Add a way to get the current function's OID in pl/pgsql.

Invent "GET DIAGNOSTICS oid_variable = PG_ROUTINE_OID".
This is useful for avoiding the maintenance nuisances that come
with embedding a function's name in its body, as one might do
for logging purposes for example.  Typically users would cast the
result to regproc or regprocedure to get something human-readable,
but we won't pre-judge whether that's appropriate.

Pavel Stehule, reviewed by Kirk Wolak and myself

Discussion: https://postgr.es/m/CAFj8pRA4zMd5pY-B89Gm64bDLRt-L+akOd34aD1j4PEstHHSVQ@mail.gmail.com

5 files changed, 16 insertions, 0 deletions

diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index b0a2cac227..e271ae5151 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -2411,6 +2411,12 @@ exec_stmt_getdiag(PLpgSQL_execstate *estate, PLpgSQL_stmt_getdiag *stmt)
 								  false, INT8OID, -1);
 				break;
 
+			case PLPGSQL_GETDIAG_ROUTINE_OID:
+				exec_assign_value(estate, var,
+								  ObjectIdGetDatum(estate->func->fn_oid),
+								  false, OIDOID, -1);
+				break;
+
 			case PLPGSQL_GETDIAG_ERROR_CONTEXT:
 				exec_assign_c_string(estate, var,
 									 estate->cur_error->context);
diff --git a/src/pl/plpgsql/src/pl_funcs.c b/src/pl/plpgsql/src/pl_funcs.c
index 5a6eadccd5..f010515fdf 100644
--- a/src/pl/plpgsql/src/pl_funcs.c
+++ b/src/pl/plpgsql/src/pl_funcs.c
@@ -303,6 +303,8 @@ plpgsql_getdiag_kindname(PLpgSQL_getdiag_kind kind)
 	{
 		case PLPGSQL_GETDIAG_ROW_COUNT:
 			return "ROW_COUNT";
+		case PLPGSQL_GETDIAG_ROUTINE_OID:
+			return "PG_ROUTINE_OID";
 		case PLPGSQL_GETDIAG_CONTEXT:
 			return "PG_CONTEXT";
 		case PLPGSQL_GETDIAG_ERROR_CONTEXT:
diff --git a/src/pl/plpgsql/src/pl_gram.y b/src/pl/plpgsql/src/pl_gram.y
index edeb72c380..6a09bfdd67 100644
--- a/src/pl/plpgsql/src/pl_gram.y
+++ b/src/pl/plpgsql/src/pl_gram.y
@@ -322,6 +322,7 @@ static	void			check_raise_parameters(PLpgSQL_stmt_raise *stmt);
 %token <keyword>	K_PG_EXCEPTION_CONTEXT
 %token <keyword>	K_PG_EXCEPTION_DETAIL
 %token <keyword>	K_PG_EXCEPTION_HINT
+%token <keyword>	K_PG_ROUTINE_OID
 %token <keyword>	K_PRINT_STRICT_PARAMS
 %token <keyword>	K_PRIOR
 %token <keyword>	K_QUERY
@@ -1008,6 +1009,7 @@ stmt_getdiag	: K_GET getdiag_area_opt K_DIAGNOSTICS getdiag_list ';'
 							{
 								/* these fields are disallowed in stacked case */
 								case PLPGSQL_GETDIAG_ROW_COUNT:
+								case PLPGSQL_GETDIAG_ROUTINE_OID:
 									if (new->is_stacked)
 										ereport(ERROR,
 												(errcode(ERRCODE_SYNTAX_ERROR),
@@ -1091,6 +1093,9 @@ getdiag_item :
 										   K_ROW_COUNT, "row_count"))
 							$$ = PLPGSQL_GETDIAG_ROW_COUNT;
 						else if (tok_is_keyword(tok, &yylval,
+												K_PG_ROUTINE_OID, "pg_routine_oid"))
+							$$ = PLPGSQL_GETDIAG_ROUTINE_OID;
+						else if (tok_is_keyword(tok, &yylval,
 												K_PG_CONTEXT, "pg_context"))
 							$$ = PLPGSQL_GETDIAG_CONTEXT;
 						else if (tok_is_keyword(tok, &yylval,
@@ -2528,6 +2533,7 @@ unreserved_keyword	:
 				| K_PG_EXCEPTION_CONTEXT
 				| K_PG_EXCEPTION_DETAIL
 				| K_PG_EXCEPTION_HINT
+				| K_PG_ROUTINE_OID
 				| K_PRINT_STRICT_PARAMS
 				| K_PRIOR
 				| K_QUERY
diff --git a/src/pl/plpgsql/src/pl_unreserved_kwlist.h b/src/pl/plpgsql/src/pl_unreserved_kwlist.h
index 466bdc7a20..3e258a6bb9 100644
--- a/src/pl/plpgsql/src/pl_unreserved_kwlist.h
+++ b/src/pl/plpgsql/src/pl_unreserved_kwlist.h
@@ -85,6 +85,7 @@ PG_KEYWORD("pg_datatype_name", K_PG_DATATYPE_NAME)
 PG_KEYWORD("pg_exception_context", K_PG_EXCEPTION_CONTEXT)
 PG_KEYWORD("pg_exception_detail", K_PG_EXCEPTION_DETAIL)
 PG_KEYWORD("pg_exception_hint", K_PG_EXCEPTION_HINT)
+PG_KEYWORD("pg_routine_oid", K_PG_ROUTINE_OID)
 PG_KEYWORD("print_strict_params", K_PRINT_STRICT_PARAMS)
 PG_KEYWORD("prior", K_PRIOR)
 PG_KEYWORD("query", K_QUERY)
diff --git a/src/pl/plpgsql/src/plpgsql.h b/src/pl/plpgsql/src/plpgsql.h
index 355c9f678d..c40471bb89 100644
--- a/src/pl/plpgsql/src/plpgsql.h
+++ b/src/pl/plpgsql/src/plpgsql.h
@@ -147,6 +147,7 @@ enum
 typedef enum PLpgSQL_getdiag_kind
 {
 	PLPGSQL_GETDIAG_ROW_COUNT,
+	PLPGSQL_GETDIAG_ROUTINE_OID,
 	PLPGSQL_GETDIAG_CONTEXT,
 	PLPGSQL_GETDIAG_ERROR_CONTEXT,
 	PLPGSQL_GETDIAG_ERROR_DETAIL,