Improve custom type comparison error messages and validation (#438)

tomas-villagesql · mjamaloney · commit 1a9a52ff38ae · 2026-02-18T14:23:23.000-05:00
GitOrigin-RevId: 1c78d4980e7d5ff80b34c58bf0dcd7cb0e0681a7
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/r/cross_join_mixed_comparison.result b/mysql-test/suite/villagesql/implicit_cast/disallowed/r/cross_join_mixed_comparison.result
@@ -3,6 +3,6 @@ CREATE TABLE t_string (id INT, val VARCHAR(100));
 INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
 INSERT INTO t_string VALUES (1, 'hello');
 SELECT * FROM t_complex c CROSS JOIN t_string s WHERE c.val < s.val;
-ERROR HY000: Cannot compare values of custom and non-custom types in <
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in <
 DROP TABLE t_complex;
 DROP TABLE t_string;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/r/cross_type_comparison_complex_numeric.result b/mysql-test/suite/villagesql/implicit_cast/disallowed/r/cross_type_comparison_complex_numeric.result
@@ -3,6 +3,17 @@ CREATE TABLE t_numeric (id INT, val DECIMAL(10,2));
 INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
 INSERT INTO t_numeric VALUES (1, 10.50);
 SELECT * FROM t_complex c, t_numeric n WHERE c.val = n.val;
-ERROR HY000: Cannot compare values of custom and non-custom types in =
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in =
 DROP TABLE t_complex;
 DROP TABLE t_numeric;
+CREATE TABLE t_mixed (id INT, complex_col COMPLEX, decimal_col DECIMAL(10,2), int_col INT);
+INSERT INTO t_mixed VALUES (1, '(1.0,2.0)', 1.5, 5);
+SELECT * FROM t_mixed WHERE complex_col = decimal_col;
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in =
+SELECT * FROM t_mixed WHERE complex_col = int_col;
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in =
+SELECT * FROM t_mixed WHERE complex_col = 5;
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in =
+SELECT * FROM t_mixed WHERE complex_col = 1.5;
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in =
+DROP TABLE t_mixed;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/r/cross_type_comparison_complex_string.result b/mysql-test/suite/villagesql/implicit_cast/disallowed/r/cross_type_comparison_complex_string.result
@@ -3,6 +3,6 @@ CREATE TABLE t_string (id INT, val VARCHAR(100));
 INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
 INSERT INTO t_string VALUES (1, 'hello');
 SELECT * FROM t_complex c, t_string s WHERE c.val = s.val;
-ERROR HY000: Cannot compare values of custom and non-custom types in =
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in =
 DROP TABLE t_complex;
 DROP TABLE t_string;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/r/exists_subquery_mixed_comparison.result b/mysql-test/suite/villagesql/implicit_cast/disallowed/r/exists_subquery_mixed_comparison.result
@@ -3,6 +3,6 @@ CREATE TABLE t_string (id INT, val VARCHAR(100));
 INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
 INSERT INTO t_string VALUES (1, 'hello');
 SELECT * FROM t_complex c WHERE EXISTS (SELECT 1 FROM t_string s WHERE c.val = s.val);
-ERROR HY000: Cannot compare values of custom and non-custom types in =
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in =
 DROP TABLE t_complex;
 DROP TABLE t_string;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/r/group_by_complex_expression.result b/mysql-test/suite/villagesql/implicit_cast/disallowed/r/group_by_complex_expression.result
@@ -1,5 +1,5 @@
 CREATE TABLE t_complex (id INT, val COMPLEX);
 INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
 SELECT COUNT(*) FROM t_complex GROUP BY val || 'test';
-ERROR HY000: Cannot compare values of custom and non-custom types in <>
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in <>
 DROP TABLE t_complex;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/r/join_mixed_types.result b/mysql-test/suite/villagesql/implicit_cast/disallowed/r/join_mixed_types.result
@@ -0,0 +1,8 @@
+CREATE TABLE t_complex (id INT, val COMPLEX);
+CREATE TABLE t_string (id INT, val VARCHAR(100));
+INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
+INSERT INTO t_string VALUES (1, 'hello');
+SELECT * FROM t_complex c JOIN t_string s ON c.val = s.val;
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in =
+DROP TABLE t_complex;
+DROP TABLE t_string;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/r/left_join_mixed_types.result b/mysql-test/suite/villagesql/implicit_cast/disallowed/r/left_join_mixed_types.result
@@ -0,0 +1,8 @@
+CREATE TABLE t_complex (id INT, val COMPLEX);
+CREATE TABLE t_numeric (id INT, val DECIMAL(10,2));
+INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
+INSERT INTO t_numeric VALUES (1, 10.50);
+SELECT * FROM t_complex c LEFT JOIN t_numeric n ON c.val = n.val;
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in =
+DROP TABLE t_complex;
+DROP TABLE t_numeric;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/r/multi_table_delete_mixed_comparison.result b/mysql-test/suite/villagesql/implicit_cast/disallowed/r/multi_table_delete_mixed_comparison.result
@@ -0,0 +1,8 @@
+CREATE TABLE t_complex (id INT, val COMPLEX);
+CREATE TABLE t_string (id INT, val VARCHAR(100));
+INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
+INSERT INTO t_string VALUES (1, 'hello');
+DELETE c FROM t_complex c, t_string s WHERE c.val = s.val;
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in =
+DROP TABLE t_complex;
+DROP TABLE t_string;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/r/subquery_comparison_numeric.result b/mysql-test/suite/villagesql/implicit_cast/disallowed/r/subquery_comparison_numeric.result
@@ -3,6 +3,6 @@ CREATE TABLE t_numeric (id INT, val DECIMAL(10,2));
 INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
 INSERT INTO t_numeric VALUES (1, 10.50);
 SELECT * FROM t_complex WHERE val > (SELECT AVG(val) FROM t_numeric);
-ERROR HY000: Cannot compare values of custom and non-custom types in >
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in >
 DROP TABLE t_complex;
 DROP TABLE t_numeric;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/r/subquery_cross_type_in.result b/mysql-test/suite/villagesql/implicit_cast/disallowed/r/subquery_cross_type_in.result
@@ -3,6 +3,6 @@ CREATE TABLE t_string (id INT, val VARCHAR(100));
 INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
 INSERT INTO t_string VALUES (1, 'hello');
 SELECT * FROM t_complex WHERE val IN (SELECT val FROM t_string);
-ERROR HY000: Cannot compare values of custom and non-custom types in =
+ERROR HY000: Unable to implicitly cast a non-custom type during compare with a custom type in =
 DROP TABLE t_complex;
 DROP TABLE t_string;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/t/cross_type_comparison_complex_numeric.test b/mysql-test/suite/villagesql/implicit_cast/disallowed/t/cross_type_comparison_complex_numeric.test
@@ -8,10 +8,33 @@ CREATE TABLE t_numeric (id INT, val DECIMAL(10,2));
 INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
 INSERT INTO t_numeric VALUES (1, 10.50);
 
+# Test comparing COMPLEX with DECIMAL column
 --error ER_VILLAGESQL_GENERIC_ERROR
 SELECT * FROM t_complex c, t_numeric n WHERE c.val = n.val;
 
 DROP TABLE t_complex;
 DROP TABLE t_numeric;
 
+# Test comparing COMPLEX with various numeric types in single table
+CREATE TABLE t_mixed (id INT, complex_col COMPLEX, decimal_col DECIMAL(10,2), int_col INT);
+INSERT INTO t_mixed VALUES (1, '(1.0,2.0)', 1.5, 5);
+
+# COMPLEX vs DECIMAL column
+--error ER_VILLAGESQL_GENERIC_ERROR
+SELECT * FROM t_mixed WHERE complex_col = decimal_col;
+
+# COMPLEX vs INT column
+--error ER_VILLAGESQL_GENERIC_ERROR
+SELECT * FROM t_mixed WHERE complex_col = int_col;
+
+# COMPLEX vs INT literal
+--error ER_VILLAGESQL_GENERIC_ERROR
+SELECT * FROM t_mixed WHERE complex_col = 5;
+
+# COMPLEX vs DECIMAL literal
+--error ER_VILLAGESQL_GENERIC_ERROR
+SELECT * FROM t_mixed WHERE complex_col = 1.5;
+
+DROP TABLE t_mixed;
+
 --source include/villagesql/uninstall_complex_extension.inc
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/t/join_mixed_types.test b/mysql-test/suite/villagesql/implicit_cast/disallowed/t/join_mixed_types.test
@@ -1,6 +1,5 @@
 # Test JOIN conditions with mixed types
 
---source include/villagesql/not_implemented_complex_type.inc
 --source include/villagesql/install_complex_extension.inc
 
 CREATE TABLE t_complex (id INT, val COMPLEX);
@@ -9,7 +8,7 @@ CREATE TABLE t_string (id INT, val VARCHAR(100));
 INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
 INSERT INTO t_string VALUES (1, 'hello');
 
---error ER_WRONG_USAGE
+--error ER_VILLAGESQL_GENERIC_ERROR
 SELECT * FROM t_complex c JOIN t_string s ON c.val = s.val;
 
 DROP TABLE t_complex;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/t/left_join_mixed_types.test b/mysql-test/suite/villagesql/implicit_cast/disallowed/t/left_join_mixed_types.test
@@ -1,6 +1,5 @@
 # Test LEFT JOIN with mixed types
 
---source include/villagesql/not_implemented_complex_type.inc
 --source include/villagesql/install_complex_extension.inc
 
 CREATE TABLE t_complex (id INT, val COMPLEX);
@@ -9,6 +8,7 @@ CREATE TABLE t_numeric (id INT, val DECIMAL(10,2));
 INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
 INSERT INTO t_numeric VALUES (1, 10.50);
 
+--error ER_VILLAGESQL_GENERIC_ERROR
 SELECT * FROM t_complex c LEFT JOIN t_numeric n ON c.val = n.val;
 
 DROP TABLE t_complex;
diff --git a/mysql-test/suite/villagesql/implicit_cast/disallowed/t/multi_table_delete_mixed_comparison.test b/mysql-test/suite/villagesql/implicit_cast/disallowed/t/multi_table_delete_mixed_comparison.test
@@ -1,6 +1,5 @@
 # Test multi-table DELETE with mixed comparison
 
---source include/villagesql/not_implemented_complex_type.inc
 --source include/villagesql/install_complex_extension.inc
 
 CREATE TABLE t_complex (id INT, val COMPLEX);
@@ -9,6 +8,7 @@ CREATE TABLE t_string (id INT, val VARCHAR(100));
 INSERT INTO t_complex VALUES (1, '(1.0,2.0)');
 INSERT INTO t_string VALUES (1, 'hello');
 
+--error ER_VILLAGESQL_GENERIC_ERROR
 DELETE c FROM t_complex c, t_string s WHERE c.val = s.val;
 
 DROP TABLE t_complex;
diff --git a/mysql-test/suite/villagesql/select/r/select_custom_type_errors.result b/mysql-test/suite/villagesql/select/r/select_custom_type_errors.result
@@ -2,24 +2,24 @@ CREATE TABLE t1 (id INT, val1 COMPLEX);
 CREATE TABLE t2 (id INT, val2 COMPLEX2);
 INSERT INTO t1 VALUES (1, '(1.0,2.0)'), (2, '(3.0,4.0)');
 SELECT * FROM t1, t2 WHERE t1.val1 = t2.val2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in =
 SELECT * FROM t1, t2 WHERE t1.val1 <> t2.val2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in <>
 SELECT * FROM t1, t2 WHERE t1.val1 < t2.val2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in <
 SELECT * FROM t1, t2 WHERE t1.val1 > t2.val2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in >
 SELECT * FROM t1, t2 WHERE t1.val1 <= t2.val2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in <=
 SELECT * FROM t1, t2 WHERE t1.val1 >= t2.val2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in >=
 SELECT * FROM t1, t2 WHERE t1.val1 <=> t2.val2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in <=>
 CREATE TABLE t3 (id INT, val1 COMPLEX, val2 COMPLEX2);
 SELECT * FROM t3 WHERE val1 = val2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in =
 SELECT * FROM t1 JOIN t2 ON t1.val1 = t2.val2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in =
 SELECT * FROM t1 t1a, t1 t1b WHERE t1a.val1 = t1b.val1;
 id	val1	id	val1
 1	(1,2)	1	(1,2)
@@ -31,7 +31,7 @@ CREATE TABLE t1 (id INT, val1 COMPLEX);
 CREATE TABLE t2 (id INT, val2 COMPLEX2 INVISIBLE);
 INSERT INTO t1 VALUES (1, '(1.0,2.0)'), (2, '(3.0,4.0)');
 SELECT * FROM t1, t2 WHERE t1.val1 = t2.val2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in =
 DROP TABLE t1;
 DROP TABLE t2;
 CREATE TABLE t1 (id INT, val1 COMPLEX);
diff --git a/mysql-test/suite/villagesql/select/r/select_invisible_complex_function.result b/mysql-test/suite/villagesql/select/r/select_invisible_complex_function.result
@@ -1,12 +1,12 @@
 CREATE TABLE t1 (id INT, val1 COMPLEX INVISIBLE, val2 COMPLEX2);
 INSERT INTO t1 (id, val1) VALUES (1, '(1.0,2.0)'), (2, '(3.0,4.0)');
 SELECT id, (val1 = val2) AS are_equal FROM t1;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in =
 DROP TABLE t1;
 CREATE TABLE t2 (id INT, val1 COMPLEX INVISIBLE, val2 COMPLEX2 INVISIBLE);
 INSERT INTO t2 (id, val1) VALUES (1, '(1.0,2.0)'), (2, '(3.0,4.0)');
 SELECT id, (val1 = val2) AS are_equal FROM t2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in =
 DROP TABLE t2;
 CREATE TABLE t3 (val1 COMPLEX INVISIBLE, val2 COMPLEX INVISIBLE);
 ERROR HY000: A table must have at least one visible column.
diff --git a/mysql-test/suite/villagesql/select/r/select_invisible_complex_where.result b/mysql-test/suite/villagesql/select/r/select_invisible_complex_where.result
@@ -2,7 +2,7 @@ CREATE TABLE t1 (id INT, val1 COMPLEX);
 CREATE TABLE t2 (id INT, val2 COMPLEX2 INVISIBLE);
 INSERT INTO t1 VALUES (1, '(1.0,2.0)'), (2, '(3.0,4.0)');
 SELECT * FROM t1, t2 WHERE t1.val1 = t2.val2;
-ERROR HY000: Cannot compare values of incompatible types 'COMPLEX' and 'COMPLEX2'
+ERROR HY000: Cannot compare types vsql_complex.COMPLEX and vsql_complex.COMPLEX2 in =
 DROP TABLE t1;
 DROP TABLE t2;
 CREATE TABLE t1 (id INT, val1 COMPLEX);
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc
@@ -807,26 +807,9 @@ bool Item_func_comparison::fix_fields(THD *thd, Item **ref) {
   // First, fix the fields using parent's implementation
   if (Item_bool_func2::fix_fields(thd, ref)) return true;
 
-  // Check if either side is a custom type
-  Item *lhs = args[0];
-  Item *rhs = args[1];
-  const villagesql::TypeContext *lhs_tc = lhs->get_type_context();
-  const villagesql::TypeContext *rhs_tc = rhs->get_type_context();
-
-  // If neither side is custom, nothing to do
-  if (lhs_tc == nullptr && rhs_tc == nullptr) return false;
-
-  // If both sides are custom, leave compatibility checking for later
-  if (lhs_tc != nullptr && rhs_tc != nullptr) {
-    return false;
-  }
-
-  // One side is custom, the other is not. Inject type into the other Item, if
-  // appropriate.
-  const villagesql::TypeContext *tc = (lhs_tc != nullptr) ? lhs_tc : rhs_tc;
-  Item *non_custom_arg = (lhs_tc != nullptr) ? args[1] : args[0];
-
-  return villagesql::TryImplicitCastToCustom(non_custom_arg, *tc);
+  // VillageSQL: Validate and cast custom type comparisons if needed
+  return villagesql::MaybeValidateAndCastCustomTypeComparison(
+      *args[0], *args[1], func_name());
 }
 
 bool Item_func_like::resolve_type(THD *thd) {
diff --git a/villagesql/types/util.cc b/villagesql/types/util.cc
@@ -413,6 +413,48 @@ bool MaybeValidateUnionTypeCompatibility(Item *accumulator, Item *item) {
   return false;  // success
 }
 
+bool MaybeValidateAndCastCustomTypeComparison(Item &left, Item &right,
+                                              const char *operation_name) {
+  const TypeContext *lhs_tc = left.get_type_context();
+  const TypeContext *rhs_tc = right.get_type_context();
+
+  // If neither has a custom type, no validation needed
+  if (lhs_tc == nullptr && rhs_tc == nullptr) {
+    return false;
+  }
+
+  // Case 1: Both sides have custom types
+  if (lhs_tc != nullptr && rhs_tc != nullptr) {
+    if (!AreTypesCompatible(*lhs_tc, *rhs_tc)) {
+      villagesql_error("Cannot compare types %s and %s in %s", MYF(0),
+                       lhs_tc->qualified_name().c_str(),
+                       rhs_tc->qualified_name().c_str(), operation_name);
+      return true;
+    }
+    return false;
+  }
+
+  // Case 2: One side is custom, the other is not
+  const TypeContext *tc = (lhs_tc != nullptr) ? lhs_tc : rhs_tc;
+  Item *non_custom_arg = (lhs_tc != nullptr) ? &right : &left;
+
+  // Try to cast string/null literals to custom type
+  if (TryImplicitCastToCustom(non_custom_arg, *tc)) {
+    return true;  // Error during cast
+  }
+
+  // If still not custom after trying to cast, it's incompatible
+  if (!non_custom_arg->has_type_context()) {
+    villagesql_error(
+        "Unable to implicitly cast a non-custom type during compare with a "
+        "custom type in %s",
+        MYF(0), operation_name);
+    return true;
+  }
+
+  return false;
+}
+
 const TypeContext *GetCompatibleCustomType(const Item &item1,
                                            const Item &item2) {
   bool has_custom1 = item1.has_type_context();
diff --git a/villagesql/types/util.h b/villagesql/types/util.h
@@ -239,6 +239,19 @@ bool AreTypesCompatible(const TypeContext &tc1, const TypeContext &tc2);
 // needed). Returns false on success, true on error (and reports the error).
 bool MaybeValidateUnionTypeCompatibility(Item *accumulator, Item *item);
 
+// Validate and cast custom type comparisons for comparison operators (=, <, >,
+// etc). If neither item has a custom type, returns false immediately (no
+// validation needed). Otherwise:
+// 1. Both have custom types -> check compatibility, error if incompatible
+// 2. One has custom type, other can be implicitly cast -> cast to custom type
+// 3. One has custom type, other cannot be cast -> error
+// Whether an item can be implicitly cast is determined by
+// CanImplicitlyCastToCustom. May modify items (inject type context and encode
+// string literals). Returns false on success, true on error (and reports the
+// error).
+bool MaybeValidateAndCastCustomTypeComparison(Item &left, Item &right,
+                                              const char *operation_name);
+
 // Get custom type context if Items have compatible custom types
 // Returns TypeContext* if one or both Items have compatible custom types
 // Returns nullptr if no custom types or if custom types are incompatible
