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 9d652a3e1006488c2b107a1c3ce2dd81b6fb92ae..bc65319c2c46b5f7cf2fdf74132df869badefb2a 100644 (file)
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -1467,6 +1467,7 @@ generic_set:
                    n->name = $1;
                    $$ = n;
                }
+       ;
 
 set_rest_more: /* Generic SET syntaxes: */
            generic_set                         {$$ = $1;}
@@ -6375,6 +6376,7 @@ attrs:        '.' attr_name
 type_name_list:
            Typename                                { $$ = 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 6c8b00485464955a932ba261b6c679ae85af2396..c6a183ec71160a151a5047320770824fdbd2512b 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) 2009-2018, 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 ad87aad28358fdba72601e65b73b38c0edcfd489..863d770e109fb69a0bb2e00f56bdfce0303bd9ae 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;
 }