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authorPeter Eisentraut <peter@eisentraut.org>2024-08-29 08:38:29 +0200
committerPeter Eisentraut <peter@eisentraut.org>2024-08-29 09:03:06 +0200
commit1c57ae795b3c0650cbac13e0f59f326ddc34c5d0 (patch)
tree81f6a25a0ffd647ee1f804a191a08ac0cec873d0 /src/backend/commands/tablecmds.c
parent5ff394503ce2b5b63239ec23fcaca1dc1d1ff049 (diff)
Disallow USING clause when altering type of generated column
This does not make sense. It would write the output of the USING clause into the converted column, which would violate the generation expression. This adds a check to error out if this is specified. There was a test for this, but that test errored out for a different reason, so it was not effective. Reported-by: Jian He <jian.universality@gmail.com> Reviewed-by: Yugo NAGATA <nagata@sraoss.co.jp> Discussion: https://www.postgresql.org/message-id/flat/c7083982-69f4-4b14-8315-f9ddb20b9834%40eisentraut.org
Diffstat (limited to 'src/backend/commands/tablecmds.c')
-rw-r--r--src/backend/commands/tablecmds.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index d3d9e2a89b4..78d529c22c0 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -10954,6 +10954,16 @@ ATPrepAlterColumnType(List **wqueue,
colName)));
/*
+ * Cannot specify USING when altering type of a generated column, because
+ * that would violate the generation expression.
+ */
+ if (attTup->attgenerated && def->cooked_default)
+ ereport(ERROR,
+ (errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+ errmsg("cannot specify USING when altering type of generated column"),
+ errdetail("Column \"%s\" is a generated column.", colName)));
+
+ /*
* Don't alter inherited columns. At outer level, there had better not be
* any inherited definition; when recursing, we assume this was checked at
* the parent level (see below).
@@ -11029,11 +11039,12 @@ ATPrepAlterColumnType(List **wqueue,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("column \"%s\" cannot be cast automatically to type %s",
colName, format_type_be(targettype)),
+ !attTup->attgenerated ?
/* translator: USING is SQL, don't translate it */
errhint("You might need to specify \"USING %s::%s\".",
quote_identifier(colName),
format_type_with_typemod(targettype,
- targettypmod))));
+ targettypmod)) : 0));
}
/* Fix collations after all else */