Clarify handling of special-case values in bootstrap catalog data.

I (tgl) originally coded the special case for pg_proc.pronargs as
though it were a kind of default value.  It seems better though to
treat computable columns as an independent concern: this makes the
code clearer, and probably a bit faster too since we needn't do
work inside the per-column loop.

Improve related comments, as well, in the expectation that there
might be more cases like this in future.

John Naylor, some additional comment-hacking by me

Discussion: https://postgr.es/m/CAJVSVGW-D7OobzU=dybVT2JqZAx-4X1yvBJdavBmqQL05Q6CLw@mail.gmail.com

diff --git a/src/backend/catalog/Catalog.pm b/src/backend/catalog/Catalog.pm
index 67d17197f9e1faf32b4fc66e7d80277b96545fef..eee7cb3b90e0e433b569b1c34b32be13a9e910cc 100644 (file)
--- a/src/backend/catalog/Catalog.pm
+++ b/src/backend/catalog/Catalog.pm
@@ -292,6 +292,21 @@ sub AddDefaultValues
        my ($row, $schema, $catname) = @_;
        my @missing_fields;
 
+       # Compute special-case column values.
+       # Note: If you add new cases here, you must also teach
+       # strip_default_values() in include/catalog/reformat_dat_file.pl
+       # to delete them.
+       if ($catname eq 'pg_proc')
+       {
+               # pg_proc.pronargs can be derived from proargtypes.
+               if (defined $row->{proargtypes})
+               {
+                       my @proargtypes = split /\s+/, $row->{proargtypes};
+                       $row->{pronargs} = scalar(@proargtypes);
+               }
+       }
+
+       # Now fill in defaults, and note any columns that remain undefined.
        foreach my $column (@$schema)
        {
                my $attname = $column->{name};
@@ -305,14 +320,6 @@ sub AddDefaultValues
                {
                        $row->{$attname} = $column->{default};
                }
-               elsif ($catname eq 'pg_proc'
-                       && $attname eq 'pronargs'
-                       && defined($row->{proargtypes}))
-               {
-                       # pg_proc.pronargs can be derived from proargtypes.
-                       my @proargtypes = split /\s+/, $row->{proargtypes};
-                       $row->{$attname} = scalar(@proargtypes);
-               }
                else
                {
                        # Failed to find a value.
@@ -320,6 +327,7 @@ sub AddDefaultValues
                }
        }
 
+       # Failure to provide all columns is a hard error.
        if (@missing_fields)
        {
                die sprintf "missing values for field(s) %s in %s.dat line %s\n",

diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index f643f564a6b8b4ada81987f9da5829dc15a0d70e..66c6c224a8be7a8e8ad78fcb816408b894adf172 100644 (file)
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -30,6 +30,9 @@
 # "convert srctypename to desttypename" for cast functions
 # "less-equal-greater" for B-tree comparison functions
 
+# Note: pronargs is computed when this file is read, so it does not need
+# to be specified in entries here.  See AddDefaultValues() in Catalog.pm.
+
 # Once upon a time these entries were ordered by OID.  Lately it's often
 # been the custom to insert new entries adjacent to related older entries.
 # Try to do one or the other though, don't just insert entries at random.

diff --git a/src/include/catalog/reformat_dat_file.pl b/src/include/catalog/reformat_dat_file.pl
index 8ebbec6c541670ca63c6d134c35a0d51dbf6deff..4d2523c1bf41370201e672168fca69abb510c0e6 100644 (file)
--- a/src/include/catalog/reformat_dat_file.pl
+++ b/src/include/catalog/reformat_dat_file.pl
@@ -177,31 +177,31 @@ foreach my $catname (@catnames)
        close $dat;
 }
 
-# Leave values out if there is a matching default.
+# Remove column values for which there is a matching default,
+# or if the value can be computed from other columns.
 sub strip_default_values
 {
        my ($row, $schema, $catname) = @_;
 
+       # Delete values that match defaults.
        foreach my $column (@$schema)
        {
                my $attname = $column->{name};
                die "strip_default_values: $catname.$attname undefined\n"
                  if !defined $row->{$attname};
 
-               # Delete values that match defaults.
                if (defined $column->{default}
                        and ($row->{$attname} eq $column->{default}))
                {
                        delete $row->{$attname};
                }
+       }
 
-               # Also delete pg_proc.pronargs, since that can be recomputed.
-               if (   $catname eq 'pg_proc'
-                       && $attname eq 'pronargs'
-                       && defined($row->{proargtypes}))
-               {
-                       delete $row->{$attname};
-               }
+       # Delete computed values.  See AddDefaultValues() in Catalog.pm.
+       # Note: This must be done after deleting values matching defaults.
+       if ($catname eq 'pg_proc')
+       {
+               delete $row->{pronargs} if defined $row->{proargtypes};
        }
 }