From 898b52edcb47bcb3e9d6106e74ca73e74ea01e70 Mon Sep 17 00:00:00 2001
From: sillylaird <sillyfanboy@gmail.com>
Date: Thu, 3 Sep 2026 00:33:59 +0000
Subject: import live www.sillylaird.ca webroot

---
 .../bug-detective/examples/debugging-workflow.py   | 241 +++++++++++++
 .../bug-detective/examples/debugging-workflow.sh   | 400 +++++++++++++++++++++
 .../examples/error-handling-patterns.py            | 305 ++++++++++++++++
 3 files changed, 946 insertions(+)
 create mode 100644 .agents/skills/bug-detective/examples/debugging-workflow.py
 create mode 100755 .agents/skills/bug-detective/examples/debugging-workflow.sh
 create mode 100644 .agents/skills/bug-detective/examples/error-handling-patterns.py

(limited to '.agents/skills/bug-detective/examples')

diff --git a/.agents/skills/bug-detective/examples/debugging-workflow.py b/.agents/skills/bug-detective/examples/debugging-workflow.py
new file mode 100644
index 0000000..0f76d27
--- /dev/null
+++ b/.agents/skills/bug-detective/examples/debugging-workflow.py
@@ -0,0 +1,241 @@
+"""
+调试流程示例
+
+这个示例展示了完整的调试流程，从发现问题到解决问题。
+"""
+
+import logging
+
+# 配置日志
+logging.basicConfig(level=logging.DEBUG, format='%(asctime)s - %(levelname)s - %(message)s')
+logger = logging.getLogger(__name__)
+
+
+# ============================================
+# 问题 1：IndexError
+# ============================================
+
+def get_item(items, index):
+    """
+    问题：直接访问索引可能导致 IndexError
+    
+    错误现象：
+    IndexError: list index out of range
+    """
+    # ❌ 有问题的代码
+    # return items[index]
+    
+    # ✅ 修复后的代码
+    if 0 <= index < len(items):
+        return items[index]
+    else:
+        logger.warning(f"索引 {index} 超出范围 [0, {len(items)})")
+        return None
+
+
+# ============================================
+# 问题 2：TypeError - 字符串拼接
+# ============================================
+
+def format_message(name, count):
+    """
+    问题：尝试拼接字符串和数字
+    
+    错误现象：
+    TypeError: can only concatenate str (not "int") to str
+    """
+    # ❌ 有问题的代码
+    # return name + ": " + count
+    
+    # ✅ 修复后的代码
+    return f"{name}: {count}"
+    # 或
+    # return name + ": " + str(count)
+
+
+# ============================================
+# 问题 3：KeyError
+# ============================================
+
+def get_user_info(users, user_id):
+    """
+    问题：直接访问字典中可能不存在的键
+    
+    错误现象：
+    KeyError: 'user_123'
+    """
+    # ❌ 有问题的代码
+    # return users[user_id]
+    
+    # ✅ 修复后的代码 - 方法1：使用 get()
+    return users.get(user_id, None)
+    
+    # ✅ 修复后的代码 - 方法2：检查键是否存在
+    # if user_id in users:
+    #     return users[user_id]
+    # return None
+
+
+# ============================================
+# 问题 4：AttributeError - None 对象
+# ============================================
+
+def process_data(data_provider):
+    """
+    问题：data_provider 可能返回 None
+    
+    错误现象：
+    AttributeError: 'NoneType' object has no attribute 'process'
+    """
+    data = data_provider.get_data()
+    
+    # ❌ 有问题的代码
+    # return data.process()
+    
+    # ✅ 修复后的代码
+    if data is not None:
+        return data.process()
+    else:
+        logger.error("数据为 None，无法处理")
+        return None
+
+
+# ============================================
+# 问题 5：修改正在迭代的列表
+# ============================================
+
+def remove_even_numbers(numbers):
+    """
+    问题：迭代时修改列表导致跳过元素
+    
+    错误现象：
+    某些偶数没有被移除
+    """
+    # ❌ 有问题的代码
+    # for num in numbers:
+    #     if num % 2 == 0:
+    #         numbers.remove(num)
+    # return numbers
+    
+    # ✅ 修复后的代码 - 方法1：列表推导式
+    return [num for num in numbers if num % 2 != 0]
+    
+    # ✅ 修复后的代码 - 方法2：使用副本
+    # for num in numbers[:]:
+    #     if num % 2 == 0:
+    #         numbers.remove(num)
+    # return numbers
+
+
+# ============================================
+# 调试技巧示例
+# ============================================
+
+def debug_with_logging(data):
+    """
+    使用日志追踪问题
+    """
+    logger.debug(f"输入数据: {data}")
+    
+    # 步骤 1
+    processed = step1(data)
+    logger.debug(f"步骤1结果: {processed}")
+    
+    # 步骤 2
+    result = step2(processed)
+    logger.debug(f"步骤2结果: {result}")
+    
+    return result
+
+
+def step1(data):
+    """模拟步骤1"""
+    return [x * 2 for x in data]
+
+
+def step2(data):
+    """模拟步骤2"""
+    return sum(data)
+
+
+# ============================================
+# 异常处理示例
+# ============================================
+
+def safe_divide(a, b):
+    """
+    正确的异常处理模式
+    """
+    try:
+        result = a / b
+        logger.info(f"{a} / {b} = {result}")
+        return result
+    except ZeroDivisionError:
+        logger.error(f"除数不能为零: {b}")
+        return None
+    except TypeError as e:
+        logger.error(f"类型错误: {e}")
+        return None
+
+
+# ============================================
+# 使用断言进行调试
+# ============================================
+
+def calculate_discount(price, discount_rate):
+    """
+    使用断言验证假设
+    """
+    # 断言：价格应该是正数
+    assert price > 0, f"价格应该是正数，实际: {price}"
+    
+    # 断言：折扣率应该在 0-1 之间
+    assert 0 <= discount_rate <= 1, f"折扣率应该在 0-1 之间，实际: {discount_rate}"
+    
+    discounted_price = price * (1 - discount_rate)
+    
+    # 断言：折扣后的价格应该小于原价
+    assert discounted_price <= price, "折扣价格应该小于原价"
+    
+    return discounted_price
+
+
+# ============================================
+# 测试代码
+# ============================================
+
+if __name__ == "__main__":
+    print("=" * 50)
+    print("调试示例")
+    print("=" * 50)
+    
+    # 测试 get_item
+    print("\n1. 测试 get_item:")
+    items = ['a', 'b', 'c']
+    print(f"get_item(items, 1) = {get_item(items, 1)}")
+    print(f"get_item(items, 10) = {get_item(items, 10)}")
+    
+    # 测试 format_message
+    print("\n2. 测试 format_message:")
+    print(f"format_message('Count', 42) = {format_message('Count', 42)}")
+    
+    # 测试 get_user_info
+    print("\n3. 测试 get_user_info:")
+    users = {'user_1': 'Alice', 'user_2': 'Bob'}
+    print(f"get_user_info(users, 'user_1') = {get_user_info(users, 'user_1')}")
+    print(f"get_user_info(users, 'user_999') = {get_user_info(users, 'user_999')}")
+    
+    # 测试 remove_even_numbers
+    print("\n4. 测试 remove_even_numbers:")
+    numbers = [1, 2, 3, 4, 5, 6]
+    print(f"原始: {numbers}")
+    print(f"结果: {remove_even_numbers(numbers)}")
+    
+    # 测试 safe_divide
+    print("\n5. 测试 safe_divide:")
+    print(f"safe_divide(10, 2) = {safe_divide(10, 2)}")
+    print(f"safe_divide(10, 0) = {safe_divide(10, 0)}")
+    
+    # 测试 calculate_discount
+    print("\n6. 测试 calculate_discount:")
+    print(f"calculate_discount(100, 0.2) = {calculate_discount(100, 0.2)}")
diff --git a/.agents/skills/bug-detective/examples/debugging-workflow.sh b/.agents/skills/bug-detective/examples/debugging-workflow.sh
new file mode 100755
index 0000000..1ff74a5
--- /dev/null
+++ b/.agents/skills/bug-detective/examples/debugging-workflow.sh
@@ -0,0 +1,400 @@
+#!/bin/bash
+#
+# Shell 脚本调试流程示例
+# 展示常见的 Bash 脚本错误和调试方法
+#
+
+# ============================================
+# 调试设置
+# ============================================
+
+# 取消注释以启用调试模式
+# set -x   # 打印每个命令
+# set -e   # 错误时退出
+# set -u   # 未定义变量报错
+# set -o pipefail  # 管道中任何命令失败则失败
+
+# 或组合使用
+# set -xeuo pipefail  # 严格模式
+
+
+# ============================================
+# 错误处理函数
+# ============================================
+
+# 错误退出函数
+die() {
+    local message="$1"
+    local exit_code="${2:-1}"
+    echo "Error: $message" >&2
+    exit "$exit_code"
+}
+
+# 记录函数
+log() {
+    local level="$1"
+    shift
+    echo "[$(date '+%Y-%m-%d %H:%M:%S')] [$level] $*" >&2
+}
+
+log_info() { log "INFO" "$@"; }
+log_warn() { log "WARN" "$@"; }
+log_error() { log "ERROR" "$@"; }
+
+
+# ============================================
+# 问题 1：未引用的变量
+# ============================================
+
+# 错误示例：变量未引用
+demo_unquoted_variable() {
+    echo "=== 问题 1：未引用的变量 ==="
+    
+    local name="John Doe"
+    
+    # 错误：变量未引用，空值会导致语法错误
+    # if [ $name = "John Doe" ]; then
+    #     echo "Match"
+    # fi
+    
+    # 正确：始终引用变量
+    if [ "$name" = "John Doe" ]; then
+        log_info "变量匹配: $name"
+    fi
+}
+
+
+# ============================================
+# 问题 2：命令失败继续执行
+# ============================================
+
+demo_command_failure() {
+    echo "=== 问题 2：命令失败继续执行 ==="
+    
+    # 错误：cd 失败后继续执行
+    # cd /nonexistent_directory
+    # rm -rf file.txt  # 会删除当前目录的文件！
+    
+    # 正确：检查命令是否成功
+    cd /tmp || die "无法切换到 /tmp 目录"
+    log_info "成功切换到目录: $(pwd)"
+    
+    cd - > /dev/null || true
+}
+
+
+# ============================================
+# 问题 3：循环中的变量作用域（管道问题）
+# ============================================
+
+demo_pipeline_scope() {
+    echo "=== 问题 3：管道中的变量作用域 ==="
+    
+    local count=0
+    
+    # 错误：管道创建子 shell，外部变量不改变
+    # echo -e "1\n2\n3" | while read line; do
+    #     count=$((count + 1))
+    # done
+    # echo "Count: $count"  # 输出 0
+    
+    # 正确：使用重定向
+    while read line; do
+        count=$((count + 1))
+    done < <(echo -e "1\n2\n3")
+    log_info "计数结果: $count"
+}
+
+
+# ============================================
+# 问题 4：数组操作
+# ============================================
+
+demo_array_operations() {
+    echo "=== 问题 4：数组操作 ==="
+    
+    local fruits=("apple" "banana" "cherry")
+    
+    # 错误的数组访问
+    # echo $fruits[1]  # 输出 apple[1]
+    
+    # 正确的数组访问
+    log_info "第一个元素: ${fruits[0]}"
+    log_info "第二个元素: ${fruits[1]}"
+    log_info "所有元素: ${fruits[@]}"
+    log_info "数组长度: ${#fruits[@]}"
+    
+    # 遍历数组
+    for fruit in "${fruits[@]}"; do
+        log_info "水果: $fruit"
+    done
+}
+
+
+# ============================================
+# 问题 5：字符串比较
+# ============================================
+
+demo_string_comparison() {
+    echo "=== 问题 5：字符串比较 ==="
+    
+    local name="John"
+    
+    # 错误：数字比较使用 =
+    # if [ $age = 18 ]; then
+    
+    # 正确：字符串比较
+    if [[ "$name" == "John" ]]; then
+        log_info "字符串匹配"
+    fi
+    
+    # 正确：数字比较
+    local age=18
+    if [ "$age" -eq 18 ]; then
+        log_info "数字匹配"
+    fi
+}
+
+
+# ============================================
+# 问题 6：算术运算
+# ============================================
+
+demo_arithmetic() {
+    echo "=== 问题 6：算术运算 ==="
+    
+    local a=10
+    local b=5
+    
+    # 错误：使用 let 或 $(())
+    # result = a + b  # 这是命令调用
+    
+    # 正确的算术运算
+    local result=$((a + b))
+    log_info "加法: $a + $b = $result"
+    
+    result=$((a - b))
+    log_info "减法: $a - $b = $result"
+    
+    result=$((a * b))
+    log_info "乘法: $a * $b = $result"
+    
+    result=$((a / b))
+    log_info "除法: $a / $b = $result"
+    
+    # 使用 let
+    let result=a+b
+    log_info "let 加法: $result"
+}
+
+
+# ============================================
+# 参数验证
+# ============================================
+
+validate_arguments() {
+    echo "=== 参数验证 ==="
+    
+    # 检查参数数量
+    if [ $# -lt 2 ]; then
+        die "用法: $0 <文件> <目录>" 2
+    fi
+    
+    local file="$1"
+    local dir="$2"
+    
+    # 检查文件存在
+    if [ ! -f "$file" ]; then
+        die "文件不存在: $file" 3
+    fi
+    
+    # 检查目录存在
+    if [ ! -d "$dir" ]; then
+        die "目录不存在: $dir" 4
+    fi
+    
+    log_info "参数验证通过"
+    log_info "文件: $file"
+    log_info "目录: $dir"
+}
+
+
+# ============================================
+# 使用 trap 进行清理
+# ============================================
+
+demo_trap() {
+    echo "=== 使用 trap 进行清理 ==="
+    
+    # 设置清理函数
+    cleanup() {
+        log_info "执行清理操作..."
+        # 这里可以执行清理操作
+    }
+    
+    # 捕获退出信号
+    trap cleanup EXIT
+    
+    # 捕获错误信号
+    trap 'log_error "发生错误，行号: $LINENO"' ERR
+    
+    # 捕获中断信号
+    trap 'log_warn "脚本被中断"; cleanup; exit 130' INT
+    
+    log_info "执行一些操作..."
+    # 模拟操作
+    sleep 1
+}
+
+
+# ============================================
+# 调试技巧示例
+# ============================================
+
+demo_debugging() {
+    echo "=== 调试技巧 ==="
+    
+    # 1. 使用 echo 调试
+    local value="test"
+    echo "[DEBUG] value = $value" >&2
+    
+    # 2. 使用 printf 格式化输出
+    printf "[DEBUG] Count: %d, Name: %s\n" 42 "John" >&2
+    
+    # 3. 检查变量是否设置
+    if [ -z "${unset_var+x}" ]; then
+        log_warn "变量 unset_var 未设置"
+    fi
+    
+    # 4. 显示调用栈
+    log_info "调用栈:"
+    local i=0
+    while caller $i; do
+        ((i++))
+    done 2>/dev/null || true
+}
+
+
+# ============================================
+# 文件操作错误处理
+# ============================================
+
+demo_file_operations() {
+    echo "=== 文件操作错误处理 ==="
+    
+    local tmpfile=$(mktemp) || die "无法创建临时文件"
+    
+    # 确保文件被删除
+    trap "rm -f '$tmpfile'" EXIT
+    
+    # 写入文件
+    echo "Test content" > "$tmpfile" || die "无法写入文件: $tmpfile"
+    
+    # 读取文件
+    local content
+    content=$(cat "$tmpfile") || die "无法读取文件: $tmpfile"
+    
+    log_info "文件内容: $content"
+    
+    # trap 会自动清理
+}
+
+
+# ============================================
+# 带重试的操作
+# ============================================
+
+demo_retry() {
+    echo "=== 带重试的操作 ==="
+    
+    local max_attempts=3
+    local attempt=1
+    
+    while [ $attempt -le $max_attempts ]; do
+        log_info "尝试 $attempt/$max_attempts..."
+        
+        # 模拟可能失败的操作
+        if [ $attempt -eq 2 ]; then
+            log_info "成功！"
+            return 0
+        fi
+        
+        log_warn "失败，重试..."
+        ((attempt++))
+        sleep 1
+    done
+    
+    log_error "所有尝试都失败了"
+    return 1
+}
+
+
+# ============================================
+# 检查依赖
+# ============================================
+
+check_dependencies() {
+    echo "=== 检查依赖 ==="
+    
+    local required_commands=("curl" "jq" "git")
+    
+    for cmd in "${required_commands[@]}"; do
+        if ! command -v "$cmd" &> /dev/null; then
+            log_error "缺少依赖: $cmd"
+            return 1
+        fi
+        log_info "✓ $cmd 可用"
+    done
+    
+    log_info "所有依赖都已满足"
+}
+
+
+# ============================================
+# 主函数
+# ============================================
+
+main() {
+    echo "============================================"
+    echo "Shell 脚本调试示例"
+    echo "============================================"
+    
+    # 运行各个示例
+    demo_unquoted_variable
+    echo ""
+    
+    demo_command_failure
+    echo ""
+    
+    demo_pipeline_scope
+    echo ""
+    
+    demo_array_operations
+    echo ""
+    
+    demo_string_comparison
+    echo ""
+    
+    demo_arithmetic
+    echo ""
+    
+    demo_trap
+    echo ""
+    
+    demo_debugging
+    echo ""
+    
+    demo_file_operations
+    echo ""
+    
+    demo_retry
+    echo ""
+    
+    check_dependencies
+    echo ""
+    
+    log_info "所有示例执行完成"
+}
+
+# 运行主函数
+main "$@"
diff --git a/.agents/skills/bug-detective/examples/error-handling-patterns.py b/.agents/skills/bug-detective/examples/error-handling-patterns.py
new file mode 100644
index 0000000..57d197e
--- /dev/null
+++ b/.agents/skills/bug-detective/examples/error-handling-patterns.py
@@ -0,0 +1,305 @@
+"""
+错误处理模式示例
+
+展示各种错误处理的最佳实践
+"""
+
+import logging
+from typing import Optional, List, Dict, Any
+from functools import wraps
+
+logger = logging.getLogger(__name__)
+
+
+# ============================================
+# 模式 1：具体异常捕获
+# ============================================
+
+def read_file(filepath: str) -> Optional[str]:
+    """
+    捕获具体异常而不是宽泛的 Exception
+    """
+    try:
+        with open(filepath, 'r') as f:
+            return f.read()
+    except FileNotFoundError:
+        logger.error(f"文件不存在: {filepath}")
+        return None
+    except PermissionError:
+        logger.error(f"没有权限读取文件: {filepath}")
+        return None
+    except UnicodeDecodeError:
+        logger.error(f"文件编码错误: {filepath}")
+        return None
+
+
+# ============================================
+# 模式 2：带重试的操作
+# ============================================
+
+def retry_operation(max_attempts: int = 3):
+    """
+    装饰器：自动重试失败的操作
+    """
+    def decorator(func):
+        @wraps(func)
+        def wrapper(*args, **kwargs):
+            for attempt in range(1, max_attempts + 1):
+                try:
+                    return func(*args, **kwargs)
+                except Exception as e:
+                    if attempt == max_attempts:
+                        logger.error(f"操作失败，已重试 {max_attempts} 次: {e}")
+                        raise
+                    logger.warning(f"操作失败，第 {attempt} 次重试...")
+            return None
+        return wrapper
+    return decorator
+
+
+@retry_operation(max_attempts=3)
+def unstable_api_call() -> Dict[str, Any]:
+    """
+    模拟不稳定的 API 调用
+    """
+    import random
+    if random.random() < 0.7:  # 70% 失败率
+        raise ConnectionError("API 连接失败")
+    return {"status": "success", "data": "result"}
+
+
+# ============================================
+# 模式 3：上下文管理器处理资源
+# ============================================
+
+class DatabaseConnection:
+    """
+    自定义上下文管理器，确保资源正确释放
+    """
+    def __init__(self, connection_string: str):
+        self.connection_string = connection_string
+        self.connection = None
+    
+    def __enter__(self):
+        logger.info(f"连接数据库: {self.connection_string}")
+        self.connection = f"Connection to {self.connection_string}"
+        return self.connection
+    
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        if exc_type is not None:
+            logger.error(f"发生异常: {exc_val}")
+        logger.info("关闭数据库连接")
+        # 清理资源
+        self.connection = None
+        return False  # 不抑制异常
+
+
+# ============================================
+# 模式 4：链式异常（保留原始异常）
+# ============================================
+
+def validate_and_process(data: Dict[str, Any]) -> Any:
+    """
+    使用 raise from 保留原始异常链
+    """
+    try:
+        # 验证数据
+        if 'value' not in data:
+            raise ValueError("数据中缺少 'value' 字段")
+        
+        value = data['value']
+        if not isinstance(value, (int, float)):
+            raise TypeError(f"value 应该是数字，实际类型: {type(value)}")
+        
+        # 处理数据
+        return value * 2
+        
+    except (ValueError, TypeError) as e:
+        # 保留原始异常并添加上下文
+        raise RuntimeError(f"数据处理失败: {data}") from e
+
+
+# ============================================
+# 模式 5：结果对象模式（不使用异常）
+# ============================================
+
+class Result:
+    """
+    结果对象模式：封装成功/失败状态
+    """
+    def __init__(self, success: bool, value: Any = None, error: str = None):
+        self.success = success
+        self.value = value
+        self.error = error
+    
+    @classmethod
+    def ok(cls, value: Any) -> 'Result':
+        return cls(success=True, value=value)
+    
+    @classmethod
+    def err(cls, error: str) -> 'Result':
+        return cls(success=False, error=error)
+    
+    def is_ok(self) -> bool:
+        return self.success
+    
+    def is_err(self) -> bool:
+        return not self.success
+    
+    def unwrap(self) -> Any:
+        if not self.success:
+            raise ValueError(f"尝试解包错误结果: {self.error}")
+        return self.value
+    
+    def unwrap_or(self, default: Any) -> Any:
+        return self.value if self.success else default
+
+
+def safe_divide_result(a: float, b: float) -> Result:
+    """
+    使用结果对象而不是异常
+    """
+    if b == 0:
+        return Result.err(f"除数不能为零: {b}")
+    
+    try:
+        return Result.ok(a / b)
+    except Exception as e:
+        return Result.err(f"计算失败: {e}")
+
+
+# ============================================
+# 模式 6：多项验证错误收集
+# ============================================
+
+class ValidationError(Exception):
+    """自定义验证错误"""
+    def __init__(self, errors: List[str]):
+        self.errors = errors
+        super().__init__("\n".join(errors))
+
+
+def validate_user(data: Dict[str, Any]) -> None:
+    """
+    收集所有验证错误而不是遇到第一个就停止
+    """
+    errors = []
+    
+    if 'name' not in data:
+        errors.append("缺少 'name' 字段")
+    elif not isinstance(data['name'], str):
+        errors.append("'name' 应该是字符串")
+    elif len(data['name']) < 2:
+        errors.append("'name' 长度应该至少为 2")
+    
+    if 'age' not in data:
+        errors.append("缺少 'age' 字段")
+    elif not isinstance(data['age'], int):
+        errors.append("'age' 应该是整数")
+    elif data['age'] < 0 or data['age'] > 150:
+        errors.append("'age' 应该在 0-150 之间")
+    
+    if 'email' in data and '@' not in data['email']:
+        errors.append("'email' 格式不正确")
+    
+    if errors:
+        raise ValidationError(errors)
+
+
+# ============================================
+# 模式 7：默认值和回退
+# ============================================
+
+def get_config(config: Dict[str, Any], key: str, default: Any = None) -> Any:
+    """
+    安全获取配置，支持多级键和默认值
+    """
+    if '.' in key:
+        # 支持嵌套键，如 "database.host"
+        keys = key.split('.')
+        value = config
+        for k in keys:
+            if isinstance(value, dict) and k in value:
+                value = value[k]
+            else:
+                return default
+        return value
+    
+    # 简单键
+    return config.get(key, default)
+
+
+# ============================================
+# 模式 8：优雅降级
+# ============================================
+
+def get_user_preferences(user_id: int) -> Dict[str, Any]:
+    """
+    尝试多种方法获取用户偏好，优雅降级
+    """
+    # 尝试 1：从缓存获取
+    try:
+        return _get_from_cache(user_id)
+    except Exception as e:
+        logger.warning(f"从缓存获取失败: {e}")
+    
+    # 尝试 2：从数据库获取
+    try:
+        return _get_from_database(user_id)
+    except Exception as e:
+        logger.warning(f"从数据库获取失败: {e}")
+    
+    # 尝试 3：使用默认配置
+    logger.info("使用默认配置")
+    return _get_default_preferences()
+
+
+def _get_from_cache(user_id: int) -> Dict[str, Any]:
+    # 模拟缓存失败
+    raise ConnectionError("缓存连接失败")
+
+
+def _get_from_database(user_id: int) -> Dict[str, Any]:
+    # 模拟数据库失败
+    raise ConnectionError("数据库连接失败")
+
+
+def _get_default_preferences() -> Dict[str, Any]:
+    return {
+        "theme": "light",
+        "language": "zh-CN",
+        "notifications": True
+    }
+
+
+# ============================================
+# 测试代码
+# ============================================
+
+if __name__ == "__main__":
+    logging.basicConfig(level=logging.INFO)
+    
+    print("=" * 50)
+    print("错误处理模式示例")
+    print("=" * 50)
+    
+    # 测试结果对象模式
+    print("\n1. 结果对象模式:")
+    result1 = safe_divide_result(10, 2)
+    print(f"10 / 2 = {result1.unwrap()}")
+    
+    result2 = safe_divide_result(10, 0)
+    print(f"10 / 0 = {result2.unwrap_or('N/A')} ({result2.error})")
+    
+    # 测试优雅降级
+    print("\n2. 优雅降级:")
+    prefs = get_user_preferences(123)
+    print(f"用户偏好: {prefs}")
+    
+    # 测试上下文管理器
+    print("\n3. 上下文管理器:")
+    try:
+        with DatabaseConnection("localhost:5432") as conn:
+            print(f"连接: {conn}")
+    except Exception as e:
+        print(f"操作失败: {e}")
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