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 a8ce22f31175cc6d78103cbe8a3a3a152a6060ca..53773a9e99a78c7e126e2608d2aeb8cb92f9e9cc 100644 (file)
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -1443,6 +1443,7 @@ generic_set:
                    n->name = $1;
                    $$ = n;
                }
+       ;
 
 set_rest_more: /* Generic SET syntaxes: */
            generic_set                         {$$ = $1;}
@@ -6192,6 +6193,7 @@ attrs:        '.' attr_name
 type_name_list:
            Typename                                { $$ = 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 e681943856b091e0c16a814454fd50f205259d48..b1501d0804e2b461fcca8b0e9de97195a9542e94 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 generater for ecpg
-# call with backend parser as stdin
+# test parser generator for ecpg
+# call with backend grammar as stdin
 #
 # Copyright (c) 2009-2017, 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 768df3a6b1c1cb1db31a1c4f410f7b8feccaa65a..7ed43e6a87fbbec35c2d3fc0ab0b3c2e44678796 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 +420,9 @@ sub main
            }
        }
    }
+   die "unterminated rule at end of grammar\n"
+     if $in_rule;
+   return;
 }