Tom Lane wrote:
A nonterminal that is not intended to represent any real input, ever,
is just plain weird.
If you say so... PL/PgSQL already uses such a beast, though: the lno
nonterminal, for example.
Not at all. The right way to do this, I think, is for the mid-rule
action to palloc the PLpgSQL_exception_block, fill the variables into
that, and return the block as its semantic value. The end-of-rule
action then picks up the block and adds what it needs to.
Ah, I see -- that makes sense. Attached is a revised patch -- applied to
HEAD.
-Neil
Index: doc/src/sgml/plpgsql.sgml
===================================================================
RCS file: /Users/neilc/local/cvs/pgsql/doc/src/sgml/plpgsql.sgml,v
retrieving revision 1.70
diff -c -r1.70 plpgsql.sgml
*** doc/src/sgml/plpgsql.sgml 7 Jun 2005 02:47:15 -0000 1.70
--- doc/src/sgml/plpgsql.sgml 10 Jun 2005 15:34:04 -0000
***************
*** 2110,2115 ****
--- 2110,2126 ----
don't use <literal>EXCEPTION</> without need.
</para>
</tip>
+
+ <para>
+ Within an exception handler, the <varname>SQLSTATE</varname>
+ variable contains the error code that corresponds to the
+ exception that was raised (refer to <xref
+ linkend="errcodes-table"> for a list of possible error
+ codes). The <varname>SQLERRM</varname> variable contains the
+ error message associated with the exception. These variables are
+ undefined outside exception handlers.
+ </para>
+
<example id="plpgsql-upsert-example">
<title>Exceptions with UPDATE/INSERT</title>
<para>
Index: src/backend/utils/error/elog.c
===================================================================
RCS file: /Users/neilc/local/cvs/pgsql/src/backend/utils/error/elog.c,v
retrieving revision 1.159
diff -c -r1.159 elog.c
*** src/backend/utils/error/elog.c 9 Jun 2005 22:29:52 -0000 1.159
--- src/backend/utils/error/elog.c 10 Jun 2005 15:34:04 -0000
***************
*** 1482,1487 ****
--- 1482,1507 ----
}
}
+ /*
+ * Unpack MAKE_SQLSTATE code. Note that this returns a pointer to a
+ * static buffer.
+ */
+ char *
+ unpack_sql_state(int sql_state)
+ {
+ static char buf[12];
+ int i;
+
+ for (i = 0; i < 5; i++)
+ {
+ buf[i] = PGUNSIXBIT(sql_state);
+ sql_state >>= 6;
+ }
+
+ buf[i] = '\0';
+ return buf;
+ }
+
/*
* Write error report to server's log
***************
*** 1497,1517 ****
appendStringInfo(&buf, "%s: ", error_severity(edata->elevel));
if (Log_error_verbosity >= PGERROR_VERBOSE)
! {
! /* unpack MAKE_SQLSTATE code */
! char tbuf[12];
! int ssval;
! int i;
!
! ssval = edata->sqlerrcode;
! for (i = 0; i < 5; i++)
! {
! tbuf[i] = PGUNSIXBIT(ssval);
! ssval >>= 6;
! }
! tbuf[i] = '\0';
! appendStringInfo(&buf, "%s: ", tbuf);
! }
if (edata->message)
append_with_tabs(&buf, edata->message);
--- 1517,1523 ----
appendStringInfo(&buf, "%s: ", error_severity(edata->elevel));
if (Log_error_verbosity >= PGERROR_VERBOSE)
! appendStringInfo(&buf, "%s: ", unpack_sql_state(edata->sqlerrcode));
if (edata->message)
append_with_tabs(&buf, edata->message);
Index: src/include/utils/elog.h
===================================================================
RCS file: /Users/neilc/local/cvs/pgsql/src/include/utils/elog.h,v
retrieving revision 1.78
diff -c -r1.78 elog.h
*** src/include/utils/elog.h 31 Dec 2004 22:03:46 -0000 1.78
--- src/include/utils/elog.h 10 Jun 2005 15:34:04 -0000
***************
*** 282,287 ****
--- 282,288 ----
/* Other exported functions */
extern void DebugFileOpen(void);
+ extern char *unpack_sql_state(int sql_state);
/*
* Write errors to stderr (or by equal means when stderr is
Index: src/pl/plpgsql/src/gram.y
===================================================================
RCS file: /Users/neilc/local/cvs/pgsql/src/pl/plpgsql/src/gram.y,v
retrieving revision 1.74
diff -c -r1.74 gram.y
*** src/pl/plpgsql/src/gram.y 8 Jun 2005 00:49:36 -0000 1.74
--- src/pl/plpgsql/src/gram.y 10 Jun 2005 16:02:48 -0000
***************
*** 92,97 ****
--- 92,98 ----
PLpgSQL_stmt_block *program;
PLpgSQL_condition *condition;
PLpgSQL_exception *exception;
+ PLpgSQL_exception_block *exception_block;
PLpgSQL_nsitem *nsitem;
PLpgSQL_diag_item *diagitem;
}
***************
*** 129,135 ****
%type <stmt> stmt_dynexecute stmt_getdiag
%type <stmt> stmt_open stmt_fetch stmt_close stmt_null
! %type <list> exception_sect proc_exceptions
%type <exception> proc_exception
%type <condition> proc_conditions
--- 130,137 ----
%type <stmt> stmt_dynexecute stmt_getdiag
%type <stmt> stmt_open stmt_fetch stmt_close stmt_null
! %type <list> proc_exceptions
! %type <exception_block> exception_sect
%type <exception> proc_exception
%type <condition> proc_conditions
***************
*** 1495,1503 ****
;
exception_sect :
! { $$ = NIL; }
! | K_EXCEPTION proc_exceptions
! { $$ = $2; }
;
proc_exceptions : proc_exceptions proc_exception
--- 1497,1534 ----
;
exception_sect :
! { $$ = NULL; }
! | K_EXCEPTION lno
! {
! /*
! * We use a mid-rule action to add these
! * special variables to the namespace before
! * parsing the WHEN clauses themselves.
! */
! PLpgSQL_exception_block *new = palloc(sizeof(PLpgSQL_exception_block));
! PLpgSQL_variable *var;
!
! var = plpgsql_build_variable("sqlstate", $2,
! plpgsql_build_datatype(TEXTOID, -1),
! true);
! ((PLpgSQL_var *) var)->isconst = true;
! new->sqlstate_varno = var->dno;
!
! var = plpgsql_build_variable("sqlerrm", $2,
! plpgsql_build_datatype(TEXTOID, -1),
! true);
! ((PLpgSQL_var *) var)->isconst = true;
! new->sqlerrm_varno = var->dno;
!
! $<exception_block>$ = new;
! }
! proc_exceptions
! {
! PLpgSQL_exception_block *new = $<exception_block>3;
! new->exc_list = $4;
!
! $$ = new;
! }
;
proc_exceptions : proc_exceptions proc_exception
Index: src/pl/plpgsql/src/pl_comp.c
===================================================================
RCS file: /Users/neilc/local/cvs/pgsql/src/pl/plpgsql/src/pl_comp.c,v
retrieving revision 1.90
diff -c -r1.90 pl_comp.c
*** src/pl/plpgsql/src/pl_comp.c 29 May 2005 04:23:06 -0000 1.90
--- src/pl/plpgsql/src/pl_comp.c 10 Jun 2005 15:34:04 -0000
***************
*** 656,662 ****
if (num_out_args > 0 || function->fn_rettype == VOIDOID ||
function->fn_retset)
{
! if (function->action->exceptions != NIL)
{
PLpgSQL_stmt_block *new;
--- 656,662 ----
if (num_out_args > 0 || function->fn_rettype == VOIDOID ||
function->fn_retset)
{
! if (function->action->exceptions != NULL)
{
PLpgSQL_stmt_block *new;
***************
*** 882,888 ****
}
/*
! * Do a lookup on the compilers namestack
*/
nse = plpgsql_ns_lookup(cp[0], NULL);
if (nse != NULL)
--- 882,888 ----
}
/*
! * Do a lookup on the compiler's namestack
*/
nse = plpgsql_ns_lookup(cp[0], NULL);
if (nse != NULL)
***************
*** 1935,1941 ****
/* ----------
* plpgsql_adddatum Add a variable, record or row
! * to the compilers datum list.
* ----------
*/
void
--- 1935,1941 ----
/* ----------
* plpgsql_adddatum Add a variable, record or row
! * to the compiler's datum list.
* ----------
*/
void
Index: src/pl/plpgsql/src/pl_exec.c
===================================================================
RCS file: /Users/neilc/local/cvs/pgsql/src/pl/plpgsql/src/pl_exec.c,v
retrieving revision 1.142
diff -c -r1.142 pl_exec.c
*** src/pl/plpgsql/src/pl_exec.c 7 Jun 2005 02:47:17 -0000 1.142
--- src/pl/plpgsql/src/pl_exec.c 10 Jun 2005 15:34:04 -0000
***************
*** 180,186 ****
static void exec_init_tuple_store(PLpgSQL_execstate *estate);
static bool compatible_tupdesc(TupleDesc td1, TupleDesc td2);
static void exec_set_found(PLpgSQL_execstate *estate, bool state);
!
/* ----------
* plpgsql_exec_function Called by the call handler for
--- 180,186 ----
static void exec_init_tuple_store(PLpgSQL_execstate *estate);
static bool compatible_tupdesc(TupleDesc td1, TupleDesc td2);
static void exec_set_found(PLpgSQL_execstate *estate, bool state);
! static void free_var(PLpgSQL_var *var);
/* ----------
* plpgsql_exec_function Called by the call handler for
***************
*** 760,771 ****
{
PLpgSQL_var *var = (PLpgSQL_var *) (estate->datums[n]);
! if (var->freeval)
! {
! pfree((void *) (var->value));
! var->freeval = false;
! }
!
if (!var->isconst || var->isnull)
{
if (var->default_val == NULL)
--- 760,766 ----
{
PLpgSQL_var *var = (PLpgSQL_var *) (estate->datums[n]);
! free_var(var);
if (!var->isconst || var->isnull)
{
if (var->default_val == NULL)
***************
*** 864,876 ****
SPI_restore_connection();
/* Look for a matching exception handler */
! foreach (e, block->exceptions)
{
PLpgSQL_exception *exception = (PLpgSQL_exception *) lfirst(e);
if (exception_matches_conditions(edata, exception->conditions))
{
rc = exec_stmts(estate, exception->action);
break;
}
}
--- 859,895 ----
SPI_restore_connection();
/* Look for a matching exception handler */
! foreach (e, block->exceptions->exc_list)
{
PLpgSQL_exception *exception = (PLpgSQL_exception *) lfirst(e);
if (exception_matches_conditions(edata, exception->conditions))
{
+ /*
+ * Initialize the magic SQLSTATE and SQLERRM
+ * variables for the exception block. We needn't
+ * do this until we have found a matching
+ * exception.
+ */
+ PLpgSQL_var *state_var;
+ PLpgSQL_var *errm_var;
+
+ state_var = (PLpgSQL_var *) (estate->datums[block->exceptions->sqlstate_varno]);
+ state_var->value = DirectFunctionCall1(textin,
+ CStringGetDatum(unpack_sql_state(edata->sqlerrcode)));
+ state_var->freeval = true;
+ state_var->isnull = false;
+
+ errm_var = (PLpgSQL_var *) (estate->datums[block->exceptions->sqlerrm_varno]);
+ errm_var->value = DirectFunctionCall1(textin,
+ CStringGetDatum(edata->message));
+ errm_var->freeval = true;
+ errm_var->isnull = false;
+
rc = exec_stmts(estate, exception->action);
+
+ free_var(state_var);
+ free_var(errm_var);
break;
}
}
***************
*** 2586,2594 ****
* Store the eventually assigned cursor name in the cursor variable
* ----------
*/
! if (curvar->freeval)
! pfree((void *) (curvar->value));
!
curvar->value = DirectFunctionCall1(textin, CStringGetDatum(portal->name));
curvar->isnull = false;
curvar->freeval = true;
--- 2605,2611 ----
* Store the eventually assigned cursor name in the cursor variable
* ----------
*/
! free_var(curvar);
curvar->value = DirectFunctionCall1(textin, CStringGetDatum(portal->name));
curvar->isnull = false;
curvar->freeval = true;
***************
*** 2684,2692 ****
* Store the eventually assigned portal name in the cursor variable
* ----------
*/
! if (curvar->freeval)
! pfree((void *) (curvar->value));
!
curvar->value = DirectFunctionCall1(textin, CStringGetDatum(portal->name));
curvar->isnull = false;
curvar->freeval = true;
--- 2701,2707 ----
* Store the eventually assigned portal name in the cursor variable
* ----------
*/
! free_var(curvar);
curvar->value = DirectFunctionCall1(textin, CStringGetDatum(portal->name));
curvar->isnull = false;
curvar->freeval = true;
***************
*** 2857,2867 ****
errmsg("NULL cannot be assigned to variable \"%s\" declared NOT NULL",
var->refname)));
! if (var->freeval)
! {
! pfree(DatumGetPointer(var->value));
! var->freeval = false;
! }
/*
* If type is by-reference, make sure we have a freshly
--- 2872,2878 ----
errmsg("NULL cannot be assigned to variable \"%s\" declared NOT NULL",
var->refname)));
! free_var(var);
/*
* If type is by-reference, make sure we have a freshly
***************
*** 4343,4345 ****
--- 4354,4366 ----
FreeExecutorState(simple_eval_estate);
simple_eval_estate = NULL;
}
+
+ static void
+ free_var(PLpgSQL_var *var)
+ {
+ if (var->freeval)
+ {
+ pfree(DatumGetPointer(var->value));
+ var->freeval = false;
+ }
+ }
Index: src/pl/plpgsql/src/pl_funcs.c
===================================================================
RCS file: /Users/neilc/local/cvs/pgsql/src/pl/plpgsql/src/pl_funcs.c,v
retrieving revision 1.40
diff -c -r1.40 pl_funcs.c
*** src/pl/plpgsql/src/pl_funcs.c 5 Apr 2005 06:22:16 -0000 1.40
--- src/pl/plpgsql/src/pl_funcs.c 10 Jun 2005 15:34:04 -0000
***************
*** 634,640 ****
{
ListCell *e;
! foreach (e, block->exceptions)
{
PLpgSQL_exception *exc = (PLpgSQL_exception *) lfirst(e);
PLpgSQL_condition *cond;
--- 634,640 ----
{
ListCell *e;
! foreach (e, block->exceptions->exc_list)
{
PLpgSQL_exception *exc = (PLpgSQL_exception *) lfirst(e);
PLpgSQL_condition *cond;
Index: src/pl/plpgsql/src/plpgsql.h
===================================================================
RCS file: /Users/neilc/local/cvs/pgsql/src/pl/plpgsql/src/plpgsql.h,v
retrieving revision 1.61
diff -c -r1.61 plpgsql.h
*** src/pl/plpgsql/src/plpgsql.h 7 Jun 2005 02:47:18 -0000 1.61
--- src/pl/plpgsql/src/plpgsql.h 10 Jun 2005 15:34:04 -0000
***************
*** 323,328 ****
--- 323,335 ----
} PLpgSQL_condition;
typedef struct
+ {
+ int sqlstate_varno;
+ int sqlerrm_varno;
+ List *exc_list; /* List of WHEN clauses */
+ } PLpgSQL_exception_block;
+
+ typedef struct
{ /* One EXCEPTION ... WHEN clause */
int lineno;
PLpgSQL_condition *conditions;
***************
*** 336,344 ****
int lineno;
char *label;
List *body; /* List of statements */
- List *exceptions; /* List of WHEN clauses */
int n_initvars;
int *initvarnos;
} PLpgSQL_stmt_block;
--- 343,351 ----
int lineno;
char *label;
List *body; /* List of statements */
int n_initvars;
int *initvarnos;
+ PLpgSQL_exception_block *exceptions;
} PLpgSQL_stmt_block;
Index: src/test/regress/expected/plpgsql.out
===================================================================
RCS file: /Users/neilc/local/cvs/pgsql/src/test/regress/expected/plpgsql.out,v
retrieving revision 1.32
diff -c -r1.32 plpgsql.out
*** src/test/regress/expected/plpgsql.out 7 Jun 2005 02:47:20 -0000 1.32
--- src/test/regress/expected/plpgsql.out 10 Jun 2005 15:34:04 -0000
***************
*** 2415,2417 ****
--- 2415,2471 ----
drop table eifoo cascade;
drop type eitype cascade;
+ --
+ -- SQLSTATE and SQLERRM test
+ --
+ -- should fail: SQLSTATE and SQLERRM are only in defined EXCEPTION
+ -- blocks
+ create function excpt_test() returns void as $$
+ begin
+ raise notice '% %', sqlstate, sqlerrm;
+ end; $$ language plpgsql;
+ ERROR: syntax error at or near "sqlstate" at character 79
+ LINE 3: raise notice '% %', sqlstate, sqlerrm;
+ ^
+ -- should fail
+ create function excpt_test() returns void as $$
+ begin
+ begin
+ begin
+ raise notice '% %', sqlstate, sqlerrm;
+ end;
+ end;
+ end; $$ language plpgsql;
+ ERROR: syntax error at or near "sqlstate" at character 108
+ LINE 5: raise notice '% %', sqlstate, sqlerrm;
+ ^
+ create function excpt_test() returns void as $$
+ begin
+ begin
+ raise exception 'user exception';
+ exception when others then
+ raise notice 'caught exception % %', sqlstate, sqlerrm;
+ begin
+ raise notice '% %', sqlstate, sqlerrm;
+ perform 10/0;
+ exception
+ when substring_error then
+ -- this exception handler shouldn't be invoked
+ raise notice 'unexpected exception: % %', sqlstate, sqlerrm;
+ when division_by_zero then
+ raise notice 'caught exception % %', sqlstate, sqlerrm;
+ end;
+ raise notice '% %', sqlstate, sqlerrm;
+ end;
+ end; $$ language plpgsql;
+ select excpt_test();
+ NOTICE: caught exception P0001 user exception
+ NOTICE: P0001 user exception
+ NOTICE: caught exception 22012 division by zero
+ NOTICE: P0001 user exception
+ excpt_test
+ ------------
+
+ (1 row)
+
+ drop function excpt_test();
Index: src/test/regress/sql/plpgsql.sql
===================================================================
RCS file: /Users/neilc/local/cvs/pgsql/src/test/regress/sql/plpgsql.sql,v
retrieving revision 1.27
diff -c -r1.27 plpgsql.sql
*** src/test/regress/sql/plpgsql.sql 7 Jun 2005 02:47:23 -0000 1.27
--- src/test/regress/sql/plpgsql.sql 10 Jun 2005 15:34:04 -0000
***************
*** 2050,2052 ****
--- 2050,2096 ----
drop table eifoo cascade;
drop type eitype cascade;
+
+ --
+ -- SQLSTATE and SQLERRM test
+ --
+
+ -- should fail: SQLSTATE and SQLERRM are only in defined EXCEPTION
+ -- blocks
+ create function excpt_test() returns void as $$
+ begin
+ raise notice '% %', sqlstate, sqlerrm;
+ end; $$ language plpgsql;
+
+ -- should fail
+ create function excpt_test() returns void as $$
+ begin
+ begin
+ begin
+ raise notice '% %', sqlstate, sqlerrm;
+ end;
+ end;
+ end; $$ language plpgsql;
+
+ create function excpt_test() returns void as $$
+ begin
+ begin
+ raise exception 'user exception';
+ exception when others then
+ raise notice 'caught exception % %', sqlstate, sqlerrm;
+ begin
+ raise notice '% %', sqlstate, sqlerrm;
+ perform 10/0;
+ exception
+ when substring_error then
+ -- this exception handler shouldn't be invoked
+ raise notice 'unexpected exception: % %', sqlstate, sqlerrm;
+ when division_by_zero then
+ raise notice 'caught exception % %', sqlstate, sqlerrm;
+ end;
+ raise notice '% %', sqlstate, sqlerrm;
+ end;
+ end; $$ language plpgsql;
+
+ select excpt_test();
+ drop function excpt_test();
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