Simplify more checks related to set-returning functions

This makes more consistent the SRF-related checks in the area of
PL/pgSQL, PL/Perl, PL/Tcl, pageinspect and some of the JSON worker
functions, making it easier to grep for the same error patterns through
the code, reducing a bit the translation work.

It is worth noting that each_worker_jsonb()/each_worker() in jsonfuncs.c
and pageinspect's brin_page_items() were doing a check on expectedDesc
that is not required as they fetch their tuple descriptor directly from
get_call_result_type().  This looks like a set of copy-paste errors that
have spread over the years.

This commit is a continuation of the changes begun in 07daca5, for any
remaining code paths on sight.  Like fcc2817, this makes the code more
consistent, easing the integration of a larger patch that will refactor
the way tuplestores are created and checked in a good portion of the
set-returning functions present in core.

I have worked my way through the changes of this patch by myself, and
Ranier has proposed the same changes in a different thread in parallel,
though there were some inconsistencies related in expectedDesc in what
was proposed by him.

Author: Michael Paquier, Ranier Vilela
Discussion: https://postgr.es/m/CAAKRu_azyd1Z3W_r7Ou4sorTjRCs+PxeHw1CWJeXKofkE6TuZg@mail.gmail.com
Discussion: https://postgr.es/m/CAEudQApm=AFuJjEHLBjBcJbxcw4pBMwg2sHwXyCXYcbBOj3hpg@mail.gmail.com

1 files changed, 35 insertions, 26 deletions

diff --git a/src/backend/utils/adt/jsonfuncs.c b/src/backend/utils/adt/jsonfuncs.c
index 0273f883d4f..2457061f97e 100644
--- a/src/backend/utils/adt/jsonfuncs.c
+++ b/src/backend/utils/adt/jsonfuncs.c
@@ -1927,21 +1927,19 @@ each_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname, bool as_text)
 
 	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
 
-	if (!rsi || !IsA(rsi, ReturnSetInfo) ||
-		(rsi->allowedModes & SFRM_Materialize) == 0 ||
-		rsi->expectedDesc == NULL)
+	if (!rsi || !IsA(rsi, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+	if (!(rsi->allowedModes & SFRM_Materialize))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that "
-						"cannot accept a set")));
+				 errmsg("materialize mode required, but it is not allowed in this context")));
 
 	rsi->returnMode = SFRM_Materialize;
 
 	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
-		ereport(ERROR,
-				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("function returning record called in context "
-						"that cannot accept type record")));
+		elog(ERROR, "return type must be a row type");
 
 	old_cxt = MemoryContextSwitchTo(rsi->econtext->ecxt_per_query_memory);
 
@@ -2039,13 +2037,15 @@ each_worker(FunctionCallInfo fcinfo, bool as_text)
 
 	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
 
-	if (!rsi || !IsA(rsi, ReturnSetInfo) ||
-		(rsi->allowedModes & SFRM_Materialize) == 0 ||
-		rsi->expectedDesc == NULL)
+	if (!rsi || !IsA(rsi, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+
+	if (!(rsi->allowedModes & SFRM_Materialize))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that "
-						"cannot accept a set")));
+				 errmsg("materialize mode required, but it is not allowed in this context")));
 
 	rsi->returnMode = SFRM_Materialize;
 
@@ -2227,13 +2227,16 @@ elements_worker_jsonb(FunctionCallInfo fcinfo, const char *funcname,
 
 	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
 
-	if (!rsi || !IsA(rsi, ReturnSetInfo) ||
-		(rsi->allowedModes & SFRM_Materialize) == 0 ||
+	if (!rsi || !IsA(rsi, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+
+	if (!(rsi->allowedModes & SFRM_Materialize) ||
 		rsi->expectedDesc == NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that "
-						"cannot accept a set")));
+				 errmsg("materialize mode required, but it is not allowed in this context")));
 
 	rsi->returnMode = SFRM_Materialize;
 
@@ -2336,13 +2339,16 @@ elements_worker(FunctionCallInfo fcinfo, const char *funcname, bool as_text)
 
 	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
 
-	if (!rsi || !IsA(rsi, ReturnSetInfo) ||
-		(rsi->allowedModes & SFRM_Materialize) == 0 ||
+	if (!rsi || !IsA(rsi, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+
+	if (!(rsi->allowedModes & SFRM_Materialize) ||
 		rsi->expectedDesc == NULL)
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that "
-						"cannot accept a set")));
+				 errmsg("materialize mode required, but it is not allowed in this context")));
 
 	rsi->returnMode = SFRM_Materialize;
 
@@ -3798,12 +3804,15 @@ populate_recordset_worker(FunctionCallInfo fcinfo, const char *funcname,
 
 	rsi = (ReturnSetInfo *) fcinfo->resultinfo;
 
-	if (!rsi || !IsA(rsi, ReturnSetInfo) ||
-		(rsi->allowedModes & SFRM_Materialize) == 0)
+	if (!rsi || !IsA(rsi, ReturnSetInfo))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("set-valued function called in context that cannot accept a set")));
+
+	if (!(rsi->allowedModes & SFRM_Materialize))
 		ereport(ERROR,
 				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-				 errmsg("set-valued function called in context that "
-						"cannot accept a set")));
+				 errmsg("materialize mode required, but it is not allowed in this context")));
 
 	rsi->returnMode = SFRM_Materialize;