stage2 更多的工具库 stage1 修复问题

stage2/utils/fmt.spl

@@ -1,4 +1,5 @@
 // Expect retcode = 0
+
 // 数值/布尔格式化，写入 ByteBuffer。radix 取值 2..36；uppercase 只影响 10..35 的字母形式。
 // 不分配额外内存（除目标 ByteBuffer 自身扩容），失败不产生部分输出。
 
@@ -107,6 +108,7 @@ fn expect_text(buffer: *ByteBuffer, expected: []u8) {
 
 fn test_unsigned() {
     var b = ByteBuffer.new();
+    defer { ByteBuffer.drop(&b); }
 
     expect_ok(append_u64(&b, 0, 10, false));
     expect_text(&b, "0");
@@ -147,12 +149,11 @@ fn test_unsigned() {
     expect_ok(append_u64(&b, 18446744073709551615, 2, false));
     expect_text(&b, "1111111111111111111111111111111111111111111111111111111111111111");
     ByteBuffer.clear(&b);
-
-    ByteBuffer.drop(&b);
 }
 
 fn test_signed() {
     var b = ByteBuffer.new();
+    defer { ByteBuffer.drop(&b); }
 
     expect_ok(append_i64(&b, 0, 10, false));
     expect_text(&b, "0");
@@ -177,12 +178,11 @@ fn test_signed() {
     expect_ok(append_u64(&b, 48879, 16, true));
     expect_text(&b, "BEEF");
     ByteBuffer.clear(&b);
-
-    ByteBuffer.drop(&b);
 }
 
 fn test_usize_bool_and_errors() {
     var b = ByteBuffer.new();
+    defer { ByteBuffer.drop(&b); }
 
     expect_ok(append_usize(&b, 1000 as usize, 10, false));
     expect_text(&b, "1000");
@@ -201,12 +201,11 @@ fn test_usize_bool_and_errors() {
     expect_invalid(append_u64(&b, 1, 37, false));
     expect_invalid(append_i64(&b, -1, 0, false));
     @assert(ByteBuffer.size(b) == 0, "invalid radix writes nothing");
-
-    ByteBuffer.drop(&b);
 }
 
 fn test_composition_and_growth() {
     var b = ByteBuffer.new();
+    defer { ByteBuffer.drop(&b); }
 
     expect_ok(ByteBuffer.append(&b, "x="));
     expect_ok(append_i64(&b, -42, 10, false));
@@ -229,8 +228,6 @@ fn test_composition_and_growth() {
     var s = ByteBuffer.as_slice(b);
     @assert(s.ptr[0] == '0', "starts with 0");
     @assert(s.ptr[1] == ',', "0 then comma");
-
-    ByteBuffer.drop(&b);
 }
 
 fn main() {