From 7f29418c63353bf0ccc5d3cc523c0f45cae7fd65 Mon Sep 17 00:00:00 2001
From: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Date: Thu, 10 Feb 2022 12:27:32 +0100
Subject: [PATCH] strconv: change atof64 to return an error, if the parsed
 value is not a valid number (#13424)

---
 vlib/builtin/string.v    |  4 ++--
 vlib/strconv/atof.c.v    | 12 +++++++++---
 vlib/strconv/atof.js.v   |  5 ++++-
 vlib/strconv/atof_test.v | 21 +++++++++++++++++++--
 vlib/v/eval/expr.v       |  2 +-
 5 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/vlib/builtin/string.v b/vlib/builtin/string.v
index 0504d828b..15083c33b 100644
--- a/vlib/builtin/string.v
+++ b/vlib/builtin/string.v
@@ -511,12 +511,12 @@ pub fn (s string) i16() i16 {
 
 // f32 returns the value of the string as f32 `'1.0'.f32() == f32(1)`.
 pub fn (s string) f32() f32 {
-	return f32(strconv.atof64(s))
+	return f32(strconv.atof64(s) or { 0 })
 }
 
 // f64 returns the value of the string as f64 `'1.0'.f64() == f64(1)`.
 pub fn (s string) f64() f64 {
-	return strconv.atof64(s)
+	return strconv.atof64(s) or { 0 }
 }
 
 // u8 returns the value of the string as u8 `'1'.u8() == u8(1)`.
diff --git a/vlib/strconv/atof.c.v b/vlib/strconv/atof.c.v
index 304c0d3c5..e60f4a1e2 100644
--- a/vlib/strconv/atof.c.v
+++ b/vlib/strconv/atof.c.v
@@ -104,6 +104,7 @@ pub const (
 	parser_mzero          = 2 // number is negative, module smaller
 	parser_pinf           = 3 // number is higher than +HUGE_VAL
 	parser_minf           = 4 // number is lower than -HUGE_VAL
+	parser_invalid_number = 5 // invalid number, used for '#@%^' for example
 	//
 	// char constants
 	// Note: Modify these if working with non-ASCII encoding
@@ -232,6 +233,9 @@ fn parser(s string) (int, PrepNumber) {
 			result = strconv.parser_pzero
 		}
 	}
+	if i == 0 && s.len > 0 {
+		return strconv.parser_invalid_number, pn
+	}
 	return result, pn
 }
 
@@ -403,9 +407,9 @@ fn converter(mut pn PrepNumber) u64 {
 // Public functions
 
 // atof64 return a f64 from a string doing a parsing operation
-pub fn atof64(s string) f64 {
+pub fn atof64(s string) ?f64 {
 	if s.len == 0 {
-		return 0
+		return error('expected a number found an empty string')
 	}
 	mut pn := PrepNumber{}
 	mut res_parsing := 0
@@ -428,7 +432,9 @@ pub fn atof64(s string) f64 {
 		strconv.parser_minf {
 			res.u = strconv.double_minus_infinity
 		}
-		else {}
+		else {
+			return error('not a number')
+		}
 	}
 	return unsafe { res.f }
 }
diff --git a/vlib/strconv/atof.js.v b/vlib/strconv/atof.js.v
index 45e2cd296..217851d23 100644
--- a/vlib/strconv/atof.js.v
+++ b/vlib/strconv/atof.js.v
@@ -1,7 +1,10 @@
 module strconv
 
 // atof64 return a f64 from a string doing a parsing operation
-pub fn atof64(s string) f64 {
+pub fn atof64(s string) ?f64 {
+	// TODO: handle parsing invalid numbers as close as possible to the pure V version
+	// that may be slower, but more portable, and will guarantee that higher level code
+	// works the same in the JS version, as well as in the C and Native versions.
 	res := 0.0
 	#res.val = Number(s.str)
 
diff --git a/vlib/strconv/atof_test.v b/vlib/strconv/atof_test.v
index ca286c8a8..069ea79ee 100644
--- a/vlib/strconv/atof_test.v
+++ b/vlib/strconv/atof_test.v
@@ -36,7 +36,8 @@ fn test_atof() {
 	// check conversion case 1 string <=> string
 	for c, x in src_num {
 		// slow atof
-		assert strconv.atof64(src_num_str[c]).strlong() == x.strlong()
+		val := strconv.atof64(src_num_str[c]) or { panic(err) }
+		assert val.strlong() == x.strlong()
 
 		// quick atof
 		mut s1 := (strconv.atof_quick(src_num_str[c]).str())
@@ -56,7 +57,8 @@ fn test_atof() {
 	// we don't test atof_quick beacuse we already know the rounding error
 	for c, x in src_num_str {
 		b := src_num[c].strlong()
-		a1 := strconv.atof64(x).strlong()
+		value := strconv.atof64(x) or { panic(err) }
+		a1 := value.strlong()
 		assert a1 == b
 	}
 
@@ -73,3 +75,18 @@ fn test_atof() {
 	assert *ptr == u64(0x8000000000000000)
 	println('DONE!')
 }
+
+fn test_atof_errors() {
+	if x := strconv.atof64('') {
+		eprintln('> x: $x')
+		assert false // strconv.atof64 should have failed
+	} else {
+		assert err.str() == 'expected a number found an empty string'
+	}
+	if x := strconv.atof64('####') {
+		eprintln('> x: $x')
+		assert false // strconv.atof64 should have failed
+	} else {
+		assert err.str() == 'not a number'
+	}
+}
diff --git a/vlib/v/eval/expr.v b/vlib/v/eval/expr.v
index 009e70969..07609f31e 100644
--- a/vlib/v/eval/expr.v
+++ b/vlib/v/eval/expr.v
@@ -191,7 +191,7 @@ pub fn (mut e Eval) expr(expr ast.Expr, expecting ast.Type) Object {
 			}) // TODO: numbers larger than 2^63 (for u64)
 		}
 		ast.FloatLiteral {
-			return f64(strconv.atof64(expr.val))
+			return f64(strconv.atof64(expr.val) or { e.error(err.str()) })
 		}
 		ast.BoolLiteral {
 			return expr.val
-- 
2.30.2