Add more assertions in palloc0() and palloc_extended()

palloc() includes an assertion checking that an alloc() implementation
never returns NULL for all MemoryContextMethods.

This commit adds a similar assertion in palloc0().  In palloc_extend(),
a different assertion is added, checking that MCXT_ALLOC_NO_OOM is set
when an alloc() routine returns NULL.  These additions can be useful to
catch errors when implementing a new set of MemoryContextMethods
routines.

Author: Andreas Karlsson <[email protected]>
Discussion: https://postgr.es/m/507e8eba-2035-4a12-a777-98199a66beb8@proxel.se

diff --git a/src/backend/utils/mmgr/mcxt.c b/src/backend/utils/mmgr/mcxt.c
index aa6da0d0352ae366031a4d1b915a1dafdaebea1c..91060de0ab7a81c370abe0e55a45c4f567f75c27 100644 (file)
--- a/src/backend/utils/mmgr/mcxt.c
+++ b/src/backend/utils/mmgr/mcxt.c
@@ -1356,7 +1356,8 @@ palloc0(Size size)
    context->isReset = false;
 
    ret = context->methods->alloc(context, size, 0);
-
+   /* We expect OOM to be handled by the alloc function */
+   Assert(ret != NULL);
    VALGRIND_MEMPOOL_ALLOC(context, ret, size);
 
    MemSetAligned(ret, 0, size);
@@ -1379,6 +1380,8 @@ palloc_extended(Size size, int flags)
    ret = context->methods->alloc(context, size, flags);
    if (unlikely(ret == NULL))
    {
+       /* NULL can be returned only when using MCXT_ALLOC_NO_OOM */
+       Assert(flags & MCXT_ALLOC_NO_OOM);
        return NULL;
    }