fix: stop using is_string() for validation (#233)

Stop using is_string() for validation as it fails for strings that have
automatically been converted into integers when used as keys in
associative arrays.

Update isNullOrEmpty to check if the given value is a scalar (a string,
int, float, or bool) and then check if its string value is empty instead
of explicitly taking a string.

Remove a dictionary set fields test case that checks for an error when
given this array: [""]. PHP will implicitly treat it as this associative
array: [0 => ""], which is valid with our new validation. We need to
choose whether to support integer string keys or whether to be able to
reject this specific type of invalid input.

src/Utilities/_DataValidation.php

@@ -16,9 +16,11 @@ function validateTtl($ttlSeconds): void
 }
 
 if (!function_exists('isNullOrEmpty')) {
-    function isNullOrEmpty(?string $str = null): bool
+    function isNullOrEmpty($value): bool
     {
-        return (is_null($str) || $str === "");
+        // if the value is not null, check if the string value is empty. This covers strings that have been
+        // automatically converted into integers. Scalars cover int, float, string, and bool.
+        return is_null($value) || (is_scalar($value) && strval($value) === "");
     }
 }
 
@@ -68,7 +70,7 @@ function validateKeys(array $keys): void
         foreach ($keys as $key) {
             // Explicitly test type of key. If someone passes us a ["a", "b", "c"] style list upstream
             // instead of a ["key"=>"val"] dict, the "keys" will be integers and we want to reject the payload.
-            if (!is_string($key) || isNullOrEmpty($key)) {
+            if (isNullOrEmpty($key)) {
                 throw new InvalidArgumentError("Keys must all be non-empty strings");
             }
         }
@@ -196,12 +198,8 @@ function validateSortedSetRanks(?int $startRank, ?int $endRank): void
     function validateSortedSetElements(array $elements): void
     {
         foreach ($elements as $value => $score) {
-            if (!is_string($value)) {
-                throw new InvalidArgumentError("Sorted set value must be a string");
-            }
-
             if (!is_float($score)) {
-                throw new InvalidArgumentException("Sorted set score must be a float");
+                throw new InvalidArgumentError("Sorted set score must be a float");
             }
 
             validateValueName($value);
@@ -216,7 +214,7 @@ function validateSortedSetValues(array $values): void
             throw new InvalidArgumentError("sorted set values must be a non-empty array");
         }
         foreach ($values as $value) {
-            if (!is_string($value) || isNullOrEmpty($value)) {
+            if (isNullOrEmpty($value)) {
                 throw new InvalidArgumentError("sorted set values must all be non-empty strings");
             }
         }

tests/Cache/CacheClientTest.php

@@ -2119,10 +2119,6 @@ public function testDictionarySetFieldsWithNullItems_ThrowsException()
     public function testDictionarySetFieldsWithEmptyItems_IsError()
     {
         $dictionaryName = uniqid();
-        $items = [""];
-        $response = $this->client->dictionarySetFields($this->TEST_CACHE_NAME, $dictionaryName, $items, CollectionTtl::fromCacheTtl()->withNoRefreshTtlOnUpdates());
-        $this->assertNotNull($response->asError(), "Expected error but got: $response");
-        $this->assertEquals(MomentoErrorCode::INVALID_ARGUMENT_ERROR, $response->asError()->errorCode());
 
         $items = [];
         $response = $this->client->dictionarySetFields($this->TEST_CACHE_NAME, $dictionaryName, $items, CollectionTtl::fromCacheTtl()->withNoRefreshTtlOnUpdates());
@@ -2240,7 +2236,7 @@ public function testDictionaryGetFieldsWithEmptyFields_IsError()
     public function testDictionaryGetFields_HappyPath()
     {
         $dictionaryName = uniqid();
-        $field1 = uniqid();
+        $field1 = "1234"; // explicit integer-like string to make sure php casting doesn't break validation
         $field2 = uniqid();
         $field3 = uniqid();
         $value1 = uniqid();
@@ -2267,7 +2263,7 @@ public function testDictionaryGetFields_HappyPath()
     public function testDictionaryGetBatchFieldsValuesArray_HappyPath()
     {
         $dictionaryName = uniqid();
-        $field1 = uniqid();
+        $field1 = "1234"; // explicit integer-like string to make sure php casting doesn't break validation
         $field2 = uniqid();
         $field3 = uniqid();
         $value1 = uniqid();