diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2024-11-25 18:08:58 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2024-11-25 18:09:09 -0500 |
| commit | 5b8728cd7f9d3d93b6ff9b48887084fdf0a46e4f (patch) | |
| tree | b62eee91b8fa0d602753987f1a1c00aa0b7bb01f /src/test | |
| parent | 4ba84de459532a7a79616e756f8bfd45ba4b8048 (diff) | |
Fix NULLIF()'s handling of read-write expanded objects.
If passed a read-write expanded object pointer, the EEOP_NULLIF
code would hand that same pointer to the equality function
and then (unless equality was reported) also return the same
pointer as its value. This is no good, because a function that
receives a read-write expanded object pointer is fully entitled
to scribble on or even delete the object, thus corrupting the
NULLIF output. (This problem is likely unobservable with the
equality functions provided in core Postgres, but it's easy to
demonstrate with one coded in plpgsql.)
To fix, make sure the pointer passed to the equality function
is read-only. We can still return the original read-write
pointer as the NULLIF result, allowing optimization of later
operations.
Per bug #18722 from Alexander Lakhin. This has been wrong
since we invented expanded objects, so back-patch to all
supported branches.
Discussion: https://postgr.es/m/18722-fd9e645448cc78b4@postgresql.org
Diffstat (limited to 'src/test')
| -rw-r--r-- | src/test/regress/expected/case.out | 8 | ||||
| -rw-r--r-- | src/test/regress/sql/case.sql | 5 |
2 files changed, 13 insertions, 0 deletions
diff --git a/src/test/regress/expected/case.out b/src/test/regress/expected/case.out index f5136c17abb..efee7fc4317 100644 --- a/src/test/regress/expected/case.out +++ b/src/test/regress/expected/case.out @@ -397,6 +397,14 @@ SELECT CASE make_ad(1,2) right (1 row) +-- While we're here, also test handling of a NULLIF arg that is a read/write +-- object (bug #18722) +SELECT NULLIF(make_ad(1,2), array[2,3]::arrdomain); + nullif +-------- + {1,2} +(1 row) + ROLLBACK; -- Test interaction of CASE with ArrayCoerceExpr (bug #15471) BEGIN; diff --git a/src/test/regress/sql/case.sql b/src/test/regress/sql/case.sql index 83fe43be6b8..388d4c6f528 100644 --- a/src/test/regress/sql/case.sql +++ b/src/test/regress/sql/case.sql @@ -242,6 +242,11 @@ SELECT CASE make_ad(1,2) WHEN array[1,2]::arrdomain THEN 'right' END; +-- While we're here, also test handling of a NULLIF arg that is a read/write +-- object (bug #18722) + +SELECT NULLIF(make_ad(1,2), array[2,3]::arrdomain); + ROLLBACK; -- Test interaction of CASE with ArrayCoerceExpr (bug #15471) |