Make the file_fdw validator check that a filename option has been provided.

This was already a runtime failure condition, but it's better to check
at validation time if possible.  Lightly modified version of a patch
by Shigeru Hanada.

contrib/file_fdw/file_fdw.c

@@ -215,6 +215,14 @@ file_fdw_validator(PG_FUNCTION_ARGS)
 	 */
 	ProcessCopyOptions(NULL, true, other_options);
 
+	/*
+	 * Filename option is required for file_fdw foreign tables.
+	 */
+	if (catalog == ForeignTableRelationId && filename == NULL)
+		ereport(ERROR,
+				(errcode(ERRCODE_FDW_DYNAMIC_PARAMETER_VALUE_NEEDED),
+				 errmsg("filename is required for file_fdw foreign tables")));
+
 	PG_RETURN_VOID();
 }
 
@@ -286,10 +294,14 @@ fileGetOptions(Oid foreigntableid,
 		}
 		prev = lc;
 	}
+
+	/*
+	 * The validator should have checked that a filename was included in the
+	 * options, but check again, just in case.
+	 */
 	if (*filename == NULL)
-		ereport(ERROR,
-				(errcode(ERRCODE_FDW_UNABLE_TO_CREATE_REPLY),
-				 errmsg("filename is required for file_fdw foreign tables")));
+		elog(ERROR, "filename is required for file_fdw foreign tables");
+
 	*other_options = options;
 }
 

contrib/file_fdw/input/file_fdw.source

@@ -59,6 +59,7 @@ CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'csv', delimiter
 ');       -- ERROR
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'csv', null '
 ');       -- ERROR
+CREATE FOREIGN TABLE tbl () SERVER file_server;  -- ERROR
 
 CREATE FOREIGN TABLE agg_text (
 	a	int2,

contrib/file_fdw/output/file_fdw.source

@@ -75,6 +75,8 @@ ERROR:  COPY delimiter cannot be newline or carriage return
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'csv', null '
 ');       -- ERROR
 ERROR:  COPY null representation cannot use newline or carriage return
+CREATE FOREIGN TABLE tbl () SERVER file_server;  -- ERROR
+ERROR:  filename is required for file_fdw foreign tables
 CREATE FOREIGN TABLE agg_text (
 	a	int2,
 	b	float4