From e0df80828abc0c01fcde123389032370b98f2015 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 15 Apr 2024 12:56:56 -0400 Subject: [PATCH] Fix type-checking of RECORD-returning functions in FROM, redux. Commit 2ed8f9a01 intended to institute a policy that if a RangeTblFunction has a coldeflist, then the function return type is certainly RECORD, and we should use the coldeflist as the source of truth about what the columns of the record type are. When the original function has been folded to a constant, inspection of the constant might give a different answer. This situation will lead to a tuple-type-mismatch error at execution, but up until that point we need to consistently believe the coldeflist, or we'll have problems from different bits of code reaching different conclusions. expandRTE didn't get that memo though, and would try to produce a tupdesc based on the constant in this situation, leading to an assertion failure. (Desultory testing suggests that non-assert builds often manage to give the expected error, although I also saw a "cache lookup failed for type 0" error, and it seems at least possible that a crash could happen.) Some other callers of get_expr_result_type and get_expr_result_tupdesc were also being incautious about this. While none of them seem to have actual bugs, they're working harder than necessary in this case, besides which it seems safest to have an explicit policy of not using those functions on an RTE with a coldeflist. Adjust the code accordingly, and add commentary to funcapi.c about this policy. Also fix an obsolete comment that claimed "get_expr_result_type() doesn't know how to extract type info from a RECORD constant". That hasn't been true since commit d57534740. Per bug #18422 from Alexander Lakhin. As with the previous commit, back-patch to all supported branches. Discussion: https://postgr.es/m/18422-89ca86c8eac5246d@postgresql.org --- src/backend/catalog/dependency.c | 6 +++++- src/backend/optimizer/prep/prepjointree.c | 4 ++++ src/backend/optimizer/util/clauses.c | 11 +++++------ src/backend/parser/parse_relation.c | 19 ++++++++++++++----- src/backend/utils/fmgr/funcapi.c | 10 +++++++++- src/test/regress/expected/rangefuncs.out | 3 +++ src/test/regress/sql/rangefuncs.sql | 1 + 7 files changed, 41 insertions(+), 13 deletions(-) diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c index 6e8f6a5705..d4b5b2ade1 100644 --- a/src/backend/catalog/dependency.c +++ b/src/backend/catalog/dependency.c @@ -2337,7 +2337,11 @@ process_function_rte_ref(RangeTblEntry *rte, AttrNumber attnum, { TupleDesc tupdesc; - tupdesc = get_expr_result_tupdesc(rtfunc->funcexpr, true); + /* If it has a coldeflist, it certainly returns RECORD */ + if (rtfunc->funccolnames != NIL) + tupdesc = NULL; /* no need to work hard */ + else + tupdesc = get_expr_result_tupdesc(rtfunc->funcexpr, true); if (tupdesc && tupdesc->tdtypeid != RECORDOID) { /* diff --git a/src/backend/optimizer/prep/prepjointree.c b/src/backend/optimizer/prep/prepjointree.c index 4badb6ff58..fb768ad52c 100644 --- a/src/backend/optimizer/prep/prepjointree.c +++ b/src/backend/optimizer/prep/prepjointree.c @@ -1854,6 +1854,10 @@ pull_up_constant_function(PlannerInfo *root, Node *jtnode, if (rtf->funccolcount != 1) return jtnode; /* definitely composite */ + /* If it has a coldeflist, it certainly returns RECORD */ + if (rtf->funccolnames != NIL) + return jtnode; /* must be a one-column RECORD type */ + functypclass = get_expr_result_type(rtf->funcexpr, &funcrettype, &tupdesc); diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index b50fe58d1c..59487cbd79 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -4431,12 +4431,11 @@ evaluate_function(Oid funcid, Oid result_type, int32 result_typmod, * Can't simplify if it returns RECORD. The immediate problem is that it * will be needing an expected tupdesc which we can't supply here. * - * In the case where it has OUT parameters, it could get by without an - * expected tupdesc, but we still have issues: get_expr_result_type() - * doesn't know how to extract type info from a RECORD constant, and in - * the case of a NULL function result there doesn't seem to be any clean - * way to fix that. In view of the likelihood of there being still other - * gotchas, seems best to leave the function call unreduced. + * In the case where it has OUT parameters, we could build an expected + * tupdesc from those, but there may be other gotchas lurking. In + * particular, if the function were to return NULL, we would produce a + * null constant with no remaining indication of which concrete record + * type it is. For now, seems best to leave the function call unreduced. */ if (funcform->prorettype == RECORDOID) return NULL; diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c index 7ca793a369..2f64eaf0e3 100644 --- a/src/backend/parser/parse_relation.c +++ b/src/backend/parser/parse_relation.c @@ -2738,12 +2738,17 @@ expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up, { RangeTblFunction *rtfunc = (RangeTblFunction *) lfirst(lc); TypeFuncClass functypclass; - Oid funcrettype; - TupleDesc tupdesc; + Oid funcrettype = InvalidOid; + TupleDesc tupdesc = NULL; + + /* If it has a coldeflist, it returns RECORD */ + if (rtfunc->funccolnames != NIL) + functypclass = TYPEFUNC_RECORD; + else + functypclass = get_expr_result_type(rtfunc->funcexpr, + &funcrettype, + &tupdesc); - functypclass = get_expr_result_type(rtfunc->funcexpr, - &funcrettype, - &tupdesc); if (functypclass == TYPEFUNC_COMPOSITE || functypclass == TYPEFUNC_COMPOSITE_DOMAIN) { @@ -3369,6 +3374,10 @@ get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum) { TupleDesc tupdesc; + /* If it has a coldeflist, it returns RECORD */ + if (rtfunc->funccolnames != NIL) + return false; /* can't have any dropped columns */ + tupdesc = get_expr_result_tupdesc(rtfunc->funcexpr, true); if (tupdesc) diff --git a/src/backend/utils/fmgr/funcapi.c b/src/backend/utils/fmgr/funcapi.c index 5c03704ef9..05d763fa06 100644 --- a/src/backend/utils/fmgr/funcapi.c +++ b/src/backend/utils/fmgr/funcapi.c @@ -287,6 +287,13 @@ get_call_result_type(FunctionCallInfo fcinfo, /* * get_expr_result_type * As above, but work from a calling expression node tree + * + * Beware of using this on the funcexpr of a RTE that has a coldeflist. + * The correct conclusion in such cases is always that the function returns + * RECORD with the columns defined by the coldeflist fields (funccolnames etc). + * If it does not, it's the executor's responsibility to catch the discrepancy + * at runtime; but code processing the query in advance of that point might + * come to inconsistent conclusions if it checks the actual expression. */ TypeFuncClass get_expr_result_type(Node *expr, @@ -537,7 +544,8 @@ internal_get_result_type(Oid funcid, * if noError is true, else throws error. * * This is a simpler version of get_expr_result_type() for use when the caller - * is only interested in determinate rowtype results. + * is only interested in determinate rowtype results. As with that function, + * beware of using this on the funcexpr of a RTE that has a coldeflist. */ TupleDesc get_expr_result_tupdesc(Node *expr, bool noError) diff --git a/src/test/regress/expected/rangefuncs.out b/src/test/regress/expected/rangefuncs.out index 2bda957f43..397a8b35d6 100644 --- a/src/test/regress/expected/rangefuncs.out +++ b/src/test/regress/expected/rangefuncs.out @@ -2498,3 +2498,6 @@ with a(b) as (values (row(1,2,3))) select * from a, coalesce(b) as c(d int, e int, f float); -- fail ERROR: function return row and query-specified return row do not match DETAIL: Returned type integer at ordinal position 3, but query expects double precision. +select * from int8_tbl, coalesce(row(1)) as (a int, b int); -- fail +ERROR: function return row and query-specified return row do not match +DETAIL: Returned row contains 1 attribute, but query expects 2. diff --git a/src/test/regress/sql/rangefuncs.sql b/src/test/regress/sql/rangefuncs.sql index 06d598c5e9..3c47c98e11 100644 --- a/src/test/regress/sql/rangefuncs.sql +++ b/src/test/regress/sql/rangefuncs.sql @@ -824,3 +824,4 @@ with a(b) as (values (row(1,2,3))) select * from a, coalesce(b) as c(d int, e int, f int, g int); -- fail with a(b) as (values (row(1,2,3))) select * from a, coalesce(b) as c(d int, e int, f float); -- fail +select * from int8_tbl, coalesce(row(1)) as (a int, b int); -- fail