Merge "Render NULL for bindparam w/ None value/literal_binds, warn"

1 files changed, 10 insertions, 4 deletions

diff --git a/lib/sqlalchemy/sql/compiler.py b/lib/sqlalchemy/sql/compiler.py
index aabc257eb..353de2c48 100644
--- a/lib/sqlalchemy/sql/compiler.py
+++ b/lib/sqlalchemy/sql/compiler.py
@@ -2055,6 +2055,7 @@ class SQLCompiler(Compiled):
         _in_binary = kw.get("_in_binary", False)
 
         kw["_in_binary"] = True
+        kw["_binary_op"] = binary.operator
         text = (
             binary.left._compiler_dispatch(
                 self, eager_grouping=eager_grouping, **kw
@@ -2306,10 +2307,15 @@ class SQLCompiler(Compiled):
             value = render_literal_value
         else:
             if bindparam.value is None and bindparam.callable is None:
-                raise exc.CompileError(
-                    "Bind parameter '%s' without a "
-                    "renderable value not allowed here." % bindparam.key
-                )
+                op = kw.get("_binary_op", None)
+                if op and op not in (operators.is_, operators.is_not):
+                    util.warn_limited(
+                        "Bound parameter '%s' rendering literal NULL in a SQL "
+                        "expression; comparisons to NULL should not use "
+                        "operators outside of 'is' or 'is not'",
+                        (bindparam.key,),
+                    )
+                return self.process(sqltypes.NULLTYPE, **kw)
             value = bindparam.effective_value
 
         if bindparam.expanding: