From 59d408f72cfedcd3f9df59b3571544332c62ba0f Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Tue, 29 Jul 2025 07:37:53 +0300
Subject: [PATCH] v: limit -div-by-zero-is-zero influence to just the integer
 types (for f32 and f64, / produces a +inf or -inf value, and the program
 continues to run)

---
 vlib/v/gen/c/infix.v                                  | 4 ++--
 vlib/v/gen/c/testdata/div_by_zero_is_zero.c.must_have | 1 +
 vlib/v/gen/c/testdata/div_by_zero_is_zero.out         | 3 +++
 vlib/v/gen/c/testdata/div_by_zero_is_zero.vv          | 6 ++++++
 4 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/vlib/v/gen/c/infix.v b/vlib/v/gen/c/infix.v
index 22509fd0e1..c9ccdc9bd4 100644
--- a/vlib/v/gen/c/infix.v
+++ b/vlib/v/gen/c/infix.v
@@ -1204,8 +1204,6 @@ fn (mut g Gen) gen_plain_infix_expr(node ast.InfixExpr) {
 	needs_cast := node.left_type.is_number() && node.right_type.is_number()
 		&& node.op in [.plus, .minus, .mul, .div, .mod] && !(g.pref.translated
 		|| g.file.is_translated)
-	is_safe_div := node.op == .div && g.pref.div_by_zero_is_zero
-	is_safe_mod := node.op == .mod && g.pref.div_by_zero_is_zero
 	mut typ := node.promoted_type
 	mut typ_str := g.styp(typ)
 	if needs_cast {
@@ -1219,6 +1217,8 @@ fn (mut g Gen) gen_plain_infix_expr(node ast.InfixExpr) {
 		typ_str = g.styp(typ)
 		g.write('(${typ_str})(')
 	}
+	is_safe_div := node.op == .div && g.pref.div_by_zero_is_zero && typ.is_int()
+	is_safe_mod := node.op == .mod && g.pref.div_by_zero_is_zero && typ.is_int()
 	if node.left_type.is_ptr() && node.left.is_auto_deref_var() && !node.right_type.is_pointer() {
 		g.write('*')
 	} else if !g.inside_interface_deref && node.left is ast.Ident
diff --git a/vlib/v/gen/c/testdata/div_by_zero_is_zero.c.must_have b/vlib/v/gen/c/testdata/div_by_zero_is_zero.c.must_have
index c5ecb2fa19..18273e593d 100644
--- a/vlib/v/gen/c/testdata/div_by_zero_is_zero.c.must_have
+++ b/vlib/v/gen/c/testdata/div_by_zero_is_zero.c.must_have
@@ -1,2 +1,3 @@
 int c = (int)(VSAFE_DIV_int(a , z));
 int d = (int)(VSAFE_MOD_int(a , z));
+f32 fc = (f32)(fa / fz);
diff --git a/vlib/v/gen/c/testdata/div_by_zero_is_zero.out b/vlib/v/gen/c/testdata/div_by_zero_is_zero.out
index c338e4cdec..546262799d 100644
--- a/vlib/v/gen/c/testdata/div_by_zero_is_zero.out
+++ b/vlib/v/gen/c/testdata/div_by_zero_is_zero.out
@@ -2,3 +2,6 @@ a == 42
 z == 0
 c == a / z == 0
 d == a % z == 42
+fa == 42.0
+fz == 0.0
+fc == fa / fz == +inf
diff --git a/vlib/v/gen/c/testdata/div_by_zero_is_zero.vv b/vlib/v/gen/c/testdata/div_by_zero_is_zero.vv
index d1f280b7e8..493cd13356 100644
--- a/vlib/v/gen/c/testdata/div_by_zero_is_zero.vv
+++ b/vlib/v/gen/c/testdata/div_by_zero_is_zero.vv
@@ -7,3 +7,9 @@ println('a == ${a}')
 println('z == ${z}')
 println('c == a / z == ${c}')
 println('d == a % z == ${d}')
+fa := f32(42)
+fz := f32(0)
+fc := fa / fz
+println('fa == ${fa}')
+println('fz == ${fz}')
+println('fc == fa / fz == ${fc}')