Fix version comparison in Version.pm

adunstan · adunstan · commit 97ee956416e9 · 2022-11-18T08:45:58.000-05:00
Version strings with unequal numbers of parts were being compared incorrectly. We cure this by treating a missing part in the shorter version as 0. per complaint from Jehan-Guillaume de Rorthais, but the fix is mine, not his. Discussion: https://postgr.es/m/20220628225325.53d97b8d@karst Backpatch to release 14 where this code was introduced.
diff --git a/src/test/perl/PostgreSQL/Version.pm b/src/test/perl/PostgreSQL/Version.pm
@@ -123,9 +123,12 @@ sub _version_cmp
 
 	for (my $idx = 0;; $idx++)
 	{
-		return 0 unless (defined $an->[$idx] && defined $bn->[$idx]);
-		return $an->[$idx] <=> $bn->[$idx]
-		  if ($an->[$idx] <=> $bn->[$idx]);
+		return 0
+		  if ($idx >= @$an && $idx >= @$bn);
+		# treat a missing number as 0
+		my ($anum, $bnum) = ($an->[$idx] || 0, $bn->[$idx] || 0);
+		return $anum <=> $bnum
+		  if ($anum <=> $bnum);
 	}
 }
 

Original file line number	Diff line number	Diff line change
`@@ -123,9 +123,12 @@ sub _version_cmp`
`123`	`123`
`124`	`124`	`for (my $idx = 0;; $idx++)`
`125`	`125`	`{`
`126`		`- return 0 unless (defined $an->[$idx] && defined $bn->[$idx]);`
`127`		`- return $an->[$idx] <=> $bn->[$idx]`
`128`		`- if ($an->[$idx] <=> $bn->[$idx]);`
	`126`	`+ return 0`
	`127`	`+ if ($idx >= @$an && $idx >= @$bn);`
	`128`	`+ # treat a missing number as 0`
	`129`	`+ my ($anum, $bnum) = ($an->[$idx] \|\| 0, $bn->[$idx] \|\| 0);`
	`130`	`+ return $anum <=> $bnum`
	`131`	`+ if ($anum <=> $bnum);`
`129`	`132`	`}`
`130`	`133`	`}`
`131`	`134`