Instead of trying (and failing) to allow <<label>> at the end of a DECLARE

section, throw an error message saying explicitly that the label must go
before DECLARE.  Per investigation of a recent pgsql-novice question,
this code did not work as intended in any modern PG version, maybe not ever.
Allowing such a thing would only create ambiguity anyway, so it seems better
to remove it than fix it.

diff --git a/src/pl/plpgsql/src/gram.y b/src/pl/plpgsql/src/gram.y
index fbe1786..e866d10 100644 (file)
--- a/src/pl/plpgsql/src/gram.y
+++ b/src/pl/plpgsql/src/gram.y
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.141 2010/03/02 16:14:39 tgl Exp $
+ *       $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.142 2010/03/03 01:53:17 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -170,7 +170,6 @@ static      List                    *read_raise_options(void);
 %type <datum>  decl_cursor_args
 %type <list>   decl_cursor_arglist
 %type <nsitem> decl_aliasitem
-%type <str>            decl_stmts decl_stmt
 
 %type <expr>   expr_until_semi expr_until_rightbracket
 %type <expr>   expr_until_then expr_until_loop opt_expr_until_when
@@ -386,10 +385,7 @@ decl_sect          : opt_block_label
                                | opt_block_label decl_start decl_stmts
                                        {
                                                plpgsql_IdentifierLookup = IDENTIFIER_LOOKUP_NORMAL;
-                                               if ($3 != NULL)
-                                                       $$.label = $3;
-                                               else
-                                                       $$.label = $1;
+                                               $$.label          = $1;
                                                /* Remember variables declared in decl_stmts */
                                                $$.n_initvars = plpgsql_add_initdatums(&($$.initvarnos));
                                        }
@@ -408,17 +404,25 @@ decl_start                : K_DECLARE
                                ;
 
 decl_stmts             : decl_stmts decl_stmt
-                                       {       $$ = $2;        }
                                | decl_stmt
-                                       {       $$ = $1;        }
                                ;
 
-decl_stmt              : LESS_LESS any_identifier GREATER_GREATER
-                                       {       $$ = $2;        }
+decl_stmt              : decl_statement
                                | K_DECLARE
-                                       {       $$ = NULL;      }
-                               | decl_statement
-                                       {       $$ = NULL;      }
+                                       {
+                                               /* We allow useless extra DECLAREs */
+                                       }
+                               | LESS_LESS any_identifier GREATER_GREATER
+                                       {
+                                               /*
+                                                * Throw a helpful error if user tries to put block
+                                                * label just before BEGIN, instead of before DECLARE.
+                                                */
+                                               ereport(ERROR,
+                                                               (errcode(ERRCODE_SYNTAX_ERROR),
+                                                                errmsg("block label must be placed before DECLARE, not after"),
+                                                                parser_errposition(@1)));
+                                       }
                                ;
 
 decl_statement : decl_varname decl_const decl_datatype decl_notnull decl_defval