gen_guc_tables.pl: Validate required GUC fields before code generation

Previously, gen_guc_tables.pl would emit "Use of uninitialized value" warnings if required fields were missing in guc_parameters.dat (for example, when an integer or real GUC omitted the 'max' value). The resulting error messages were unclear and did not identify which GUC entry was problematic. Add explicit validation of required fields depending on the parameter type, and fail with a clear and specific message such as: guc_parameters.dat:1909: error: entry "max_index_keys" of type "int" is missing required field "max" No changes to generated guc_tables.c. Author: Chao Li <lic@highgo.com> Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org> Reviewed-by: Peter Eisentraut <peter@eisentraut.org> Discussion: https://www.postgresql.org/message-id/flat/CAEoWx2%3DoP4LgHi771_OKhPPUS7B-CTqCs%3D%3DuQcNXWrwBoAm5Vg%40mail.gmail.com

Author: petere

src/backend/utils/misc/gen_guc_tables.pl

@@ -38,6 +38,52 @@ sub dquote
 return q{"} . $s =~ s/"/\\"/gr . q{"};
 }
 
+sub validate_guc_entry
+{
+my ($entry) = @_;
+
+my @required_common =
+ qw(name type context group short_desc variable boot_val);
+
+my %required_by_type = (
+int => [qw(min max)],
+real => [qw(min max)],
+enum => [qw(options)],
+bool => [], # no extra required fields
+string => [], # no extra required fields
+);
+
+for my $f (@required_common)
+{
+unless (defined $entry->{$f})
+{
+die sprintf(
+qq{%s:%d: error: entry "%s" is missing required field "%s"\n},
+$input_fname, $entry->{line_number},
+$entry->{name} // '<unknown>', $f);
+}
+}
+
+unless (exists $required_by_type{ $entry->{type} })
+{
+die sprintf(
+qq{%s:%d: error: entry "%s" has unrecognized GUC type "%s"\n},
+$input_fname, $entry->{line_number},
+$entry->{name}, $entry->{type} // '<unknown>');
+}
+
+for my $f (@{ $required_by_type{ $entry->{type} } })
+{
+unless (defined $entry->{$f})
+{
+die sprintf(
+qq{%s:%d: error: entry "%s" of type "%s" is missing required field "%s"\n},
+$input_fname, $entry->{line_number}, $entry->{name},
+$entry->{type}, $f);
+}
+}
+}
+
 # Print GUC table.
 sub print_table
 {
@@ -50,6 +96,8 @@ sub print_table
 
 foreach my $entry (@{$parse})
 {
+validate_guc_entry($entry);
+
 if (defined($prev_name) && lc($prev_name) ge lc($entry->{name}))
 {
 die sprintf(