Fix parse_cte.c's failure to examine sub-WITHs in DML statements. makeDependencyGraphWalker thought that only SelectStmt nodes could contain a WithClause. Which was true in our original implementation of WITH, but astonishingly we missed updating this code when we added the ability to attach WITH to INSERT/UPDATE/DELETE (and later MERGE). Moreover, since it was coded to deliberately block recursion to a WithClause, even updating raw_expression_tree_walker didn't save it.
The upshot of this was that we didn't see references to outer CTE names appearing within an inner WITH, and would neither complain about disallowed recursion nor account for such references when sorting CTEs into a usable order. The lack of complaints about this is perhaps not so surprising, because typical usage of WITH wouldn't hit either case. Still, it's pretty broken; failing to detect recursion here leads to assert failures or worse later on. Fix by factoring out the processing of sub-WITHs into a new function WalkInnerWith, and invoking that for all the statement types that can have WITH. Bug: #18878 Reported-by: Yu Liang <lu...@psu.edu> Author: Tom Lane <t...@sss.pgh.pa.us> Discussion: https://postgr.es/m/18878-a26fa5ab6be2f...@postgresql.org Backpatch-through: 13 Branch ------ REL_16_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/1980ec2bc99361bb6486bf1aaa836c95dd5d629e Modified Files -------------- src/backend/parser/parse_cte.c | 152 ++++++++++++++++++++++++++----------- src/test/regress/expected/with.out | 8 ++ src/test/regress/sql/with.sql | 7 ++ 3 files changed, 124 insertions(+), 43 deletions(-)
