)

tests/test_grouping.py

@@ -17,13 +17,6 @@ def test_grouping_parenthesis():
     assert len(parsed.tokens[2].tokens[3].tokens) == 3
 
 
-def test_grouping_comments():
-    s = '/*\n * foo\n */   \n  bar'
-    parsed = sqlparse.parse(s)[0]
-    assert str(parsed) == s
-    assert len(parsed.tokens) == 2
-
-
 @pytest.mark.parametrize('s', ['foo := 1;', 'foo := 1'])
 def test_grouping_assignment(s):
     parsed = sqlparse.parse(s)[0]