Fix ecpg bugs caused by missing semicolons in the backend grammar.

The Bison documentation clearly states that a semicolon is required
after every grammar rule, and our scripts that generate ecpg's
grammar from the backend's implicitly assumed this is true.  But it
turns out that only ancient versions of Bison actually enforce that.
There have been a couple of rules without trailing semicolons in
gram.y for some time, and as a consequence, ecpg's grammar was faulty
and produced wrong output for the affected statements.

To fix, add the missing semis, and add some cross-checks to ecpg's
scripts so that they'll bleat if we mess this up again.

The cases that were broken were:
* "SET variable = DEFAULT" (but not "SET variable TO DEFAULT"),
  as well as allied syntaxes such as ALTER SYSTEM SET ... DEFAULT.
  These produced syntactically invalid output that the server
  would reject.
* Multiple type names in DROP TYPE/DOMAIN commands.  Only the
  first type name would be listed in the emitted command.

Per report from Daisuke Higuchi.  Back-patch to all supported versions.

Discussion: https://postgr.es/m/1803D792815FC24D871C00D17AE95905DB51CE@g01jpexmbkw24

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index a68f78e0e0042335079fd2ccb5fcee41812fbb00..027901312030c7f3f6257d60d66c6461cf6c4711 100644 (file)
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -1465,6 +1465,7 @@ generic_set:
                                        n->name = $1;
                                        $$ = n;
                                }
+               ;
 
 set_rest_more: /* Generic SET syntaxes: */
                        generic_set                                             {$$ = $1;}
@@ -6282,6 +6283,7 @@ attrs:            '.' attr_name
 type_name_list:
                        Typename                                                                { $$ = list_make1($1); }
                        | type_name_list ',' Typename                   { $$ = lappend($1, $3); }
+               ;
 
 /*****************************************************************************
  *

diff --git a/src/interfaces/ecpg/preproc/check_rules.pl b/src/interfaces/ecpg/preproc/check_rules.pl
index 1388d057415ec4446c7351ac961b8d16e9ee7935..9d8c708d0f23f63f1a3c6e5ad849040cf5655e19 100644 (file)
--- a/src/interfaces/ecpg/preproc/check_rules.pl
+++ b/src/interfaces/ecpg/preproc/check_rules.pl
@@ -1,7 +1,7 @@
 #!/usr/bin/perl
 # src/interfaces/ecpg/preproc/check_rules.pl
 # test parser generator for ecpg
-# call with backend parser as stdin
+# call with backend grammar as stdin
 #
 # Copyright (c) 2009-2019, PostgreSQL Global Development Group
 #
@@ -47,6 +47,7 @@ my %replace_line = (
 
 my $block        = '';
 my $yaccmode     = 0;
+my $in_rule      = 0;
 my $brace_indent = 0;
 my (@arr, %found);
 my $comment     = 0;
@@ -131,10 +132,14 @@ while (<$parser_fh>)
                        $found{$block} = 1;
                        $cc++;
                        $block = '';
+                       $in_rule = 0 if $arr[$fieldIndexer] eq ';';
                }
                elsif (($arr[$fieldIndexer] =~ '[A-Za-z0-9]+:')
                        || $arr[ $fieldIndexer + 1 ] eq ':')
                {
+                       die "unterminated rule at grammar line $.\n"
+                         if $in_rule;
+                       $in_rule     = 1;
                        $non_term_id = $arr[$fieldIndexer];
                        $non_term_id =~ tr/://d;
                }
@@ -145,6 +150,9 @@ while (<$parser_fh>)
        }
 }
 
+die "unterminated rule at end of grammar\n"
+  if $in_rule;
+
 close $parser_fh;
 if ($verbose)
 {

diff --git a/src/interfaces/ecpg/preproc/parse.pl b/src/interfaces/ecpg/preproc/parse.pl
index 6dee5004ecae9407cd4208a93c94c0ee997f9def..6f67a5e942985f25f30b9067ad1f14560ec21641 100644 (file)
--- a/src/interfaces/ecpg/preproc/parse.pl
+++ b/src/interfaces/ecpg/preproc/parse.pl
@@ -22,6 +22,7 @@ $path = "." unless $path;
 my $copymode              = 0;
 my $brace_indent          = 0;
 my $yaccmode              = 0;
+my $in_rule               = 0;
 my $header_included       = 0;
 my $feature_not_supported = 0;
 my $tokenmode             = 0;
@@ -288,6 +289,7 @@ sub main
                                @fields  = ();
                                $infield = 0;
                                $line    = '';
+                               $in_rule = 0;
                                next;
                        }
 
@@ -365,6 +367,9 @@ sub main
                                $line    = '';
                                @fields  = ();
                                $infield = 1;
+                               die "unterminated rule at grammar line $.\n"
+                                 if $in_rule;
+                               $in_rule = 1;
                                next;
                        }
                        elsif ($copymode)
@@ -415,6 +420,8 @@ sub main
                        }
                }
        }
+       die "unterminated rule at end of grammar\n"
+         if $in_rule;
        return;
 }