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.

diff --git a/src/pl/plpgsql/src/gram.y b/src/pl/plpgsql/src/gram.y
index d2f8b16446757624ba01812eb88580cbb749b305..b3d5a2fe9b3ecdda03199067efc90e3677a7edc7 100644 (file)
--- a/src/pl/plpgsql/src/gram.y
+++ b/src/pl/plpgsql/src/gram.y
@@ -284,7 +284,6 @@ decl_sect           : opt_block_label
                                                $$.label          = $1;
                                                $$.n_initvars = 0;
                                                $$.initvarnos = NULL;
-                                               plpgsql_add_initdatums(NULL);
                                        }
                                | opt_block_label decl_start
                                        {
@@ -292,7 +291,6 @@ decl_sect           : opt_block_label
                                                $$.label          = $1;
                                                $$.n_initvars = 0;
                                                $$.initvarnos = NULL;
-                                               plpgsql_add_initdatums(NULL);
                                        }
                                | opt_block_label decl_start decl_stmts
                                        {
@@ -301,12 +299,16 @@ decl_sect         : opt_block_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);
                                        }
                                ;
@@ -948,9 +950,6 @@ for_control         :
                                                                                                                                                                  -1),
                                                                                                                   true);
 
-                                                               /* put the for-variable into the local block */
-                                                               plpgsql_add_initdatums(NULL);
-
                                                                new = palloc0(sizeof(PLpgSQL_stmt_fori));
                                                                new->cmd_type = PLPGSQL_STMT_FORI;
                                                                new->lineno   = $1;

diff --git a/src/pl/plpgsql/src/pl_comp.c b/src/pl/plpgsql/src/pl_comp.c
index d1a8d29ba416fd23aa841cc81cd84ae5b50bf76a..d5211650b3e1aab7532b8d0719bc0d9ba0c551da 100644 (file)
--- a/src/pl/plpgsql/src/pl_comp.c
+++ b/src/pl/plpgsql/src/pl_comp.c
@@ -682,11 +682,6 @@ do_compile(FunctionCallInfo fcinfo,
                                                                 true);
        function->found_varno = var->dno;
 
-       /*
-        * Forget about the above created variables
-        */
-       plpgsql_add_initdatums(NULL);
-
        /*
         * Now parse the function's text
         */
@@ -2003,11 +1998,17 @@ 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