Rearrange use of plpgsql_add_initdatums() so that only the parsing of a

DECLARE section needs to know about it.  Formerly, everyplace besides DECLARE
that created variables needed to do "plpgsql_add_initdatums(NULL)" to prevent
those variables from being sucked up as part of a subsequent DECLARE block.
This is obviously error-prone, and in fact the SQLSTATE/SQLERRM patch had
failed to do it for those two variables, leading to the bug recently exhibited
by Asif Ali Rehman: a DECLARE within an exception handler tried to reinitialize
SQLERRM.

Although the SQLSTATE/SQLERRM patch isn't in any pre-8.1 branches, and so
I can't point to a demonstrable failure there, it seems wise to back-patch
this into the older branches anyway, just to keep the logic similar to HEAD.

2 files changed, 18 insertions, 17 deletions

diff --git a/src/pl/plpgsql/src/gram.y b/src/pl/plpgsql/src/gram.y
index 962fc59c4b8..d3775c46b9f 100644
--- a/src/pl/plpgsql/src/gram.y
+++ b/src/pl/plpgsql/src/gram.y
@@ -4,7 +4,7 @@
  *						  procedural language
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/pl/plpgsql/src/gram.y,v 1.39.2.3 2006/05/21 19:56:41 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/pl/plpgsql/src/gram.y,v 1.39.2.4 2007/02/08 18:38:28 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -263,7 +263,6 @@ decl_sect		: opt_label
 						$$.label	  = $1;
 						$$.n_initvars = 0;
 						$$.initvarnos = NULL;
-						plpgsql_add_initdatums(NULL);
 					}
 				| opt_label decl_start
 					{
@@ -271,7 +270,6 @@ decl_sect		: opt_label
 						$$.label	  = $1;
 						$$.n_initvars = 0;
 						$$.initvarnos = NULL;
-						plpgsql_add_initdatums(NULL);
 					}
 				| opt_label decl_start decl_stmts
 					{
@@ -280,12 +278,16 @@ decl_sect		: opt_label
 							$$.label = $3;
 						else
 							$$.label = $1;
+						/* Remember variables declared in decl_stmts */
 						$$.n_initvars = plpgsql_add_initdatums(&($$.initvarnos));
 					}
 				;
 
 decl_start		: K_DECLARE
 					{
+						/* Forget any variables created before block */
+						plpgsql_add_initdatums(NULL);
+						/* Make variable names be local to block */
 						plpgsql_ns_setlocal(true);
 					}
 				;
@@ -982,8 +984,6 @@ fori_var		: fori_varname
 						plpgsql_ns_additem(PLPGSQL_NSTYPE_VAR, new->varno,
 												$1.name);
 
-						plpgsql_add_initdatums(NULL);
-
 						$$ = new;
 					}
 				;
diff --git a/src/pl/plpgsql/src/pl_comp.c b/src/pl/plpgsql/src/pl_comp.c
index a2e116212bc..b92a69fb72a 100644
--- a/src/pl/plpgsql/src/pl_comp.c
+++ b/src/pl/plpgsql/src/pl_comp.c
@@ -3,7 +3,7 @@
  *			  procedural language
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.53.2.1 2003/01/31 00:32:00 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/pl/plpgsql/src/pl_comp.c,v 1.53.2.2 2007/02/08 18:38:28 tgl Exp $
  *
  *	  This software is copyrighted by Jan Wieck - Hamburg.
  *
@@ -504,12 +504,7 @@ plpgsql_compile(Oid fn_oid, int functype)
 	function->found_varno = var->varno;
 
 	/*
-	 * Forget about the above created variables
-	 */
-	plpgsql_add_initdatums(NULL);
-
-	/*
-	 * Now parse the functions text
+	 * Now parse the function's text
 	 */
 	parse_rc = plpgsql_yyparse();
 	if (parse_rc != 0)
@@ -1477,11 +1472,17 @@ plpgsql_adddatum(PLpgSQL_datum * new)
 
 
 /* ----------
- * plpgsql_add_initdatums		Put all datum entries created
- *					since the last call into the
- *					finishing code block so the
- *					block knows which variables to
- *					reinitialize when entered.
+ * plpgsql_add_initdatums		Make an array of the datum numbers of
+ *					all the simple VAR datums created since the last call
+ *					to this function.
+ *
+ * If varnos is NULL, we just forget any datum entries created since the
+ * last call.
+ *
+ * This is used around a DECLARE section to create a list of the VARs
+ * that have to be initialized at block entry.  Note that VARs can also
+ * be created elsewhere than DECLARE, eg by a FOR-loop, but it is then
+ * the responsibility of special-purpose code to initialize them.
  * ----------
  */
 int