Make the to_reg*() functions accept text not cstring.

Using cstring as the input type was a poor decision, because that's not
really a full-fledged type.  In particular, it lacks implicit coercions
from text or varchar, meaning that usages like to_regproc('foo'||'bar')
wouldn't work; basically the only case that did work without explicit
casting was a simple literal constant argument.

The lack of field complaints about this suggests that hardly anyone
is using these functions, so hopefully fixing it won't cause much of
a compatibility problem.  They've only been there since 9.4, anyway.

Petr Korobeinikov

doc/src/sgml/func.sgml

@@ -16173,7 +16173,7 @@ SELECT collation for ('foo' COLLATE "de_DE");
    <function>to_regoperator</function>, <function>to_regtype</function>,
    <function>to_regnamespace</function>, and <function>to_regrole</function>
    functions translate relation, function, operator, type, schema, and role
-   names to objects of
+   names (given as <type>text</>) to objects of
    type <type>regclass</>, <type>regproc</>, <type>regprocedure</type>,
    <type>regoper</>, <type>regoperator</type>, <type>regtype</>,
    <type>regnamespace</>, and <type>regrole</>

src/backend/utils/adt/regproc.c

@@ -161,7 +161,7 @@ regprocin(PG_FUNCTION_ARGS)
 Datum
 to_regproc(PG_FUNCTION_ARGS)
 {
-	char	   *pro_name = PG_GETARG_CSTRING(0);
+	char	   *pro_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
 	List	   *names;
 	FuncCandidateList clist;
 
@@ -331,7 +331,7 @@ regprocedurein(PG_FUNCTION_ARGS)
 Datum
 to_regprocedure(PG_FUNCTION_ARGS)
 {
-	char	   *pro_name = PG_GETARG_CSTRING(0);
+	char	   *pro_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
 	List	   *names;
 	int			nargs;
 	Oid			argtypes[FUNC_MAX_ARGS];
@@ -620,7 +620,7 @@ regoperin(PG_FUNCTION_ARGS)
 Datum
 to_regoper(PG_FUNCTION_ARGS)
 {
-	char	   *opr_name = PG_GETARG_CSTRING(0);
+	char	   *opr_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
 	List	   *names;
 	FuncCandidateList clist;
 
@@ -797,7 +797,7 @@ regoperatorin(PG_FUNCTION_ARGS)
 Datum
 to_regoperator(PG_FUNCTION_ARGS)
 {
-	char	   *opr_name_or_oid = PG_GETARG_CSTRING(0);
+	char	   *opr_name_or_oid = text_to_cstring(PG_GETARG_TEXT_PP(0));
 	Oid			result;
 	List	   *names;
 	int			nargs;
@@ -1061,7 +1061,7 @@ regclassin(PG_FUNCTION_ARGS)
 Datum
 to_regclass(PG_FUNCTION_ARGS)
 {
-	char	   *class_name = PG_GETARG_CSTRING(0);
+	char	   *class_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
 	Oid			result;
 	List	   *names;
 
@@ -1249,7 +1249,7 @@ regtypein(PG_FUNCTION_ARGS)
 Datum
 to_regtype(PG_FUNCTION_ARGS)
 {
-	char	   *typ_name = PG_GETARG_CSTRING(0);
+	char	   *typ_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
 	Oid			result;
 	int32		typmod;
 
@@ -1606,7 +1606,7 @@ regrolein(PG_FUNCTION_ARGS)
 Datum
 to_regrole(PG_FUNCTION_ARGS)
 {
-	char	   *role_name = PG_GETARG_CSTRING(0);
+	char	   *role_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
 	Oid			result;
 	List	   *names;
 
@@ -1727,7 +1727,7 @@ regnamespacein(PG_FUNCTION_ARGS)
 Datum
 to_regnamespace(PG_FUNCTION_ARGS)
 {
-	char	   *nsp_name = PG_GETARG_CSTRING(0);
+	char	   *nsp_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
 	Oid			result;
 	List	   *names;
 

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201601041
+#define CATALOG_VERSION_NO	201601051
 
 #endif

src/include/catalog/pg_proc.h

@@ -177,9 +177,9 @@ DATA(insert OID =  44 (  regprocin		   PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1
 DESCR("I/O");
 DATA(insert OID =  45 (  regprocout		   PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2275 "24" _null_ _null_ _null_ _null_ _null_ regprocout _null_ _null_ _null_ ));
 DESCR("I/O");
-DATA(insert OID = 3494 (  to_regproc		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 24 "2275" _null_ _null_ _null_ _null_ _null_ to_regproc _null_ _null_ _null_ ));
+DATA(insert OID = 3494 (  to_regproc		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 24 "25" _null_ _null_ _null_ _null_ _null_ to_regproc _null_ _null_ _null_ ));
 DESCR("convert proname to regproc");
-DATA(insert OID = 3479 (  to_regprocedure	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2202 "2275" _null_ _null_ _null_ _null_ _null_ to_regprocedure _null_ _null_ _null_ ));
+DATA(insert OID = 3479 (  to_regprocedure	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2202 "25" _null_ _null_ _null_ _null_ _null_ to_regprocedure _null_ _null_ _null_ ));
 DESCR("convert proname to regprocedure");
 DATA(insert OID =  46 (  textin			   PGNSP PGUID 12 1 0 0 0 f f f f t f i s 1 0 25 "2275" _null_ _null_ _null_ _null_ _null_ textin _null_ _null_ _null_ ));
 DESCR("I/O");
@@ -3483,9 +3483,9 @@ DATA(insert OID = 2214 (  regoperin			PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0
 DESCR("I/O");
 DATA(insert OID = 2215 (  regoperout		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2275 "2203" _null_ _null_ _null_ _null_ _null_ regoperout _null_ _null_ _null_ ));
 DESCR("I/O");
-DATA(insert OID = 3492 (  to_regoper		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2203 "2275" _null_ _null_ _null_ _null_ _null_ to_regoper _null_ _null_ _null_ ));
+DATA(insert OID = 3492 (  to_regoper		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2203 "25" _null_ _null_ _null_ _null_ _null_ to_regoper _null_ _null_ _null_ ));
 DESCR("convert operator name to regoper");
-DATA(insert OID = 3476 (  to_regoperator	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2204 "2275" _null_ _null_ _null_ _null_ _null_ to_regoperator _null_ _null_ _null_ ));
+DATA(insert OID = 3476 (  to_regoperator	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2204 "25" _null_ _null_ _null_ _null_ _null_ to_regoperator _null_ _null_ _null_ ));
 DESCR("convert operator name to regoperator");
 DATA(insert OID = 2216 (  regoperatorin		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2204 "2275" _null_ _null_ _null_ _null_ _null_ regoperatorin _null_ _null_ _null_ ));
 DESCR("I/O");
@@ -3495,13 +3495,13 @@ DATA(insert OID = 2218 (  regclassin		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0
 DESCR("I/O");
 DATA(insert OID = 2219 (  regclassout		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2275 "2205" _null_ _null_ _null_ _null_ _null_ regclassout _null_ _null_ _null_ ));
 DESCR("I/O");
-DATA(insert OID = 3495 (  to_regclass		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2205 "2275" _null_ _null_ _null_ _null_ _null_ to_regclass _null_ _null_ _null_ ));
+DATA(insert OID = 3495 (  to_regclass		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2205 "25" _null_ _null_ _null_ _null_ _null_ to_regclass _null_ _null_ _null_ ));
 DESCR("convert classname to regclass");
 DATA(insert OID = 2220 (  regtypein			PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2206 "2275" _null_ _null_ _null_ _null_ _null_ regtypein _null_ _null_ _null_ ));
 DESCR("I/O");
 DATA(insert OID = 2221 (  regtypeout		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2275 "2206" _null_ _null_ _null_ _null_ _null_ regtypeout _null_ _null_ _null_ ));
 DESCR("I/O");
-DATA(insert OID = 3493 (  to_regtype		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2206 "2275" _null_ _null_ _null_ _null_ _null_ to_regtype _null_ _null_ _null_ ));
+DATA(insert OID = 3493 (  to_regtype		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2206 "25" _null_ _null_ _null_ _null_ _null_ to_regtype _null_ _null_ _null_ ));
 DESCR("convert type name to regtype");
 DATA(insert OID = 1079 (  regclass			PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2205 "25" _null_ _null_ _null_ _null_ _null_	text_regclass _null_ _null_ _null_ ));
 DESCR("convert text to regclass");
@@ -3510,14 +3510,14 @@ DATA(insert OID = 4098 (  regrolein			PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0
 DESCR("I/O");
 DATA(insert OID = 4092 (  regroleout		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2275 "4096" _null_ _null_ _null_ _null_ _null_ regroleout _null_ _null_ _null_ ));
 DESCR("I/O");
-DATA(insert OID = 4093 (  to_regrole		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 4096 "2275" _null_ _null_ _null_ _null_ _null_ to_regrole _null_ _null_ _null_ ));
+DATA(insert OID = 4093 (  to_regrole		PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 4096 "25" _null_ _null_ _null_ _null_ _null_ to_regrole _null_ _null_ _null_ ));
 DESCR("convert role name to regrole");
 
 DATA(insert OID = 4084 (  regnamespacein	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 4089 "2275" _null_ _null_ _null_ _null_ _null_ regnamespacein _null_ _null_ _null_ ));
 DESCR("I/O");
 DATA(insert OID = 4085 (  regnamespaceout	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2275 "4089" _null_ _null_ _null_ _null_ _null_ regnamespaceout _null_ _null_ _null_ ));
 DESCR("I/O");
-DATA(insert OID = 4086 (  to_regnamespace	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 4089 "2275" _null_ _null_ _null_ _null_ _null_ to_regnamespace _null_ _null_ _null_ ));
+DATA(insert OID = 4086 (  to_regnamespace	PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 4089 "25" _null_ _null_ _null_ _null_ _null_ to_regnamespace _null_ _null_ _null_ ));
 DESCR("convert namespace name to regnamespace");
 
 DATA(insert OID = 2246 ( fmgr_internal_validator PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2278 "26" _null_ _null_ _null_ _null_ _null_ fmgr_internal_validator _null_ _null_ _null_ ));