In ALTER COLUMN TYPE, strip any implicit coercion operations appearing

at the top level of the column's old default expression before adding
an implicit coercion to the new column type.  This seems to satisfy the
principle of least surprise, as per discussion of bug #1290.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/include/optimizer/clauses.h b/src/include/optimizer/clauses.h
index d3fec6c444c..0f452755e5a 100644
--- a/src/include/optimizer/clauses.h
+++ b/src/include/optimizer/clauses.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/clauses.h,v 1.75 2004/08/29 04:13:07 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/clauses.h,v 1.76 2004/10/22 17:20:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -63,6 +63,8 @@ extern bool has_distinct_on_clause(Query *query);
 extern int	NumRelids(Node *clause);
 extern void CommuteClause(OpExpr *clause);
 
+extern Node *strip_implicit_coercions(Node *node);
+
 extern void set_coercionform_dontcare(Node *node);
 
 extern Node *eval_const_expressions(Node *node);