From a5f31d6eaa38b47ccd965a0009ebb9521835aa81 Mon Sep 17 00:00:00 2001
From: Yanhu007 <huangfuyang900204@gmail.com>
Date: Wed, 15 Apr 2026 06:09:49 +0800
Subject: [PATCH] fix: parse leading-zero strings as decimal instead of invalid
 octal
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

cast.ToInt("08") returned 0 because strconv.ParseInt with base 0
treats leading zeros as octal, and 8 is not a valid octal digit.

Now parseInt/parseUint try base 10 first, falling back to base 0
(auto-detect) for hex/octal/binary prefixed strings. This ensures:
- "08", "09" → 8, 9 (previously 0)
- "010" → 10 (previously 8, now decimal as users expect)
- "0xff" → 255 (still works via fallback)
- "0b1010" → 10 (still works via fallback)

Fixes #290
---
 number.go | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/number.go b/number.go
index a58dc4d..71b3abe 100644
--- a/number.go
+++ b/number.go
@@ -405,18 +405,32 @@ func parseNumber[T Number](s string) (T, error) {
 }
 
 func parseInt[T integer](s string) (T, error) {
-	v, err := strconv.ParseInt(trimDecimal(s), 0, 0)
+	s = trimDecimal(s)
+	// Try base-10 first so that leading-zero strings like "08" parse as
+	// decimal 8 instead of being rejected as invalid octal.
+	v, err := strconv.ParseInt(s, 10, 0)
 	if err != nil {
-		return 0, err
+		// Fall back to base-0 (auto-detect) to support "0x", "0o", "0b" prefixes.
+		v, err = strconv.ParseInt(s, 0, 0)
+		if err != nil {
+			return 0, err
+		}
 	}
 
 	return T(v), nil
 }
 
 func parseUint[T unsigned](s string) (T, error) {
-	v, err := strconv.ParseUint(strings.TrimLeft(trimDecimal(s), "+"), 0, 0)
+	s = strings.TrimLeft(trimDecimal(s), "+")
+	// Try base-10 first so that leading-zero strings like "08" parse as
+	// decimal 8 instead of being rejected as invalid octal.
+	v, err := strconv.ParseUint(s, 10, 0)
 	if err != nil {
-		return 0, err
+		// Fall back to base-0 (auto-detect) to support "0x", "0o", "0b" prefixes.
+		v, err = strconv.ParseUint(s, 0, 0)
+		if err != nil {
+			return 0, err
+		}
 	}
 
 	return T(v), nil