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Add control knobs for plpgsql's variable resolution behavior, and make the

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default be "throw error on conflict", as per discussions.  The GUC variable
is plpgsql.variable_conflict, with values "error", "use_variable",
"use_column".  The behavior can also be specified per-function by inserting
one of
	#variable_conflict error
	#variable_conflict use_variable
	#variable_conflict use_column
at the start of the function body.

The 8.5 release notes will need to mention using "use_variable" to retain
backward-compatible behavior, although we should encourage people to migrate
to the much less mistake-prone "error" setting.

Update the plpgsql documentation to match this and other recent changes.
This commit is contained in:
Tom Lane
2009-11-13 22:43:42 +00:00
parent 01038d4ad7
commit 6317609986
9 changed files with 332 additions and 231 deletions
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22
src/pl/plpgsql/src/gram.y
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.135 2009/11/12 00:13:00 tgl Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.136 2009/11/13 22:43:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -256,6 +256,7 @@ static List *read_raise_options(void);
%token <keyword> K_ELSIF
%token <keyword> K_END
%token <keyword> K_ERRCODE
%token <keyword> K_ERROR
%token <keyword> K_EXCEPTION
%token <keyword> K_EXECUTE
%token <keyword> K_EXIT
@ -301,7 +302,10 @@ static List *read_raise_options(void);
%token <keyword> K_THEN
%token <keyword> K_TO
%token <keyword> K_TYPE
%token <keyword> K_USE_COLUMN
%token <keyword> K_USE_VARIABLE
%token <keyword> K_USING
%token <keyword> K_VARIABLE_CONFLICT
%token <keyword> K_WARNING
%token <keyword> K_WHEN
%token <keyword> K_WHILE
@ -322,6 +326,18 @@ comp_option : '#' K_OPTION K_DUMP
{
plpgsql_DumpExecTree = true;
}
| '#' K_VARIABLE_CONFLICT K_ERROR
{
plpgsql_curr_compile->resolve_option = PLPGSQL_RESOLVE_ERROR;
}
| '#' K_VARIABLE_CONFLICT K_USE_VARIABLE
{
plpgsql_curr_compile->resolve_option = PLPGSQL_RESOLVE_VARIABLE;
}
| '#' K_VARIABLE_CONFLICT K_USE_COLUMN
{
plpgsql_curr_compile->resolve_option = PLPGSQL_RESOLVE_COLUMN;
}
;
opt_semi :
@ -1969,6 +1985,7 @@ unreserved_keyword :
| K_DETAIL
| K_DUMP
| K_ERRCODE
| K_ERROR
| K_FIRST
| K_FORWARD
| K_HINT
@ -1991,6 +2008,9 @@ unreserved_keyword :
| K_SCROLL
| K_SQLSTATE
| K_TYPE
| K_USE_COLUMN
| K_USE_VARIABLE
| K_VARIABLE_CONFLICT
| K_WARNING
;

12
src/pl/plpgsql/src/pl_comp.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.145 2009/11/12 00:13:00 tgl Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.146 2009/11/13 22:43:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -351,7 +351,7 @@ do_compile(FunctionCallInfo fcinfo,
function->fn_is_trigger = is_trigger;
function->fn_cxt = func_cxt;
function->out_param_varno = -1; /* set up for no OUT param */
function->resolve_option = PLPGSQL_RESOLVE_BEFORE;
function->resolve_option = plpgsql_variable_conflict;
/*
* Initialize the compiler, particularly the namespace stack. The
@ -782,7 +782,7 @@ plpgsql_compile_inline(char *proc_source)
function->fn_is_trigger = false;
function->fn_cxt = func_cxt;
function->out_param_varno = -1; /* set up for no OUT param */
function->resolve_option = PLPGSQL_RESOLVE_BEFORE;
function->resolve_option = plpgsql_variable_conflict;
plpgsql_ns_init();
plpgsql_ns_push(func_name);
@ -948,7 +948,7 @@ plpgsql_pre_column_ref(ParseState *pstate, ColumnRef *cref)
{
PLpgSQL_expr *expr = (PLpgSQL_expr *) pstate->p_ref_hook_state;
if (expr->func->resolve_option == PLPGSQL_RESOLVE_BEFORE)
if (expr->func->resolve_option == PLPGSQL_RESOLVE_VARIABLE)
return resolve_column_ref(expr, cref);
else
return NULL;
@ -963,10 +963,10 @@ plpgsql_post_column_ref(ParseState *pstate, ColumnRef *cref, Node *var)
PLpgSQL_expr *expr = (PLpgSQL_expr *) pstate->p_ref_hook_state;
Node *myvar;
if (expr->func->resolve_option == PLPGSQL_RESOLVE_BEFORE)
if (expr->func->resolve_option == PLPGSQL_RESOLVE_VARIABLE)
return NULL; /* we already found there's no match */
if (expr->func->resolve_option == PLPGSQL_RESOLVE_AFTER && var != NULL)
if (expr->func->resolve_option == PLPGSQL_RESOLVE_COLUMN && var != NULL)
return NULL; /* there's a table column, prefer that */
myvar = resolve_column_ref(expr, cref);

24
src/pl/plpgsql/src/pl_handler.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_handler.c,v 1.47 2009/11/04 22:26:07 tgl Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_handler.c,v 1.48 2009/11/13 22:43:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -26,6 +26,17 @@
PG_MODULE_MAGIC;
/* Custom GUC variable */
static const struct config_enum_entry variable_conflict_options[] = {
{"error", PLPGSQL_RESOLVE_ERROR, false},
{"use_variable", PLPGSQL_RESOLVE_VARIABLE, false},
{"use_column", PLPGSQL_RESOLVE_COLUMN, false},
{NULL, 0, false}
};
int plpgsql_variable_conflict = PLPGSQL_RESOLVE_ERROR;
/* Hook for plugins */
PLpgSQL_plugin **plugin_ptr = NULL;
@ -45,6 +56,17 @@ _PG_init(void)
pg_bindtextdomain(TEXTDOMAIN);
DefineCustomEnumVariable("plpgsql.variable_conflict",
gettext_noop("Sets handling of conflicts between PL/pgSQL variable names and table column names."),
NULL,
&plpgsql_variable_conflict,
PLPGSQL_RESOLVE_ERROR,
variable_conflict_options,
PGC_SUSET, 0,
NULL, NULL);
EmitWarningsOnPlaceholders("plpgsql");
plpgsql_HashTableInit();
RegisterXactCallback(plpgsql_xact_cb, NULL);
RegisterSubXactCallback(plpgsql_subxact_cb, NULL);

6
src/pl/plpgsql/src/pl_scanner.c
View File

@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_scanner.c,v 1.1 2009/11/12 00:13:00 tgl Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_scanner.c,v 1.2 2009/11/13 22:43:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -113,6 +113,7 @@ static const ScanKeyword unreserved_keywords[] = {
PG_KEYWORD("detail", K_DETAIL, UNRESERVED_KEYWORD)
PG_KEYWORD("dump", K_DUMP, UNRESERVED_KEYWORD)
PG_KEYWORD("errcode", K_ERRCODE, UNRESERVED_KEYWORD)
PG_KEYWORD("error", K_ERROR, UNRESERVED_KEYWORD)
PG_KEYWORD("first", K_FIRST, UNRESERVED_KEYWORD)
PG_KEYWORD("forward", K_FORWARD, UNRESERVED_KEYWORD)
PG_KEYWORD("hint", K_HINT, UNRESERVED_KEYWORD)
@ -135,6 +136,9 @@ static const ScanKeyword unreserved_keywords[] = {
PG_KEYWORD("scroll", K_SCROLL, UNRESERVED_KEYWORD)
PG_KEYWORD("sqlstate", K_SQLSTATE, UNRESERVED_KEYWORD)
PG_KEYWORD("type", K_TYPE, UNRESERVED_KEYWORD)
PG_KEYWORD("use_column", K_USE_COLUMN, UNRESERVED_KEYWORD)
PG_KEYWORD("use_variable", K_USE_VARIABLE, UNRESERVED_KEYWORD)
PG_KEYWORD("variable_conflict", K_VARIABLE_CONFLICT, UNRESERVED_KEYWORD)
PG_KEYWORD("warning", K_WARNING, UNRESERVED_KEYWORD)
};

10
src/pl/plpgsql/src/plpgsql.h
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.124 2009/11/12 00:13:00 tgl Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.125 2009/11/13 22:43:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -147,9 +147,9 @@ enum
*/
typedef enum
{
PLPGSQL_RESOLVE_BEFORE, /* prefer plpgsql var to table column */
PLPGSQL_RESOLVE_AFTER, /* prefer table column to plpgsql var */
PLPGSQL_RESOLVE_ERROR /* throw error if ambiguous */
PLPGSQL_RESOLVE_ERROR, /* throw error if ambiguous */
PLPGSQL_RESOLVE_VARIABLE, /* prefer plpgsql var to table column */
PLPGSQL_RESOLVE_COLUMN /* prefer table column to plpgsql var */
} PLpgSQL_resolve_option;
@ -794,6 +794,8 @@ typedef struct
* Global variable declarations
**********************************************************************/
extern int plpgsql_variable_conflict;
extern bool plpgsql_check_syntax;
extern bool plpgsql_DumpExecTree;
extern bool plpgsql_LookupIdentifiers;

38
src/test/regress/expected/plpgsql.out
View File

@ -4004,6 +4004,7 @@ select scope_test();
drop function scope_test();
-- Check handling of conflicts between plpgsql vars and table columns.
set plpgsql.variable_conflict = error;
create function conflict_test() returns setof int8_tbl as $$
declare r record;
q1 bigint := 42;
@ -4013,6 +4014,23 @@ begin
end loop;
end;
$$ language plpgsql;
select * from conflict_test();
ERROR: column reference "q1" is ambiguous
LINE 1: select q1,q2 from int8_tbl
^
DETAIL: It could refer to either a PL/pgSQL variable or a table column.
QUERY: select q1,q2 from int8_tbl
CONTEXT: PL/pgSQL function "conflict_test" line 4 at FOR over SELECT rows
create or replace function conflict_test() returns setof int8_tbl as $$
#variable_conflict use_variable
declare r record;
q1 bigint := 42;
begin
for r in select q1,q2 from int8_tbl loop
return next r;
end loop;
end;
$$ language plpgsql;
select * from conflict_test();
q1 | q2
----+-------------------
@ -4023,6 +4041,26 @@ select * from conflict_test();
42 | -4567890123456789
(5 rows)
create or replace function conflict_test() returns setof int8_tbl as $$
#variable_conflict use_column
declare r record;
q1 bigint := 42;
begin
for r in select q1,q2 from int8_tbl loop
return next r;
end loop;
end;
$$ language plpgsql;
select * from conflict_test();
q1 | q2
------------------+-------------------
123 | 456
123 | 4567890123456789
4567890123456789 | 123
4567890123456789 | 4567890123456789
4567890123456789 | -4567890123456789
(5 rows)
drop function conflict_test();
-- Check that an unreserved keyword can be used as a variable name
create function unreserved_test() returns int as $$

28
src/test/regress/sql/plpgsql.sql
View File

@ -3176,6 +3176,8 @@ drop function scope_test();
-- Check handling of conflicts between plpgsql vars and table columns.
set plpgsql.variable_conflict = error;
create function conflict_test() returns setof int8_tbl as $$
declare r record;
q1 bigint := 42;
@ -3188,6 +3190,32 @@ $$ language plpgsql;
select * from conflict_test();
create or replace function conflict_test() returns setof int8_tbl as $$
#variable_conflict use_variable
declare r record;
q1 bigint := 42;
begin
for r in select q1,q2 from int8_tbl loop
return next r;
end loop;
end;
$$ language plpgsql;
select * from conflict_test();
create or replace function conflict_test() returns setof int8_tbl as $$
#variable_conflict use_column
declare r record;
q1 bigint := 42;
begin
for r in select q1,q2 from int8_tbl loop
return next r;
end loop;
end;
$$ language plpgsql;
select * from conflict_test();
drop function conflict_test();
-- Check that an unreserved keyword can be used as a variable name