From f026c16a2c5a3ee5d7aa6f85333ec80c905913ba Mon Sep 17 00:00:00 2001 From: Dean Rasheed Date: Tue, 10 Jan 2023 14:17:47 +0000 Subject: [PATCH] Fix MERGE's test for unreachable WHEN clauses. The former code would only detect an unreachable WHEN clause if it had an AND condition. Fix, so that unreachable unconditional WHEN clauses are also detected. Back-patch to v15, where MERGE was added. Discussion: https://postgr.es/m/CAEZATCVQ=7E2z4cSBB49jjeGGsB6WeoYQY32NDeSvcHiLUZ=ow@mail.gmail.com --- src/backend/parser/parse_merge.c | 6 +++--- src/test/regress/expected/merge.out | 2 +- src/test/regress/sql/merge.sql | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/src/backend/parser/parse_merge.c b/src/backend/parser/parse_merge.c index 611dfce1d6..d8866373b8 100644 --- a/src/backend/parser/parse_merge.c +++ b/src/backend/parser/parse_merge.c @@ -155,12 +155,12 @@ transformMergeStmt(ParseState *pstate, MergeStmt *stmt) /* * Check for unreachable WHEN clauses */ - if (mergeWhenClause->condition == NULL) - is_terminal[when_type] = true; - else if (is_terminal[when_type]) + if (is_terminal[when_type]) ereport(ERROR, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("unreachable WHEN clause specified after unconditional WHEN clause"))); + if (mergeWhenClause->condition == NULL) + is_terminal[when_type] = true; } /* diff --git a/src/test/regress/expected/merge.out b/src/test/regress/expected/merge.out index 6c8a18f7b5..bc53b2105b 100644 --- a/src/test/regress/expected/merge.out +++ b/src/test/regress/expected/merge.out @@ -659,7 +659,7 @@ USING source AS s ON t.tid = s.sid WHEN MATCHED THEN /* Terminal WHEN clause for MATCHED */ DELETE -WHEN MATCHED AND s.delta > 0 THEN +WHEN MATCHED THEN UPDATE SET balance = t.balance - s.delta; ERROR: unreachable WHEN clause specified after unconditional WHEN clause ROLLBACK; diff --git a/src/test/regress/sql/merge.sql b/src/test/regress/sql/merge.sql index 98fe1040bd..fdbcd70882 100644 --- a/src/test/regress/sql/merge.sql +++ b/src/test/regress/sql/merge.sql @@ -438,7 +438,7 @@ USING source AS s ON t.tid = s.sid WHEN MATCHED THEN /* Terminal WHEN clause for MATCHED */ DELETE -WHEN MATCHED AND s.delta > 0 THEN +WHEN MATCHED THEN UPDATE SET balance = t.balance - s.delta; ROLLBACK;