Proposed patch to fix plpgsql's handling of block labels - Mailing list pgsql-patches

Per recent discussion, plpgsql's handling of block labels is not very
desirable: it will recognize unqualified identifiers as being block
labels even in contexts where a block label is illegal, and it will
prefer a match involving a block label over one that doesn't, even
when the second match is in a more closely nested scope and so should
take precedence over the outer-block match.

It is important to fix this for 8.3 for two reasons:

* Our introduction of the function name as the outermost block label
has created a risk of breakage of existing functions that use a
variable named the same as the function, as illustrated here:
http://archives.postgresql.org/pgsql-hackers/2007-11/msg00423.php

* We had not documented the possibility of using a block label as a
variable qualifier in any previous release, so it's at least somewhat
unlikely that anyone is depending on the current behavior.  (If there
is any code that's using qualification at all, it's probably been
imported from Oracle and expects the Oracle behavior.)  But if we don't
fix it now, there may be code depending on the bogus behavior by the
time 8.4 rolls around.

The patch separates lookup of block labels from lookup of variables,
which is possible since we always know which type of name we want to
find.  There's also some marginal cleanup of ugly/inconsistent coding
in plpgsql_parse_wordtype and friends.

Comments, objections?

            regards, tom lane

Index: gram.y
===================================================================
RCS file: /cvsroot/pgsql/src/pl/plpgsql/src/gram.y,v
retrieving revision 1.106
diff -c -r1.106 gram.y
*** gram.y    9 Nov 2007 23:58:32 -0000    1.106
--- gram.y    26 Nov 2007 21:36:11 -0000
***************
*** 43,48 ****
--- 43,49 ----
                                             int lineno);
  static    void             check_sql_expr(const char *stmt);
  static    void             plpgsql_sql_error_callback(void *arg);
+ static    char            *check_label(const char *yytxt);
  static    void             check_labels(const char *start_label,
                                        const char *end_label);

***************
*** 214,220 ****
  %token    T_ROW
  %token    T_RECORD
  %token    T_DTYPE
- %token    T_LABEL
  %token    T_WORD
  %token    T_ERROR

--- 215,220 ----
***************
*** 505,511 ****
                              yyerror("only positional parameters can be aliased");

                          plpgsql_ns_setlocal(false);
!                         nsi = plpgsql_ns_lookup(name, NULL);
                          if (nsi == NULL)
                          {
                              plpgsql_error_lineno = plpgsql_scanner_lineno();
--- 505,512 ----
                              yyerror("only positional parameters can be aliased");

                          plpgsql_ns_setlocal(false);
!
!                         nsi = plpgsql_ns_lookup(name, NULL, NULL, NULL);
                          if (nsi == NULL)
                          {
                              plpgsql_error_lineno = plpgsql_scanner_lineno();
***************
*** 1642,1661 ****
                      }
                  ;

  opt_label    :
                      {
                          $$ = NULL;
                      }
!                 | T_LABEL
                      {
!                         char *label_name;
!                         plpgsql_convert_ident(yytext, &label_name, 1);
!                         $$ = label_name;
                      }
!                 | T_WORD
                      {
!                         /* just to give a better error than "syntax error" */
!                         yyerror("no such label");
                      }
                  ;

--- 1643,1670 ----
                      }
                  ;

+ /*
+  * need all the options because scanner will have tried to resolve as variable
+  */
  opt_label    :
                      {
                          $$ = NULL;
                      }
!                 | T_WORD
!                     {
!                         $$ = check_label(yytext);
!                     }
!                 | T_SCALAR
                      {
!                         $$ = check_label(yytext);
                      }
!                 | T_RECORD
                      {
!                         $$ = check_label(yytext);
!                     }
!                 | T_ROW
!                     {
!                         $$ = check_label(yytext);
                      }
                  ;

***************
*** 2484,2489 ****
--- 2493,2509 ----
      errposition(0);
  }

+ static char *
+ check_label(const char *yytxt)
+ {
+     char       *label_name;
+
+     plpgsql_convert_ident(yytxt, &label_name, 1);
+     if (plpgsql_ns_lookup_label(label_name) == NULL)
+         yyerror("no such label");
+     return label_name;
+ }
+
  static void
  check_labels(const char *start_label, const char *end_label)
  {
Index: pl_comp.c
===================================================================
RCS file: /cvsroot/pgsql/src/pl/plpgsql/src/pl_comp.c,v
retrieving revision 1.119
diff -c -r1.119 pl_comp.c
*** pl_comp.c    15 Nov 2007 21:14:46 -0000    1.119
--- pl_comp.c    26 Nov 2007 21:36:11 -0000
***************
*** 787,793 ****
   * ----------
   */
  int
! plpgsql_parse_word(char *word)
  {
      PLpgSQL_nsitem *nse;
      char       *cp[1];
--- 787,793 ----
   * ----------
   */
  int
! plpgsql_parse_word(const char *word)
  {
      PLpgSQL_nsitem *nse;
      char       *cp[1];
***************
*** 797,802 ****
--- 797,803 ----

      /*
       * Recognize tg_argv when compiling triggers
+      * (XXX this sucks, it should be a regular variable in the namestack)
       */
      if (plpgsql_curr_compile->fn_functype == T_TRIGGER)
      {
***************
*** 825,839 ****
      /*
       * Do a lookup on the compiler's namestack
       */
!     nse = plpgsql_ns_lookup(cp[0], NULL);
      if (nse != NULL)
      {
-         pfree(cp[0]);
          switch (nse->itemtype)
          {
-             case PLPGSQL_NSTYPE_LABEL:
-                 return T_LABEL;
-
              case PLPGSQL_NSTYPE_VAR:
                  plpgsql_yylval.scalar = plpgsql_Datums[nse->itemno];
                  return T_SCALAR;
--- 826,838 ----
      /*
       * Do a lookup on the compiler's namestack
       */
!     nse = plpgsql_ns_lookup(cp[0], NULL, NULL, NULL);
!     pfree(cp[0]);
!
      if (nse != NULL)
      {
          switch (nse->itemtype)
          {
              case PLPGSQL_NSTYPE_VAR:
                  plpgsql_yylval.scalar = plpgsql_Datums[nse->itemno];
                  return T_SCALAR;
***************
*** 855,861 ****
       * Nothing found - up to now it's a word without any special meaning for
       * us.
       */
-     pfree(cp[0]);
      return T_WORD;
  }

--- 854,859 ----
***************
*** 866,883 ****
   * ----------
   */
  int
! plpgsql_parse_dblword(char *word)
  {
      PLpgSQL_nsitem *ns;
      char       *cp[2];

      /* Do case conversion and word separation */
      plpgsql_convert_ident(word, cp, 2);

      /*
!      * Lookup the first word
       */
!     ns = plpgsql_ns_lookup(cp[0], NULL);
      if (ns == NULL)
      {
          pfree(cp[0]);
--- 864,882 ----
   * ----------
   */
  int
! plpgsql_parse_dblword(const char *word)
  {
      PLpgSQL_nsitem *ns;
      char       *cp[2];
+     int            nnames;

      /* Do case conversion and word separation */
      plpgsql_convert_ident(word, cp, 2);

      /*
!      * Do a lookup on the compiler's namestack
       */
!     ns = plpgsql_ns_lookup(cp[0], cp[1], NULL, &nnames);
      if (ns == NULL)
      {
          pfree(cp[0]);
***************
*** 887,925 ****

      switch (ns->itemtype)
      {
!         case PLPGSQL_NSTYPE_LABEL:
!
!             /*
!              * First word is a label, so second word could be a variable,
!              * record or row in that bodies namestack. Anything else could
!              * only be something in a query given to the SPI manager and
!              * T_ERROR will get eaten up by the collector routines.
!              */
!             ns = plpgsql_ns_lookup(cp[1], cp[0]);
              pfree(cp[0]);
              pfree(cp[1]);
!             if (ns == NULL)
!                 return T_ERROR;
!             switch (ns->itemtype)
!             {
!                 case PLPGSQL_NSTYPE_VAR:
!                     plpgsql_yylval.scalar = plpgsql_Datums[ns->itemno];
!                     return T_SCALAR;
!
!                 case PLPGSQL_NSTYPE_REC:
!                     plpgsql_yylval.rec = (PLpgSQL_rec *) (plpgsql_Datums[ns->itemno]);
!                     return T_RECORD;
!
!                 case PLPGSQL_NSTYPE_ROW:
!                     plpgsql_yylval.row = (PLpgSQL_row *) (plpgsql_Datums[ns->itemno]);
!                     return T_ROW;
!
!                 default:
!                     return T_ERROR;
!             }
!             break;

          case PLPGSQL_NSTYPE_REC:
              {
                  /*
                   * First word is a record name, so second word must be a field
--- 886,900 ----

      switch (ns->itemtype)
      {
!         case PLPGSQL_NSTYPE_VAR:
!             /* Block-qualified reference to scalar variable. */
!             plpgsql_yylval.scalar = plpgsql_Datums[ns->itemno];
              pfree(cp[0]);
              pfree(cp[1]);
!             return T_SCALAR;

          case PLPGSQL_NSTYPE_REC:
+             if (nnames == 1)
              {
                  /*
                   * First word is a record name, so second word must be a field
***************
*** 940,947 ****
--- 915,931 ----
                  pfree(cp[1]);
                  return T_SCALAR;
              }
+             else
+             {
+                 /* Block-qualified reference to record variable. */
+                 plpgsql_yylval.rec = (PLpgSQL_rec *) (plpgsql_Datums[ns->itemno]);
+                 pfree(cp[0]);
+                 pfree(cp[1]);
+                 return T_RECORD;
+             }

          case PLPGSQL_NSTYPE_ROW:
+             if (nnames == 1)
              {
                  /*
                   * First word is a row name, so second word must be a field in
***************
*** 967,972 ****
--- 951,964 ----
                           errmsg("row \"%s\" has no field \"%s\"",
                                  cp[0], cp[1])));
              }
+             else
+             {
+                 /* Block-qualified reference to row variable. */
+                 plpgsql_yylval.row = (PLpgSQL_row *) (plpgsql_Datums[ns->itemno]);
+                 pfree(cp[0]);
+                 pfree(cp[1]);
+                 return T_ROW;
+             }

          default:
              break;
***************
*** 984,1021 ****
   * ----------
   */
  int
! plpgsql_parse_tripword(char *word)
  {
      PLpgSQL_nsitem *ns;
      char       *cp[3];

      /* Do case conversion and word separation */
      plpgsql_convert_ident(word, cp, 3);

      /*
!      * Lookup the first word - it must be a label
!      */
!     ns = plpgsql_ns_lookup(cp[0], NULL);
!     if (ns == NULL)
!     {
!         pfree(cp[0]);
!         pfree(cp[1]);
!         pfree(cp[2]);
!         return T_ERROR;
!     }
!     if (ns->itemtype != PLPGSQL_NSTYPE_LABEL)
!     {
!         pfree(cp[0]);
!         pfree(cp[1]);
!         pfree(cp[2]);
!         return T_ERROR;
!     }
!
!     /*
!      * First word is a label, so second word could be a record or row
       */
!     ns = plpgsql_ns_lookup(cp[1], cp[0]);
!     if (ns == NULL)
      {
          pfree(cp[0]);
          pfree(cp[1]);
--- 976,996 ----
   * ----------
   */
  int
! plpgsql_parse_tripword(const char *word)
  {
      PLpgSQL_nsitem *ns;
      char       *cp[3];
+     int            nnames;

      /* Do case conversion and word separation */
      plpgsql_convert_ident(word, cp, 3);

      /*
!      * Do a lookup on the compiler's namestack.
!      * Must find a qualified reference.
       */
!     ns = plpgsql_ns_lookup(cp[0], cp[1], cp[2], &nnames);
!     if (ns == NULL || nnames != 2)
      {
          pfree(cp[0]);
          pfree(cp[1]);
***************
*** 1028,1034 ****
          case PLPGSQL_NSTYPE_REC:
              {
                  /*
!                  * This word is a record name, so third word must be a field
                   * in this record.
                   */
                  PLpgSQL_recfield *new;
--- 1003,1009 ----
          case PLPGSQL_NSTYPE_REC:
              {
                  /*
!                  * words 1/2 are a record name, so third word must be a field
                   * in this record.
                   */
                  PLpgSQL_recfield *new;
***************
*** 1052,1058 ****
          case PLPGSQL_NSTYPE_ROW:
              {
                  /*
!                  * This word is a row name, so third word must be a field in
                   * this row.
                   */
                  PLpgSQL_row *row;
--- 1027,1033 ----
          case PLPGSQL_NSTYPE_ROW:
              {
                  /*
!                  * words 1/2 are a row name, so third word must be a field in
                   * this row.
                   */
                  PLpgSQL_row *row;
***************
*** 1114,1124 ****
      pfree(cp[1]);

      /*
!      * Do a lookup on the compiler's namestack. But ensure it moves up to the
!      * toplevel.
       */
      old_nsstate = plpgsql_ns_setlocal(false);
!     nse = plpgsql_ns_lookup(cp[0], NULL);
      plpgsql_ns_setlocal(old_nsstate);

      if (nse != NULL)
--- 1089,1098 ----
      pfree(cp[1]);

      /*
!      * Do a lookup on the compiler's namestack.  Ensure we scan all levels.
       */
      old_nsstate = plpgsql_ns_setlocal(false);
!     nse = plpgsql_ns_lookup(cp[0], NULL, NULL, NULL);
      plpgsql_ns_setlocal(old_nsstate);

      if (nse != NULL)
***************
*** 1200,1231 ****
      word[i] = '.';
      plpgsql_convert_ident(word, cp, 3);
      word[i] = '%';

      /*
!      * Lookup the first word
       */
!     nse = plpgsql_ns_lookup(cp[0], NULL);

!     /*
!      * If this is a label lookup the second word in that label's namestack
!      * level
!      */
!     if (nse != NULL)
      {
!         if (nse->itemtype == PLPGSQL_NSTYPE_LABEL)
!         {
!             old_nsstate = plpgsql_ns_setlocal(false);
!             nse = plpgsql_ns_lookup(cp[1], cp[0]);
!             plpgsql_ns_setlocal(old_nsstate);
!
!             if (nse != NULL && nse->itemtype == PLPGSQL_NSTYPE_VAR)
!             {
!                 plpgsql_yylval.dtype = ((PLpgSQL_var *) (plpgsql_Datums[nse->itemno]))->datatype;
!                 result = T_DTYPE;
!             }
!         }
!
!         /* Return T_ERROR if not found, otherwise T_DTYPE */
          goto done;
      }

--- 1174,1194 ----
      word[i] = '.';
      plpgsql_convert_ident(word, cp, 3);
      word[i] = '%';
+     pfree(cp[2]);

      /*
!      * Do a lookup on the compiler's namestack.  Ensure we scan all levels.
!      * We don't need to check number of names matched, because we will only
!      * consider scalar variables.
       */
!     old_nsstate = plpgsql_ns_setlocal(false);
!     nse = plpgsql_ns_lookup(cp[0], cp[1], NULL, NULL);
!     plpgsql_ns_setlocal(old_nsstate);

!     if (nse != NULL && nse->itemtype == PLPGSQL_NSTYPE_VAR)
      {
!         plpgsql_yylval.dtype = ((PLpgSQL_var *) (plpgsql_Datums[nse->itemno]))->datatype;
!         result = T_DTYPE;
          goto done;
      }

***************
*** 1291,1298 ****
   * plpgsql_parse_tripwordtype        Same lookup for word.word.word%TYPE
   * ----------
   */
- #define TYPE_JUNK_LEN    5
-
  int
  plpgsql_parse_tripwordtype(char *word)
  {
--- 1254,1259 ----
***************
*** 1302,1311 ****
      HeapTuple    typetup = NULL;
      Form_pg_class classStruct;
      Form_pg_attribute attrStruct;
!     char       *cp[2];
!     char       *colname[1];
!     int            qualified_att_len;
!     int            numdots = 0;
      int            i;
      RangeVar   *relvar;
      MemoryContext oldCxt;
--- 1263,1269 ----
      HeapTuple    typetup = NULL;
      Form_pg_class classStruct;
      Form_pg_attribute attrStruct;
!     char       *cp[4];
      int            i;
      RangeVar   *relvar;
      MemoryContext oldCxt;
***************
*** 1315,1341 ****
      oldCxt = MemoryContextSwitchTo(compile_tmp_cxt);

      /* Do case conversion and word separation */
!     qualified_att_len = strlen(word) - TYPE_JUNK_LEN;
!     Assert(word[qualified_att_len] == '%');
!
!     for (i = 0; i < qualified_att_len; i++)
!     {
!         if (word[i] == '.' && ++numdots == 2)
!             break;
!     }
!
!     cp[0] = (char *) palloc((i + 1) * sizeof(char));
!     memcpy(cp[0], word, i * sizeof(char));
!     cp[0][i] = '\0';
!
!     /*
!      * qualified_att_len - one based position + 1 (null terminator)
!      */
!     cp[1] = (char *) palloc((qualified_att_len - i) * sizeof(char));
!     memcpy(cp[1], &word[i + 1], (qualified_att_len - i - 1) * sizeof(char));
!     cp[1][qualified_att_len - i - 1] = '\0';

!     relvar = makeRangeVarFromNameList(stringToQualifiedNameList(cp[0]));
      classOid = RangeVarGetRelid(relvar, true);
      if (!OidIsValid(classOid))
          goto done;
--- 1273,1287 ----
      oldCxt = MemoryContextSwitchTo(compile_tmp_cxt);

      /* Do case conversion and word separation */
!     /* We convert %type to .type momentarily to keep converter happy */
!     i = strlen(word) - 5;
!     Assert(word[i] == '%');
!     word[i] = '.';
!     plpgsql_convert_ident(word, cp, 4);
!     word[i] = '%';
!     pfree(cp[3]);

!     relvar = makeRangeVar(cp[0], cp[1]);
      classOid = RangeVarGetRelid(relvar, true);
      if (!OidIsValid(classOid))
          goto done;
***************
*** 1359,1366 ****
      /*
       * Fetch the named table field and its type
       */
!     plpgsql_convert_ident(cp[1], colname, 1);
!     attrtup = SearchSysCacheAttName(classOid, colname[0]);
      if (!HeapTupleIsValid(attrtup))
          goto done;
      attrStruct = (Form_pg_attribute) GETSTRUCT(attrtup);
--- 1305,1311 ----
      /*
       * Fetch the named table field and its type
       */
!     attrtup = SearchSysCacheAttName(classOid, cp[2]);
      if (!HeapTupleIsValid(attrtup))
          goto done;
      attrStruct = (Form_pg_attribute) GETSTRUCT(attrtup);
***************
*** 1436,1448 ****
   *            So word must be a namespace qualified table name.
   * ----------
   */
- #define ROWTYPE_JUNK_LEN    8
-
  int
  plpgsql_parse_dblwordrowtype(char *word)
  {
      Oid            classOid;
!     char       *cp;
      int            i;
      RangeVar   *relvar;
      MemoryContext oldCxt;
--- 1381,1391 ----
   *            So word must be a namespace qualified table name.
   * ----------
   */
  int
  plpgsql_parse_dblwordrowtype(char *word)
  {
      Oid            classOid;
!     char       *cp[3];
      int            i;
      RangeVar   *relvar;
      MemoryContext oldCxt;
***************
*** 1452,1470 ****

      /* Do case conversion and word separation */
      /* We convert %rowtype to .rowtype momentarily to keep converter happy */
!     i = strlen(word) - ROWTYPE_JUNK_LEN;
      Assert(word[i] == '%');
!     word[i] = '\0';
!     cp = pstrdup(word);
      word[i] = '%';

      /* Lookup the relation */
!     relvar = makeRangeVarFromNameList(stringToQualifiedNameList(cp));
      classOid = RangeVarGetRelid(relvar, true);
      if (!OidIsValid(classOid))
          ereport(ERROR,
                  (errcode(ERRCODE_UNDEFINED_TABLE),
!                  errmsg("relation \"%s\" does not exist", cp)));

      /* Build and return the row type struct */
      plpgsql_yylval.dtype = plpgsql_build_datatype(get_rel_type_id(classOid),
--- 1395,1413 ----

      /* Do case conversion and word separation */
      /* We convert %rowtype to .rowtype momentarily to keep converter happy */
!     i = strlen(word) - 8;
      Assert(word[i] == '%');
!     word[i] = '.';
!     plpgsql_convert_ident(word, cp, 3);
      word[i] = '%';

      /* Lookup the relation */
!     relvar = makeRangeVar(cp[0], cp[1]);
      classOid = RangeVarGetRelid(relvar, true);
      if (!OidIsValid(classOid))
          ereport(ERROR,
                  (errcode(ERRCODE_UNDEFINED_TABLE),
!                  errmsg("relation \"%s.%s\" does not exist", cp[0], cp[1])));

      /* Build and return the row type struct */
      plpgsql_yylval.dtype = plpgsql_build_datatype(get_rel_type_id(classOid),
Index: pl_funcs.c
===================================================================
RCS file: /cvsroot/pgsql/src/pl/plpgsql/src/pl_funcs.c,v
retrieving revision 1.65
diff -c -r1.65 pl_funcs.c
*** pl_funcs.c    15 Nov 2007 22:25:17 -0000    1.65
--- pl_funcs.c    26 Nov 2007 21:36:11 -0000
***************
*** 126,134 ****


  /* ----------
!  * plpgsql_ns_setlocal            Tell plpgsql_ns_lookup to or to
!  *                    not look into the current level
!  *                    only.
   * ----------
   */
  bool
--- 126,140 ----


  /* ----------
!  * plpgsql_ns_setlocal            Tell plpgsql_ns_lookup whether to
!  *                    look into the current level only.
!  *
!  * This is a crock, but in the current design we need it because scan.l
!  * initiates name lookup, and the scanner does not know whether we are
!  * examining a name being declared in a DECLARE section.  For that case
!  * we only want to know if there is a conflicting name earlier in the
!  * same DECLARE section.  So the grammar must temporarily set local mode
!  * before scanning decl_varnames.
   * ----------
   */
  bool
***************
*** 219,277 ****


  /* ----------
!  * plpgsql_ns_lookup            Lookup for a word in the namestack
   * ----------
   */
  PLpgSQL_nsitem *
! plpgsql_ns_lookup(const char *name, const char *label)
  {
      PLpgSQL_ns *ns;
      int            i;

!     /*
!      * If a label is specified, lookup only in that
!      */
!     if (label != NULL)
      {
!         for (ns = ns_current; ns != NULL; ns = ns->upper)
          {
!             if (strcmp(ns->items[0]->name, label) == 0)
              {
!                 for (i = 1; i < ns->items_used; i++)
                  {
!                     if (strcmp(ns->items[i]->name, name) == 0)
!                         return ns->items[i];
                  }
-                 return NULL;    /* name not found in specified label */
              }
          }
!         return NULL;            /* label not found */
      }

!     /*
!      * No label given, lookup for visible labels ignoring localmode
!      */
      for (ns = ns_current; ns != NULL; ns = ns->upper)
      {
          if (strcmp(ns->items[0]->name, name) == 0)
              return ns->items[0];
      }

!     /*
!      * Finally lookup name in the namestack
!      */
!     for (ns = ns_current; ns != NULL; ns = ns->upper)
!     {
!         for (i = 1; i < ns->items_used; i++)
!         {
!             if (strcmp(ns->items[i]->name, name) == 0)
!                 return ns->items[i];
!         }
!         if (ns_localmode)
!             return NULL;        /* name not found in current namespace */
!     }
!
!     return NULL;
  }


--- 225,322 ----


  /* ----------
!  * plpgsql_ns_lookup            Lookup an identifier in the namestack
!  *
!  * Note that this only searches for variables, not labels.
!  *
!  * name1 must be non-NULL.  Pass NULL for name2 and/or name3 if parsing a name
!  * with fewer than three components.
!  *
!  * If names_used isn't NULL, *names_used receives the number of names
!  * matched: 0 if no match, 1 if name1 matched an unqualified variable name,
!  * 2 if name1 and name2 matched a block label + variable name.
!  *
!  * Note that name3 is never directly matched to anything.  However, if it
!  * isn't NULL, we will disregard qualified matches to scalar variables.
!  * Similarly, if name2 isn't NULL, we disregard unqualified matches to
!  * scalar variables.
   * ----------
   */
  PLpgSQL_nsitem *
! plpgsql_ns_lookup(const char *name1, const char *name2, const char *name3,
!                   int *names_used)
  {
      PLpgSQL_ns *ns;
      int            i;

!     /* Scan each level of the namestack */
!     for (ns = ns_current; ns != NULL; ns = ns->upper)
      {
!         /* Check for unqualified match to variable name */
!         for (i = 1; i < ns->items_used; i++)
!         {
!             PLpgSQL_nsitem *nsitem = ns->items[i];
!
!             if (strcmp(nsitem->name, name1) == 0)
!             {
!                 if (name2 == NULL ||
!                     nsitem->itemtype != PLPGSQL_NSTYPE_VAR)
!                 {
!                     if (names_used)
!                         *names_used = 1;
!                     return nsitem;
!                 }
!             }
!         }
!
!         /* Check for qualified match to variable name */
!         if (name2 != NULL &&
!             strcmp(ns->items[0]->name, name1) == 0)
          {
!             for (i = 1; i < ns->items_used; i++)
              {
!                 PLpgSQL_nsitem *nsitem = ns->items[i];
!
!                 if (strcmp(nsitem->name, name2) == 0)
                  {
!                     if (name3 == NULL ||
!                         nsitem->itemtype != PLPGSQL_NSTYPE_VAR)
!                     {
!                         if (names_used)
!                             *names_used = 2;
!                         return nsitem;
!                     }
                  }
              }
          }
!
!         if (ns_localmode)
!             break;                /* do not look into upper levels */
      }

!     /* This is just to suppress possibly-uninitialized-variable warnings */
!     if (names_used)
!         *names_used = 0;
!     return NULL;                /* No match found */
! }
!
!
! /* ----------
!  * plpgsql_ns_lookup_label        Lookup a label in the namestack
!  * ----------
!  */
! PLpgSQL_nsitem *
! plpgsql_ns_lookup_label(const char *name)
! {
!     PLpgSQL_ns *ns;
!
      for (ns = ns_current; ns != NULL; ns = ns->upper)
      {
          if (strcmp(ns->items[0]->name, name) == 0)
              return ns->items[0];
      }

!     return NULL;                /* label not found */
  }


***************
*** 846,853 ****
  dump_exit(PLpgSQL_stmt_exit *stmt)
  {
      dump_ind();
!     printf("%s label='%s'",
!            stmt->is_exit ? "EXIT" : "CONTINUE", stmt->label);
      if (stmt->cond != NULL)
      {
          printf(" WHEN ");
--- 891,899 ----
  dump_exit(PLpgSQL_stmt_exit *stmt)
  {
      dump_ind();
!     printf("%s", stmt->is_exit ? "EXIT" : "CONTINUE");
!     if (stmt->label != NULL)
!         printf(" label='%s'", stmt->label);
      if (stmt->cond != NULL)
      {
          printf(" WHEN ");
Index: plpgsql.h
===================================================================
RCS file: /cvsroot/pgsql/src/pl/plpgsql/src/plpgsql.h,v
retrieving revision 1.93
diff -c -r1.93 plpgsql.h
*** plpgsql.h    15 Nov 2007 22:25:17 -0000    1.93
--- plpgsql.h    26 Nov 2007 21:36:11 -0000
***************
*** 473,479 ****
      int            cmd_type;
      int            lineno;
      bool        is_exit;        /* Is this an exit or a continue? */
!     char       *label;
      PLpgSQL_expr *cond;
  } PLpgSQL_stmt_exit;

--- 473,479 ----
      int            cmd_type;
      int            lineno;
      bool        is_exit;        /* Is this an exit or a continue? */
!     char       *label;            /* NULL if it's an unlabelled EXIT/CONTINUE */
      PLpgSQL_expr *cond;
  } PLpgSQL_stmt_exit;

***************
*** 723,731 ****
   */
  extern PLpgSQL_function *plpgsql_compile(FunctionCallInfo fcinfo,
                  bool forValidator);
! extern int    plpgsql_parse_word(char *word);
! extern int    plpgsql_parse_dblword(char *word);
! extern int    plpgsql_parse_tripword(char *word);
  extern int    plpgsql_parse_wordtype(char *word);
  extern int    plpgsql_parse_dblwordtype(char *word);
  extern int    plpgsql_parse_tripwordtype(char *word);
--- 723,731 ----
   */
  extern PLpgSQL_function *plpgsql_compile(FunctionCallInfo fcinfo,
                  bool forValidator);
! extern int    plpgsql_parse_word(const char *word);
! extern int    plpgsql_parse_dblword(const char *word);
! extern int    plpgsql_parse_tripword(const char *word);
  extern int    plpgsql_parse_wordtype(char *word);
  extern int    plpgsql_parse_dblwordtype(char *word);
  extern int    plpgsql_parse_tripwordtype(char *word);
***************
*** 773,779 ****
  extern char *plpgsql_dstring_get(PLpgSQL_dstring *ds);

  /* ----------
!  * Functions for the namestack handling in pl_funcs.c
   * ----------
   */
  extern void plpgsql_ns_init(void);
--- 773,779 ----
  extern char *plpgsql_dstring_get(PLpgSQL_dstring *ds);

  /* ----------
!  * Functions for namestack handling in pl_funcs.c
   * ----------
   */
  extern void plpgsql_ns_init(void);
***************
*** 781,787 ****
  extern void plpgsql_ns_push(const char *label);
  extern void plpgsql_ns_pop(void);
  extern void plpgsql_ns_additem(int itemtype, int itemno, const char *name);
! extern PLpgSQL_nsitem *plpgsql_ns_lookup(const char *name, const char *nsname);
  extern void plpgsql_ns_rename(char *oldname, char *newname);

  /* ----------
--- 781,789 ----
  extern void plpgsql_ns_push(const char *label);
  extern void plpgsql_ns_pop(void);
  extern void plpgsql_ns_additem(int itemtype, int itemno, const char *name);
! extern PLpgSQL_nsitem *plpgsql_ns_lookup(const char *name1, const char *name2,
!                                          const char *name3, int *names_used);
! extern PLpgSQL_nsitem *plpgsql_ns_lookup_label(const char *name);
  extern void plpgsql_ns_rename(char *oldname, char *newname);

  /* ----------