Hi internals,
I propose adding a preserve_key_types parameter to array_keys() to address issues caused by automatic conversion of string-numeric keys to integers.
Developer Experience Considerations
While PHP’s automatic conversion of numeric string keys to integers is documented behavior, real-world usage shows this feature continues to cause unexpected issues:
Cognitive Burden
As observed in a Reddit discussion:
“We understand the type coercion rules, but when converting ‘123’ to 123 still catches us off guard when debugging some problems.”
As we mentioned earlier, the array_keys method#### Production Risks
The implicit conversion creates hidden pitfalls:
php
复制
```
// Cache system failure example
$cache = ["123" => "data"]; // Redis expects string keys
$keys = array_keys($cache); // Returns [123] (int)
$redis->get($keys[0]); // Fails silently
```
Debugging Costs
Issues manifest only at runtime, requiring:
- Additional type validation code
- Defensive programming with
array_map('strval', ...) - Increased bug investigation time
Problem Examples#### Database Performance Issues
php
```
$orderIds = ["1001", "1002"]; // VARCHAR keys in database
$keys = array_keys($orderIds); // [1001, 1002] (unexpected int)
$db->query("SELECT * FROM orders WHERE id IN (".implode(',',$keys).")");
```
→ May cause full table scans when VARCHAR indexes are ignored.
Redis Cache Failures
php
```
$cacheData = ["user:1001" => "data", "user:1002" => "data"];
$keys = array_keys($cacheData); // ["user:1001", "user:1002"] (correct)
$numericData = ["1001" => "data", "1002" => "data"];
$numericKeys = array_keys($numericData); // [1001, 1002] (converted to int)
$redis->mget(array_merge($keys, $numericKeys)); // Partial failure
```
→ Mixed key types cause silent cache misses.
Proposal
Add a 4th parameter:
php
```
array_keys(
array $array,
mixed $search_value = null,
bool $strict = false,
bool $preserve_key_types = false
): array
```
When true, maintains original key types.
Questions for Discussion1. Design Considerations
- Should we provide a way to opt-out of this automatic conversion?
- Would a new parameter be preferable to a separate function (e.g.
array_keys_preserve())?
-
Use Case Validation
- Are the database and Redis examples sufficient to justify this change?
- Are there other common use cases we should consider?
-
Implementation Considerations
- Should we consider making this the default behavior in a future major version?
- Are there performance implications we should evaluate?
Looking forward to your feedback.
Best regards,
[xiaoma]