Turn off the is_literal flag when proxying literal_column() to Label

Fixed a series of quoting issues which all stemmed from the concept of the
:func:`.literal_column` construct, which when being "proxied" through a
subquery to be referred towards by a label that matches its text, the label
would not have quoting rules applied to it, even if the string in the
:class:`.Label` were set up as a :class:`.quoted_name` construct.  Not
applying quoting to the text of the :class:`.Label` is a bug because this
text is strictly a SQL identifier name and not a SQL expression, and the
string should not have quotes embedded into it already unlike the
:func:`.literal_column` which it may be applied towards.   The existing
behavior of a non-labeled :func:`.literal_column` being propagated as is on
the outside of a subquery is maintained in order to help with manual
quoting schemes, although it's not clear if valid SQL can be generated for
such a construct in any case.

Fixes: #4730
Change-Id: I300941f27872fc4298c74a1d1ed65aef1a5cdd82

1 files changed, 58 insertions, 0 deletions

diff --git a/test/dialect/oracle/test_compiler.py b/test/dialect/oracle/test_compiler.py
index 931079240..f11daebb4 100644
--- a/test/dialect/oracle/test_compiler.py
+++ b/test/dialect/oracle/test_compiler.py
@@ -9,6 +9,7 @@ from sqlalchemy import ForeignKey
 from sqlalchemy import func
 from sqlalchemy import Index
 from sqlalchemy import Integer
+from sqlalchemy import literal_column
 from sqlalchemy import MetaData
 from sqlalchemy import or_
 from sqlalchemy import outerjoin
@@ -25,6 +26,7 @@ from sqlalchemy.dialects.oracle import base as oracle
 from sqlalchemy.dialects.oracle import cx_oracle
 from sqlalchemy.engine import default
 from sqlalchemy.sql import column
+from sqlalchemy.sql import quoted_name
 from sqlalchemy.sql import table
 from sqlalchemy.testing import assert_raises_message
 from sqlalchemy.testing import AssertsCompiledSQL
@@ -260,6 +262,62 @@ class CompileTest(fixtures.TestBase, AssertsCompiledSQL):
             "UPDATE",
         )
 
+    def test_limit_special_quoting(self):
+        """Oracle-specific test for #4730.
+
+        Even though this issue is generic, test the originally reported Oracle
+        use case.
+
+        """
+
+        col = literal_column("SUM(ABC)").label("SUM(ABC)")
+        tbl = table("my_table")
+        query = select([col]).select_from(tbl).order_by(col).limit(100)
+
+        self.assert_compile(
+            query,
+            'SELECT anon_1."SUM(ABC)" FROM '
+            '(SELECT SUM(ABC) AS "SUM(ABC)" '
+            "FROM my_table ORDER BY SUM(ABC)) anon_1 "
+            "WHERE ROWNUM <= :param_1",
+        )
+
+        col = literal_column("SUM(ABC)").label(quoted_name("SUM(ABC)", True))
+        tbl = table("my_table")
+        query = select([col]).select_from(tbl).order_by(col).limit(100)
+
+        self.assert_compile(
+            query,
+            'SELECT anon_1."SUM(ABC)" FROM '
+            '(SELECT SUM(ABC) AS "SUM(ABC)" '
+            "FROM my_table ORDER BY SUM(ABC)) anon_1 "
+            "WHERE ROWNUM <= :param_1",
+        )
+
+        col = literal_column("SUM(ABC)").label("SUM(ABC)_")
+        tbl = table("my_table")
+        query = select([col]).select_from(tbl).order_by(col).limit(100)
+
+        self.assert_compile(
+            query,
+            'SELECT anon_1."SUM(ABC)_" FROM '
+            '(SELECT SUM(ABC) AS "SUM(ABC)_" '
+            "FROM my_table ORDER BY SUM(ABC)) anon_1 "
+            "WHERE ROWNUM <= :param_1",
+        )
+
+        col = literal_column("SUM(ABC)").label(quoted_name("SUM(ABC)_", True))
+        tbl = table("my_table")
+        query = select([col]).select_from(tbl).order_by(col).limit(100)
+
+        self.assert_compile(
+            query,
+            'SELECT anon_1."SUM(ABC)_" FROM '
+            '(SELECT SUM(ABC) AS "SUM(ABC)_" '
+            "FROM my_table ORDER BY SUM(ABC)) anon_1 "
+            "WHERE ROWNUM <= :param_1",
+        )
+
     def test_for_update(self):
         table1 = table(
             "mytable", column("myid"), column("name"), column("description")