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Get rid of "lookahead" functionality in plpgsql's yylex() function,
and instead make the grammar production for the RETURN statement do the heavy lifting. The lookahead idea was copied from the main parser, but it does not work in plpgsql's parser because here gram.y looks explicitly at the scanner's yytext variable, which will be out of sync after a failed lookahead step. A minimal example is create or replace function foo() returns void language plpgsql as ' begin perform return foo bar; end'; which can be seen by testing to deliver "foo foo bar" to the main parser instead of the expected "return foo bar". This isn't a huge bug since RETURN is not found in the main grammar, but it could bite someone who tried to use "return" as an identifier. Back-patch to 8.1. Bug exists further back, but HEAD patch doesn't apply cleanly, and given the lack of field complaints it doesn't seem worth the effort to develop adjusted patches.
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2 files changed

+142
-158
lines changed

2 files changed

+142
-158
lines changed

‎src/pl/plpgsql/src/gram.y‎

Lines changed: 134 additions & 119 deletions
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@
99
*
1010
*
1111
* IDENTIFICATION
12-
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.93 2006/06/16 23:29:26 tgl Exp $
12+
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.94 2006/08/14 00:46:53 tgl Exp $
1313
*
1414
*-------------------------------------------------------------------------
1515
*/
@@ -28,8 +28,10 @@ static PLpgSQL_expr *read_sql_construct(int until,
2828
int *endtoken);
2929
static PLpgSQL_expr *read_sql_stmt(const char *sqlstart);
3030
static PLpgSQL_type *read_datatype(int tok);
31-
static PLpgSQL_stmt *make_select_stmt(void);
32-
static PLpgSQL_stmt *make_fetch_stmt(void);
31+
static PLpgSQL_stmt *make_select_stmt(int lineno);
32+
static PLpgSQL_stmt *make_fetch_stmt(int lineno, int curvar);
33+
static PLpgSQL_stmt *make_return_stmt(int lineno);
34+
static PLpgSQL_stmt *make_return_next_stmt(int lineno);
3335
static void check_assignable(PLpgSQL_datum *datum);
3436
static PLpgSQL_row *read_into_scalar_list(const char *initial_name,
3537
PLpgSQL_datum *initial_datum);
@@ -118,7 +120,7 @@ static void check_labels(const char *start_label,
118120
%type <loop_body> loop_body
119121
%type <stmt> proc_stmt pl_block
120122
%type <stmt> stmt_assign stmt_if stmt_loop stmt_while stmt_exit
121-
%type <stmt> stmt_return stmt_return_next stmt_raise stmt_execsql
123+
%type <stmt> stmt_return stmt_raise stmt_execsql
122124
%type <stmt> stmt_for stmt_select stmt_perform
123125
%type <stmt> stmt_dynexecute stmt_getdiag
124126
%type <stmt> stmt_open stmt_fetch stmt_close stmt_null
@@ -183,7 +185,6 @@ static void check_labels(const char *start_label,
183185
%token K_RENAME
184186
%token K_RESULT_OID
185187
%token K_RETURN
186-
%token K_RETURN_NEXT
187188
%token K_REVERSE
188189
%token K_SELECT
189190
%token K_STRICT
@@ -596,8 +597,6 @@ proc_stmt : pl_block ';'
596597
{ $$ = $1; }
597598
| stmt_return
598599
{ $$ = $1; }
599-
| stmt_return_next
600-
{ $$ = $1; }
601600
| stmt_raise
602601
{ $$ = $1; }
603602
| stmt_execsql
@@ -1130,8 +1129,7 @@ for_variable : T_SCALAR
11301129

11311130
stmt_select : K_SELECT lno
11321131
{
1133-
$$ = make_select_stmt();
1134-
$$->lineno = $2;
1132+
$$ = make_select_stmt($2);
11351133
}
11361134
;
11371135

@@ -1162,109 +1160,18 @@ exit_type : K_EXIT
11621160

11631161
stmt_return : K_RETURN lno
11641162
{
1165-
PLpgSQL_stmt_return *new;
1166-
1167-
new = palloc0(sizeof(PLpgSQL_stmt_return));
1168-
new->cmd_type = PLPGSQL_STMT_RETURN;
1169-
new->lineno = $2;
1170-
new->expr = NULL;
1171-
new->retvarno = -1;
1163+
int tok;
11721164

1173-
if (plpgsql_curr_compile->fn_retset)
1174-
{
1175-
if (yylex() != ';')
1176-
yyerror("RETURN cannot have a parameter in function returning set; use RETURN NEXT");
1177-
}
1178-
else if (plpgsql_curr_compile->out_param_varno >= 0)
1179-
{
1180-
if (yylex() != ';')
1181-
yyerror("RETURN cannot have a parameter in function with OUT parameters");
1182-
new->retvarno = plpgsql_curr_compile->out_param_varno;
1183-
}
1184-
else if (plpgsql_curr_compile->fn_rettype == VOIDOID)
1165+
tok = yylex();
1166+
if (tok == K_NEXT)
11851167
{
1186-
if (yylex() != ';')
1187-
yyerror("RETURN cannot have a parameter in function returning void");
1188-
}
1189-
else if (plpgsql_curr_compile->fn_retistuple)
1190-
{
1191-
switch (yylex())
1192-
{
1193-
case K_NULL:
1194-
/* we allow this to support RETURN NULL in triggers */
1195-
break;
1196-
1197-
case T_ROW:
1198-
new->retvarno = yylval.row->rowno;
1199-
break;
1200-
1201-
case T_RECORD:
1202-
new->retvarno = yylval.rec->recno;
1203-
break;
1204-
1205-
default:
1206-
yyerror("RETURN must specify a record or row variable in function returning tuple");
1207-
break;
1208-
}
1209-
if (yylex() != ';')
1210-
yyerror("RETURN must specify a record or row variable in function returning tuple");
1168+
$$ = make_return_next_stmt($2);
12111169
}
12121170
else
12131171
{
1214-
/*
1215-
* Note that a well-formed expression is
1216-
* _required_ here; anything else is a
1217-
* compile-time error.
1218-
*/
1219-
new->expr = plpgsql_read_expression(';', ";");
1172+
plpgsql_push_back_token(tok);
1173+
$$ = make_return_stmt($2);
12201174
}
1221-
1222-
$$ = (PLpgSQL_stmt *)new;
1223-
}
1224-
;
1225-
1226-
stmt_return_next: K_RETURN_NEXT lno
1227-
{
1228-
PLpgSQL_stmt_return_next *new;
1229-
1230-
if (!plpgsql_curr_compile->fn_retset)
1231-
yyerror("cannot use RETURN NEXT in a non-SETOF function");
1232-
1233-
new = palloc0(sizeof(PLpgSQL_stmt_return_next));
1234-
new->cmd_type = PLPGSQL_STMT_RETURN_NEXT;
1235-
new->lineno = $2;
1236-
new->expr = NULL;
1237-
new->retvarno = -1;
1238-
1239-
if (plpgsql_curr_compile->out_param_varno >= 0)
1240-
{
1241-
if (yylex() != ';')
1242-
yyerror("RETURN NEXT cannot have a parameter in function with OUT parameters");
1243-
new->retvarno = plpgsql_curr_compile->out_param_varno;
1244-
}
1245-
else if (plpgsql_curr_compile->fn_retistuple)
1246-
{
1247-
switch (yylex())
1248-
{
1249-
case T_ROW:
1250-
new->retvarno = yylval.row->rowno;
1251-
break;
1252-
1253-
case T_RECORD:
1254-
new->retvarno = yylval.rec->recno;
1255-
break;
1256-
1257-
default:
1258-
yyerror("RETURN NEXT must specify a record or row variable in function returning tuple");
1259-
break;
1260-
}
1261-
if (yylex() != ';')
1262-
yyerror("RETURN NEXT must specify a record or row variable in function returning tuple");
1263-
}
1264-
else
1265-
new->expr = plpgsql_read_expression(';', ";");
1266-
1267-
$$ = (PLpgSQL_stmt *)new;
12681175
}
12691176
;
12701177

@@ -1537,13 +1444,7 @@ stmt_open : K_OPEN lno cursor_varptr
15371444

15381445
stmt_fetch : K_FETCH lno cursor_variable K_INTO
15391446
{
1540-
PLpgSQL_stmt_fetch *new;
1541-
1542-
new = (PLpgSQL_stmt_fetch *)make_fetch_stmt();
1543-
new->curvar = $3;
1544-
1545-
$$ = (PLpgSQL_stmt *)new;
1546-
$$->lineno = $2;
1447+
$$ = make_fetch_stmt($2, $3);
15471448
}
15481449
;
15491450

@@ -1991,7 +1892,7 @@ read_datatype(int tok)
19911892
}
19921893

19931894
static PLpgSQL_stmt *
1994-
make_select_stmt(void)
1895+
make_select_stmt(int lineno)
19951896
{
19961897
PLpgSQL_dstring ds;
19971898
int nparams = 0;
@@ -2112,6 +2013,7 @@ make_select_stmt(void)
21122013

21132014
select = palloc0(sizeof(PLpgSQL_stmt_select));
21142015
select->cmd_type = PLPGSQL_STMT_SELECT;
2016+
select->lineno = lineno;
21152017
select->rec = rec;
21162018
select->row = row;
21172019
select->query = expr;
@@ -2125,6 +2027,7 @@ make_select_stmt(void)
21252027

21262028
execsql = palloc(sizeof(PLpgSQL_stmt_execsql));
21272029
execsql->cmd_type = PLPGSQL_STMT_EXECSQL;
2030+
execsql->lineno = lineno;
21282031
execsql->sqlstmt = expr;
21292032

21302033
return (PLpgSQL_stmt *)execsql;
@@ -2133,7 +2036,7 @@ make_select_stmt(void)
21332036

21342037

21352038
static PLpgSQL_stmt *
2136-
make_fetch_stmt(void)
2039+
make_fetch_stmt(int lineno, int curvar)
21372040
{
21382041
int tok;
21392042
PLpgSQL_row *row = NULL;
@@ -2172,12 +2075,124 @@ make_fetch_stmt(void)
21722075
if (tok != ';')
21732076
yyerror("syntax error");
21742077

2175-
fetch = palloc0(sizeof(PLpgSQL_stmt_select));
2078+
fetch = palloc0(sizeof(PLpgSQL_stmt_fetch));
21762079
fetch->cmd_type = PLPGSQL_STMT_FETCH;
2177-
fetch->rec = rec;
2178-
fetch->row = row;
2080+
fetch->lineno = lineno;
2081+
fetch->rec = rec;
2082+
fetch->row = row;
2083+
fetch->curvar = curvar;
2084+
2085+
return (PLpgSQL_stmt *) fetch;
2086+
}
2087+
2088+
2089+
static PLpgSQL_stmt *
2090+
make_return_stmt(int lineno)
2091+
{
2092+
PLpgSQL_stmt_return *new;
2093+
2094+
new = palloc0(sizeof(PLpgSQL_stmt_return));
2095+
new->cmd_type = PLPGSQL_STMT_RETURN;
2096+
new->lineno = lineno;
2097+
new->expr = NULL;
2098+
new->retvarno = -1;
2099+
2100+
if (plpgsql_curr_compile->fn_retset)
2101+
{
2102+
if (yylex() != ';')
2103+
yyerror("RETURN cannot have a parameter in function returning set; use RETURN NEXT");
2104+
}
2105+
else if (plpgsql_curr_compile->out_param_varno >= 0)
2106+
{
2107+
if (yylex() != ';')
2108+
yyerror("RETURN cannot have a parameter in function with OUT parameters");
2109+
new->retvarno = plpgsql_curr_compile->out_param_varno;
2110+
}
2111+
else if (plpgsql_curr_compile->fn_rettype == VOIDOID)
2112+
{
2113+
if (yylex() != ';')
2114+
yyerror("RETURN cannot have a parameter in function returning void");
2115+
}
2116+
else if (plpgsql_curr_compile->fn_retistuple)
2117+
{
2118+
switch (yylex())
2119+
{
2120+
case K_NULL:
2121+
/* we allow this to support RETURN NULL in triggers */
2122+
break;
2123+
2124+
case T_ROW:
2125+
new->retvarno = yylval.row->rowno;
2126+
break;
2127+
2128+
case T_RECORD:
2129+
new->retvarno = yylval.rec->recno;
2130+
break;
2131+
2132+
default:
2133+
yyerror("RETURN must specify a record or row variable in function returning tuple");
2134+
break;
2135+
}
2136+
if (yylex() != ';')
2137+
yyerror("RETURN must specify a record or row variable in function returning tuple");
2138+
}
2139+
else
2140+
{
2141+
/*
2142+
* Note that a well-formed expression is
2143+
* _required_ here; anything else is a
2144+
* compile-time error.
2145+
*/
2146+
new->expr = plpgsql_read_expression(';', ";");
2147+
}
2148+
2149+
return (PLpgSQL_stmt *) new;
2150+
}
2151+
2152+
2153+
static PLpgSQL_stmt *
2154+
make_return_next_stmt(int lineno)
2155+
{
2156+
PLpgSQL_stmt_return_next *new;
2157+
2158+
if (!plpgsql_curr_compile->fn_retset)
2159+
yyerror("cannot use RETURN NEXT in a non-SETOF function");
2160+
2161+
new = palloc0(sizeof(PLpgSQL_stmt_return_next));
2162+
new->cmd_type = PLPGSQL_STMT_RETURN_NEXT;
2163+
new->lineno = lineno;
2164+
new->expr = NULL;
2165+
new->retvarno = -1;
2166+
2167+
if (plpgsql_curr_compile->out_param_varno >= 0)
2168+
{
2169+
if (yylex() != ';')
2170+
yyerror("RETURN NEXT cannot have a parameter in function with OUT parameters");
2171+
new->retvarno = plpgsql_curr_compile->out_param_varno;
2172+
}
2173+
else if (plpgsql_curr_compile->fn_retistuple)
2174+
{
2175+
switch (yylex())
2176+
{
2177+
case T_ROW:
2178+
new->retvarno = yylval.row->rowno;
2179+
break;
2180+
2181+
case T_RECORD:
2182+
new->retvarno = yylval.rec->recno;
2183+
break;
2184+
2185+
default:
2186+
yyerror("RETURN NEXT must specify a record or row variable in function returning tuple");
2187+
break;
2188+
}
2189+
if (yylex() != ';')
2190+
yyerror("RETURN NEXT must specify a record or row variable in function returning tuple");
2191+
}
2192+
else
2193+
new->expr = plpgsql_read_expression(';', ";");
21792194

2180-
return (PLpgSQL_stmt *)fetch;
2195+
return (PLpgSQL_stmt *) new;
21812196
}
21822197

21832198

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