database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-02 09:02:37 +03:00
Code Activity

Track nesting depth correctly when drilling down into RECORD Vars.

Browse Source 
expandRecordVariable() failed to adjust the parse nesting structure
correctly when recursing to inspect an outer-level Var.  This could
result in assertion failures or core dumps in corner cases.

Likewise, get_name_for_var_field() failed to adjust the deparse
namespace stack correctly when recursing to inspect an outer-level
Var.  In this case the likely result was a "bogus varno" error
while deparsing a view.

Per bug #18077 from Jingzhou Fu.  Back-patch to all supported
branches.

Richard Guo, with some adjustments by me

Discussion: https://postgr.es/m/18077-b9db97c6e0ab45d8@postgresql.org
This commit is contained in:
Tom Lane
2023-09-15 17:01:26 -04:00
parent 3f94dfc008
commit 53630f12d3
4 changed files with 121 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

41
src/backend/utils/adt/ruleutils.c
View File

@ -7806,22 +7806,28 @@ get_name_for_var_field(Var *var, int fieldno,
* Recurse into the sub-select to see what its Var
* refers to. We have to build an additional level of
* namespace to keep in step with varlevelsup in the
* subselect.
* subselect; furthermore, the subquery RTE might be
* from an outer query level, in which case the
* namespace for the subselect must have that outer
* level as parent namespace.
*/
List *save_nslist = context->namespaces;
List *parent_namespaces;
deparse_namespace mydpns;
const char *result;
set_deparse_for_query(&mydpns, rte->subquery,
context->namespaces);
parent_namespaces = list_copy_tail(context->namespaces,
netlevelsup);
context->namespaces = lcons(&mydpns,
context->namespaces);
set_deparse_for_query(&mydpns, rte->subquery,
parent_namespaces);
context->namespaces = lcons(&mydpns, parent_namespaces);
result = get_name_for_var_field((Var *) expr, fieldno,
0, context);
context->namespaces =
list_delete_first(context->namespaces);
context->namespaces = save_nslist;
return result;
}
@ -7913,7 +7919,7 @@ get_name_for_var_field(Var *var, int fieldno,
attnum);
if (ste == NULL || ste->resjunk)
elog(ERROR, "subquery %s does not have attribute %d",
elog(ERROR, "CTE %s does not have attribute %d",
rte->eref->aliasname, attnum);
expr = (Node *) ste->expr;
if (IsA(expr, Var))
@ -7921,21 +7927,22 @@ get_name_for_var_field(Var *var, int fieldno,
/*
* Recurse into the CTE to see what its Var refers to.
* We have to build an additional level of namespace
* to keep in step with varlevelsup in the CTE.
* Furthermore it could be an outer CTE, so we may
* have to delete some levels of namespace.
* to keep in step with varlevelsup in the CTE;
* furthermore it could be an outer CTE (compare
* SUBQUERY case above).
*/
List *save_nslist = context->namespaces;
List *new_nslist;
List *parent_namespaces;
deparse_namespace mydpns;
const char *result;
set_deparse_for_query(&mydpns, ctequery,
context->namespaces);
parent_namespaces = list_copy_tail(context->namespaces,
ctelevelsup);
new_nslist = list_copy_tail(context->namespaces,
ctelevelsup);
context->namespaces = lcons(&mydpns, new_nslist);
set_deparse_for_query(&mydpns, ctequery,
parent_namespaces);
context->namespaces = lcons(&mydpns, parent_namespaces);
result = get_name_for_var_field((Var *) expr, fieldno,
0, context);