Fix whitespace collapsing breaking -- style SQL comments

The regex r'\s+' collapsed all whitespace including newlines, which broke
-- style SQL comments by putting everything on one line. Changed to r'[ \t]+'
to only collapse horizontal whitespace while preserving newlines.

Bump version to 4.7.1

Author: nhumrich

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "t-sql"
-version = "4.7.0"
+version = "4.7.1"
 description = "Safe SQL. SQL queries for python t-strings (PEP 750)"
 readme = "README.md"
 requires-python = ">=3.14"

tests/test_deep_nesting.py

@@ -311,7 +311,8 @@ def test_case_expression_with_subqueries():
 
     sql, params = tsql.render(query, style=styles.QMARK)
 
-    assert "CASE WHEN (SELECT COUNT(*)" in sql
+    assert "CASE" in sql
+    assert "WHEN (SELECT COUNT(*)" in sql
     assert "> ?" in sql
     assert "THEN 'active'" in sql
     assert params == [10]

tests/test_tsql.py

@@ -35,15 +35,26 @@ def test_merges_literals_using_exsiting_tstring():
     assert result._sql == 'hello there'
 
 
-def test_strips_literal_whitespace():
-    result = tsql.render(t"SELECT             \n * \n FROM               table")
+def test_strips_horizontal_whitespace():
+    # Horizontal whitespace (spaces/tabs) is collapsed, but newlines are preserved
+    result = tsql.render(t"SELECT		    *    FROM               table")
     assert result[0] == 'SELECT * FROM table'
 
 
+def test_preserves_newlines_for_sql_comments():
+    # Newlines must be preserved so -- style SQL comments work correctly
+    query = t"""SELECT * FROM users
+-- Filter by active status
+WHERE active = true"""
+    result = tsql.render(query)
+    assert '-- Filter by active status\n' in result[0]
+    assert 'WHERE active = true' in result[0]
+
+
 def test_doesnt_strip_whitespace_in_values():
     user_input = 'Some string\nWith whitespace.    With Formating    that is   \n  just right'
-    result = tsql.render(t'INSERT \n INTO table (vals) VALUES({user_input})')
-    assert result[0] == f'INSERT INTO table (vals) VALUES(?)'
+    result = tsql.render(t'INSERT INTO table (vals) VALUES({user_input})')
+    assert result[0] == 'INSERT INTO table (vals) VALUES(?)'
     assert result[1] == [user_input]
 
 

tsql/__init__.py

@@ -9,8 +9,9 @@
 
 logger = logging.getLogger(__name__)
 
-# Pre-compile regex for whitespace collapsing to avoid cache lookup overhead
-_WHITESPACE_RE = re.compile(r'\s+')
+# Pre-compile regex for horizontal whitespace collapsing (spaces/tabs only)
+# Preserves newlines so that -- style SQL comments work correctly
+_WHITESPACE_RE = re.compile(r'[ \t]+')
 
 if TYPE_CHECKING:
     from tsql.query_builder import QueryBuilder