diff options
Diffstat (limited to 'src/backend/commands/tablecmds.c')
| -rw-r--r-- | src/backend/commands/tablecmds.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c index 463d2506c2e..36162758583 100644 --- a/src/backend/commands/tablecmds.c +++ b/src/backend/commands/tablecmds.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.136 2004/10/21 21:33:59 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.137 2004/10/22 17:20:04 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -4738,13 +4738,20 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel, * changing the column type, because build_column_default itself will * try to coerce, and will not issue the error message we want if it * fails.) + * + * We remove any implicit coercion steps at the top level of the old + * default expression; this has been agreed to satisfy the principle + * of least surprise. (The conversion to the new column type should + * act like it started from what the user sees as the stored expression, + * and the implicit coercions aren't going to be shown.) */ if (attTup->atthasdef) { defaultexpr = build_column_default(rel, attnum); Assert(defaultexpr); + defaultexpr = strip_implicit_coercions(defaultexpr); defaultexpr = coerce_to_target_type(NULL, /* no UNKNOWN params */ - defaultexpr, exprType(defaultexpr), + defaultexpr, exprType(defaultexpr), targettype, typename->typmod, COERCION_ASSIGNMENT, COERCE_IMPLICIT_CAST); |