Avoid getting bit by roundoff error while checking $Safe::VERSION.

tglsfdc · tglsfdc · commit 5597fee8d701 · 2004-11-24T18:47:38.000Z
Per report from Mark Kirkwood.
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
@@ -33,7 +33,7 @@
  *	  ENHANCEMENTS, OR MODIFICATIONS.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.63 2004/11/23 00:21:17 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.64 2004/11/24 18:47:38 tgl Exp $
  *
  **********************************************************************/
 
@@ -238,13 +238,18 @@ plperl_safe_init(void)
 			   ;
 
 	SV		   *res;
-	float		safe_version;
+	double		safe_version;
 
 	res = eval_pv(safe_module, FALSE);	/* TRUE = croak if failure */
 
 	safe_version = SvNV(res);
 
-	eval_pv((safe_version < 2.09 ? safe_bad : safe_ok), FALSE);
+	/*
+	 * We actually want to reject safe_version < 2.09, but it's risky to
+	 * assume that floating-point comparisons are exact, so use a slightly
+	 * smaller comparison value.
+	 */
+	eval_pv((safe_version < 2.0899 ? safe_bad : safe_ok), FALSE);
 
 	plperl_safe_init_done = true;
 }

Original file line number	Diff line number	Diff line change
`@@ -33,7 +33,7 @@`
`33`	`33`	`* ENHANCEMENTS, OR MODIFICATIONS.`
`34`	`34`	`*`
`35`	`35`	`* IDENTIFICATION`
`36`		`- * $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.63 2004/11/23 00:21:17 tgl Exp $`
	`36`	`+ * $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.64 2004/11/24 18:47:38 tgl Exp $`
`37`	`37`	`*`
`38`	`38`	`**********************************************************************/`
`39`	`39`
`@@ -238,13 +238,18 @@ plperl_safe_init(void)`
`238`	`238`	`;`
`239`	`239`
`240`	`240`	`SV *res;`
`241`		`- float safe_version;`
	`241`	`+ double safe_version;`
`242`	`242`
`243`	`243`	`res = eval_pv(safe_module, FALSE); /* TRUE = croak if failure */`
`244`	`244`
`245`	`245`	`safe_version = SvNV(res);`
`246`	`246`
`247`		`- eval_pv((safe_version < 2.09 ? safe_bad : safe_ok), FALSE);`
	`247`	`+ /*`
	`248`	`+ * We actually want to reject safe_version < 2.09, but it's risky to`
	`249`	`+ * assume that floating-point comparisons are exact, so use a slightly`
	`250`	`+ * smaller comparison value.`
	`251`	`+ */`
	`252`	`+ eval_pv((safe_version < 2.0899 ? safe_bad : safe_ok), FALSE);`
`248`	`253`
`249`	`254`	`plperl_safe_init_done = true;`
`250`	`255`	`}`