!76 增加varchar 长度 校验

Merge pull request !76 from nifinity/master

src/common/backend/catalog/system_views.sql

@@ -1656,8 +1656,8 @@ AS $$ SELECT CAST(float8out($1) AS VARCHAR2) $$
 LANGUAGE SQL  STRICT IMMUTABLE NOT FENCED;
 
 CREATE OR REPLACE FUNCTION to_char(TEXT)
-RETURNS TEXT
-AS $$ SELECT $1 $$
+RETURNS varchar
+AS $$ SELECT $1::varchar(10485760) $$
 LANGUAGE SQL  STRICT IMMUTABLE NOT FENCED;
 
 CREATE OR REPLACE FUNCTION to_number(TEXT)

src/common/backend/utils/adt/varchar.cpp

@@ -572,6 +572,12 @@ Datum varchar(PG_FUNCTION_ARGS)
 
     /* only reach here if string is too long... */
 
+    if (len > MaxAttrSize) {
+        ereport(ERROR,
+            (errcode(ERRCODE_STRING_DATA_RIGHT_TRUNCATION),
+                errmsg("value too long for type character varying maxlen(%d) input_len(%d)", MaxAttrSize, len)));
+    }
+
     /* truncate multibyte string preserving multibyte boundary */
     max_mb_len = pg_mbcharcliplen(s_data, len, max_len);
 

src/test/regress/expected/varchar.out

@@ -108,3 +108,14 @@ SELECT '' AS four, * FROM VARCHAR_TBL ORDER BY f1;
       | abcd
 (4 rows)
 
+select char_length(to_char(lpad('abc', 1024 * 1024 *10, 'x')));
+ char_length 
+-------------
+    10485760
+(1 row)
+
+select char_length(to_char(lpad('abc', 1024 * 1024 *10 + 1, 'x')));
+ERROR:  value too long for type character varying maxlen(10485760) input_len(10485761)
+CONTEXT:  referenced column: varchar
+SQL function "to_char" statement 1
+referenced column: char_length

src/test/regress/sql/varchar.sql

@@ -64,3 +64,7 @@ INSERT INTO VARCHAR_TBL (f1) VALUES ('abcde');
 INSERT INTO VARCHAR_TBL (f1) VALUES ('abcd    ');
 
 SELECT '' AS four, * FROM VARCHAR_TBL ORDER BY f1;
+
+select char_length(to_char(lpad('abc', 1024 * 1024 *10, 'x')));
+
+select char_length(to_char(lpad('abc', 1024 * 1024 *10 + 1, 'x')));