Simplify GetOperatorFromCompareType() code

The old code would set *opid = InvalidOid to determine if the
get_opclass_opfamily_and_input_type() worked or not.  This means more
moving parts that what's really needed here.  Let's just fail
immediately if the get_opclass_opfamily_and_input_type() lookup fails.

Author: Paul A Jungwirth <pj@illuminatedcomputing.com>
Reviewed-by: Neil Chen <carpenter.nail.cz@gmail.com>
Discussion: https://postgr.es/m/CA+renyXOrjLacP_nhqEQUf2W+ZCoY2q5kpQCfG05vQVYzr8b9w@mail.gmail.com

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 0a7b6f18fa28373bc4d7f032acfe00c6a9d4c47e..08c86cc163c6a2c083d16dee6e4904593ec38514 100644 (file)
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -2473,34 +2473,36 @@ GetOperatorFromCompareType(Oid opclass, Oid rhstype, CompareType cmptype,
 
    Assert(cmptype == COMPARE_EQ || cmptype == COMPARE_OVERLAP || cmptype == COMPARE_CONTAINED_BY);
 
-   amid = get_opclass_method(opclass);
+   /*
+    * Use the opclass to get the opfamily, opcintype, and access method. If
+    * any of this fails, quit early.
+    */
+   if (!get_opclass_opfamily_and_input_type(opclass, &opfamily, &opcintype))
+       elog(ERROR, "cache lookup failed for opclass %u", opclass);
 
-   *opid = InvalidOid;
+   amid = get_opclass_method(opclass);
 
-   if (get_opclass_opfamily_and_input_type(opclass, &opfamily, &opcintype))
-   {
-       /*
-        * Ask the index AM to translate to its internal stratnum
-        */
-       *strat = IndexAmTranslateCompareType(cmptype, amid, opfamily, true);
-       if (*strat == InvalidStrategy)
-           ereport(ERROR,
-                   errcode(ERRCODE_UNDEFINED_OBJECT),
-                   cmptype == COMPARE_EQ ? errmsg("could not identify an equality operator for type %s", format_type_be(opcintype)) :
-                   cmptype == COMPARE_OVERLAP ? errmsg("could not identify an overlaps operator for type %s", format_type_be(opcintype)) :
-                   cmptype == COMPARE_CONTAINED_BY ? errmsg("could not identify a contained-by operator for type %s", format_type_be(opcintype)) : 0,
-                   errdetail("Could not translate compare type %d for operator family \"%s\" of access method \"%s\".",
-                             cmptype, get_opfamily_name(opfamily, false), get_am_name(amid)));
+   /*
+    * Ask the index AM to translate to its internal stratnum
+    */
+   *strat = IndexAmTranslateCompareType(cmptype, amid, opfamily, true);
+   if (*strat == InvalidStrategy)
+       ereport(ERROR,
+               errcode(ERRCODE_UNDEFINED_OBJECT),
+               cmptype == COMPARE_EQ ? errmsg("could not identify an equality operator for type %s", format_type_be(opcintype)) :
+               cmptype == COMPARE_OVERLAP ? errmsg("could not identify an overlaps operator for type %s", format_type_be(opcintype)) :
+               cmptype == COMPARE_CONTAINED_BY ? errmsg("could not identify a contained-by operator for type %s", format_type_be(opcintype)) : 0,
+               errdetail("Could not translate compare type %d for operator family \"%s\" of access method \"%s\".",
+                         cmptype, get_opfamily_name(opfamily, false), get_am_name(amid)));
 
-       /*
-        * We parameterize rhstype so foreign keys can ask for a <@ operator
-        * whose rhs matches the aggregate function. For example range_agg
-        * returns anymultirange.
-        */
-       if (!OidIsValid(rhstype))
-           rhstype = opcintype;
-       *opid = get_opfamily_member(opfamily, opcintype, rhstype, *strat);
-   }
+   /*
+    * We parameterize rhstype so foreign keys can ask for a <@ operator whose
+    * rhs matches the aggregate function. For example range_agg returns
+    * anymultirange.
+    */
+   if (!OidIsValid(rhstype))
+       rhstype = opcintype;
+   *opid = get_opfamily_member(opfamily, opcintype, rhstype, *strat);
 
    if (!OidIsValid(*opid))
        ereport(ERROR,