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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2025-04-05 12:13:35 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2025-04-05 12:13:35 -0400 |
| commit | e33f2335a9d9754ccf3bf7181085cfa581ee03c3 (patch) | |
| tree | 0f0525c6d9937cb892fa2dee4ee30c15c5d41606 /src/backend/parser/parse_expr.c | |
| parent | 5db3bf7391d77ae86bc9b5f580141e022803b744 (diff) | |
| download | postgresql-e33f2335a9d9754ccf3bf7181085cfa581ee03c3.tar.gz postgresql-e33f2335a9d9754ccf3bf7181085cfa581ee03c3.zip | |
Avoid double transformation of json_array()'s subquery.
transformJsonArrayQueryConstructor() applied transformStmt() to
the same subquery tree twice. While this causes no issue in many
cases, there are some where it causes a coredump, thanks to the
parser's habit of scribbling on its input.
Fix by making a copy before the first transformation (compare
0f43083d1). This is quite brute-force, but then so is the
whole business of transforming the input twice. Per discussion
in the bug thread, this implementation of json_array() parsing
should be replaced completely. But that will take some work
and will surely not be back-patchable, so for the moment let's
take the easy way out.
Oversight in 7081ac46a. Back-patch to v16 where that came in.
Bug: #18877
Reported-by: Yu Liang <luy70@psu.edu>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/18877-c3c3ad75845833bb@postgresql.org
Backpatch-through: 16
Diffstat (limited to 'src/backend/parser/parse_expr.c')
| -rw-r--r-- | src/backend/parser/parse_expr.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index 9caf1e481a2..bc602f00ae3 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -3772,7 +3772,7 @@ transformJsonArrayQueryConstructor(ParseState *pstate, /* Transform query only for counting target list entries. */ qpstate = make_parsestate(pstate); - query = transformStmt(qpstate, ctor->query); + query = transformStmt(qpstate, copyObject(ctor->query)); if (count_nonjunk_tlist_entries(query->targetList) != 1) ereport(ERROR, |