fix: don't add a cast to text literals

Normally cast is not added to unknown literals, and the text oid is not
usually used. However, when it is, it causes problems. Often Postgres
wants just a literal, not a cast type; for instance, this is not valid:

    NOTIFY foo: 'bar'::text;

diff --git a/psycopg/psycopg/_transform.py b/psycopg/psycopg/_transform.py
index 91577f92dd3d49321b4bc6e785b15dd62daa3a9d..200f31c45d905712b770875da41068a7be2987f3 100644 (file)
--- a/psycopg/psycopg/_transform.py
+++ b/psycopg/psycopg/_transform.py
@@ -14,7 +14,7 @@ from . import errors as e
 from .abc import Buffer, LoadFunc, AdaptContext, PyFormat, DumperKey
 from .rows import Row, RowMaker
 from ._compat import TypeAlias
-from .postgres import INVALID_OID
+from .postgres import INVALID_OID, TEXT_OID
 from ._encodings import pgconn_encoding
 
 if TYPE_CHECKING:
@@ -189,11 +189,11 @@ class Transformer(AdaptContext):
     def as_literal(self, obj: Any) -> Buffer:
         dumper = self.get_dumper(obj, PyFormat.TEXT)
         rv = dumper.quote(obj)
-        # If the result is quoted, and the oid not unknown,
+        # If the result is quoted, and the oid not unknown or text,
         # add an explicit type cast.
         # Check the last char because the first one might be 'E'.
         oid = dumper.oid
-        if oid and rv and rv[-1] == b"'"[0]:
+        if oid and rv and rv[-1] == b"'"[0] and oid != TEXT_OID:
             try:
                 type_sql = self._oid_types[oid]
             except KeyError:

diff --git a/psycopg_c/psycopg_c/_psycopg/transform.pyx b/psycopg_c/psycopg_c/_psycopg/transform.pyx
index e290c3adbf67fd291bcbd853fddcbf175e9eb3d5..8f2b5f3ee202e570dacacab45395d440abe041e6 100644 (file)
--- a/psycopg_c/psycopg_c/_psycopg/transform.pyx
+++ b/psycopg_c/psycopg_c/_psycopg/transform.pyx
@@ -215,10 +215,10 @@ cdef class Transformer:
 
         rv = dumper.quote(obj)
         oid = dumper.oid
-        # If the result is quoted and the oid not unknown,
+        # If the result is quoted and the oid not unknown or text,
         # add an explicit type cast.
         # Check the last char because the first one might be 'E'.
-        if oid and rv and rv[-1] == 39:
+        if oid and oid != oids.TEXT_OID and rv and rv[-1] == 39:
             if self._oid_types is None:
                 self._oid_types = {}
             type_ptr = PyDict_GetItem(<object>self._oid_types, oid)

diff --git a/tests/test_adapt.py b/tests/test_adapt.py
index e43038c9b67e24415fd1f71e42a04bafd18ad1e4..7437a71ab47e720a4c12cb60a12362851641ca20 100644 (file)
--- a/tests/test_adapt.py
+++ b/tests/test_adapt.py
@@ -142,7 +142,7 @@ def test_dumper_protocol(conn):
     assert cur.fetchone()[0] == "hellohello"
     cur = conn.execute("select %s", [["hi", "ha"]])
     assert cur.fetchone()[0] == ["hihi", "haha"]
-    assert sql.Literal("hello").as_string(conn) == "'qelloqello'::text"
+    assert sql.Literal("hello").as_string(conn) == "'qelloqello'"
 
 
 def test_loader_protocol(conn):

diff --git a/tests/test_sql.py b/tests/test_sql.py
index 304bcc779eb1886f77ed869670a9f70ddffa1d15..43a58aa27e83c2e581be10c3674ebc9df43cf913 100644 (file)
--- a/tests/test_sql.py
+++ b/tests/test_sql.py
@@ -356,6 +356,10 @@ class TestLiteral:
             == "'{\"2000-01-01 00:00:00\"}'::timestamp[]"
         )
 
+    def test_text_literal(self, conn):
+        conn.adapters.register_dumper(str, StrDumper)
+        assert sql.Literal("foo").as_string(conn) == "'foo'"
+
     @pytest.mark.parametrize("name", ["a-b", f"{eur}", "order", "foo bar"])
     def test_invalid_name(self, conn, name):
         conn.execute(