Use more detailed message in record insert error.

Maxim Orlov · Maxim Orlov · commit 6a62ec605b5b · 2020-12-08T10:01:39.000+03:00
In case of inserting a erroneous record in variable show clear messages, if it is
amount of fields or fields types are wrong.
diff --git a/expected/pg_variables.out b/expected/pg_variables.out
@@ -563,11 +563,11 @@ ERROR:  variable "j1" requires "jsonb" value
 SELECT pgv_insert('vars3', 'r1', tab) FROM tab;
 ERROR:  there is a record in the variable "r1" with same key
 SELECT pgv_insert('vars3', 'r1', row(1, 'str1', 'str2'));
-ERROR:  new record structure differs from variable "r1" structure
+ERROR:  new record structure have 3 attributes, but variable "r1" structure have 2.
 SELECT pgv_insert('vars3', 'r1', row(1, 1));
-ERROR:  new record structure differs from variable "r1" structure
+ERROR:  new record attribute type for attribute number 2 differs from variable "r1" structure. You may need explicit type casts.
 SELECT pgv_insert('vars3', 'r1', row('str1', 'str1'));
-ERROR:  new record structure differs from variable "r1" structure
+ERROR:  new record attribute type for attribute number 1 differs from variable "r1" structure. You may need explicit type casts.
 SELECT pgv_select('vars3', 'r1', ARRAY[[1,2]]); -- fail
 ERROR:  searching for elements in multidimensional arrays is not supported
 -- Test variables caching
diff --git a/pg_variables_record.c b/pg_variables_record.c
@@ -188,8 +188,9 @@ check_attributes(Variable *variable, TupleDesc tupdesc)
 	if (record->tupdesc->natts != tupdesc->natts)
 		ereport(ERROR,
 				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("new record structure differs from variable \"%s\" "
-						"structure", GetName(variable))));
+				 errmsg("new record structure have %d attributes, but variable "
+						"\"%s\" structure have %d.",
+						tupdesc->natts, GetName(variable), record->tupdesc->natts)));
 
 	/* Second, check columns type. */
 	for (i = 0; i < tupdesc->natts; i++)
@@ -202,8 +203,10 @@ check_attributes(Variable *variable, TupleDesc tupdesc)
 			|| (attr1->atttypmod != attr2->atttypmod))
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-					 errmsg("new record structure differs from variable \"%s\" "
-							"structure", GetName(variable))));
+					 errmsg("new record attribute type for attribute number %d "
+							"differs from variable \"%s\" structure. You may "
+							"need explicit type casts.",
+							i + 1, GetName(variable))));
 	}
 }
 
