fix: throw an exception if $cmd is not an indexed array

Author: SRWieZ

src/ChildProcess.php

@@ -58,7 +58,7 @@ public function start(
 ?array $env = null,
 bool $persistent = false
 ): static {
-$cmd = is_array($cmd) ? array_values($cmd) : [$cmd];
+$cmd = $this->ensureCmdIsAnIndexedArray($cmd);
 
 $process = $this->client->post('child-process/start', [
 'alias' => $alias,
@@ -73,8 +73,8 @@ public function start(
 
 public function php(string|array $cmd, string $alias, ?array $env = null, ?bool $persistent = false): self
 {
-$cmd = is_array($cmd) ? array_values($cmd) : [$cmd];
-
+$cmd = $this->ensureCmdIsAnIndexedArray($cmd);
+
 $process = $this->client->post('child-process/start-php', [
 'alias' => $alias,
 'cmd' => $cmd,
@@ -135,4 +135,15 @@ protected function fromRuntimeProcess($process): static
 
 return $this;
 }
+
+protected function ensureCmdIsAnIndexedArray(string|array $cmd): array
+{
+if (is_string($cmd)) {
+return [$cmd];
+}
+
+if (array_keys($cmd) !== range(0, count($cmd) - 1)) {
+throw new \InvalidArgumentException('Only indexed arrays are supported for the cmd: argument.');
+}
+}
 }